The Commodore 64, also called the C64, is an 8-bit home computer introduced in January 1982 by Commodore International. It was first shown at the Consumer Electronics Show in Las Vegas from January 7 to 10, 1982. The Commodore 64 is listed in the Guinness World Records as the best-selling desktop computer model of all time, with estimates suggesting between 12.5 and 17 million units were sold. Production began in early 1982, and it was marketed in August 1982 for $595 (equivalent to $1,990 in 2025). The C64 followed the VIC-20 and Commodore PET computers and was named for its 64 kibibytes (65,536 bytes) of RAM. It used special hardware, including a chip for creating sound and images, to produce better visuals and audio than other systems without similar technology.
The C64 was the most popular computer in the low-end market during much of the 1980s, except in the UK, France, and Japan. In the United States, it held between 30% and 40% of the market share from 1983 to 1986, selling about 2 million units each year. It sold more units than IBM PC compatibles, Apple II computers, and Atari 8-bit computers. Sam Tramiel, who later became president of Atari, said in a 1989 interview, "When I was at Commodore, we were building 400,000 C64s a month for a couple of years." In the UK, the C64 competed with the BBC Micro, ZX Spectrum, and Amstrad CPC 464, but it remained the second-most-popular computer after the ZX Spectrum. The C64 did not succeed in Japan, where Japanese computers like the NEC PC-8801, Sharp X1, Fujitsu FM-7, and MSX dominated. In France, the ZX Spectrum, Thomson MO5, TO7, and Amstrad CPC 464 were more popular.
The C64’s success was partly due to its availability in regular retail stores, not just specialty electronics shops. Commodore made many parts in-house to keep costs low, including custom chips from MOS Technology. In the United States, the C64 is often compared to the Ford Model T for its role in making computers affordable for middle-class families through mass production. Over 10,000 software programs were created for the C64, including tools for work, games, and productivity applications. Today, C64 emulators allow modern computers and video game consoles to run these programs. The C64 helped popularize the computer demoscene, a community focused on creating visual and audio demonstrations. It is still used by some hobbyists. In 2011, 17 years after it was discontinued, studies showed that 87% of people still recognized the C64 brand.
History
In January 1981, MOS Technology, Inc., a company that designs computer parts for Commodore, started a project to create new chips for a video game console. These chips, called the MOS Technology VIC-II (for graphics) and MOS Technology SID (for sound), were finished in November 1981. Commodore then began a project to build a new console called the Ultimax or MAX Machine, designed by Yash Terakura from Commodore Japan. However, the project was stopped after only a few units were made for Japan. At the same time, Robert "Bob" Russell (a programmer for the VIC-20) and Robert "Bob" Yannes (a designer of the SID chip) were unhappy with Commodore’s current products, which focused on business users. With help from Al Charpentier (a designer of the VIC-II) and Charles Winterble (a manager at MOS Technology), they suggested to Commodore’s CEO, Jack Tramiel, that the company should make a low-cost version of the VIC-20. Tramiel wanted the new computer to have 64 KB of memory. Even though memory chips cost more than $100 at the time, he believed prices would drop before full production. Because Commodore had its own factory to make test chips, the team could design the computer quickly. The chips were ready by November, and Tramiel set a deadline for the first weekend of January 1982, so the product could be shown at the Consumer Electronics Show (CES).
The new computer was first called the VIC-40, as a follow-up to the popular VIC-20. The team that built it included Yash Terakura, Shiraz Shivji, Bob Russell, Bob Yannes, and David A. Ziembicki. They finished the design, prototypes, and sample software in time for the show, working hard during Thanksgiving and Christmas. The machine used the same case, motherboard size, and Commodore BASIC 2.0 in ROM as the VIC-20. BASIC also acted as the main user interface and started automatically with the message "READY." When the product was shown, it was renamed the C64. The C64 made a strong first impression at the January 1982 CES, as described by engineer David A. Ziembicki: "People from Atari were shocked, saying, 'How can you make this for $595?'" The answer was vertical integration, meaning Commodore owned its own chip-making factory, which kept production costs low. Each C64 cost about $135 to make.
In July 1983, BYTE magazine noted that the C64 sold for $595 and could be a top competitor in the under-$1,000 computer market. It praised the SID chip as a high-quality music synthesizer but criticized Commodore BASIC 2.0, the slow floppy disk drive, and quality control. The magazine said BASIC 2.0 had limited features, likely because Commodore expected users to rely on pre-made software rather than programming directly. This was one of the few times a magazine warned about BASIC 2.0. In December 1984, Creative Computing called the C64 the best home computer under $500, despite issues like a slow disk drive and limited ports. It noted that no other system offered the same features at that price. The Tandy Color Computer was the second-place finisher, and the Apple II won the category for computers over $500.
Commodore had a history of announcing products that never reached the market, so it aimed to release the C64 quickly. Production started in spring 1982, and large shipments began in August. The C64 faced competition from many home computers, but its lower price and flexible design helped it sell more than many rivals.
In the United States, the main competitors were the Atari 8-bit computers, the Apple II, and the TI-99/4A. The Atari 400 and 800 were expensive to make because they met strict FCC rules. The C64 and Apple II had different designs: the Apple II used expansion slots for peripherals, while the C64 had fewer ports. However, the C64 had ports built into its motherboard, which made it easier to use. Commodore shared technical details for its computers, unlike the TI-99/4A, which focused on less technical users. Early C64 sales were slow due to limited software, problems with the PLA chip, and shortages of disk drives. By 1983, more software became available, and sales grew quickly.
Commodore sold the C64 through stores like department stores, toy shops, and colleges. It had an RF modulator, allowing it to connect to any TV, competing with video game consoles like the Atari 2600. Like the Apple IIe, the C64 could also connect to a monitor for better video quality. The C64’s NTSC output included separate signals for color and brightness, similar to S-Video, which improved picture quality.
The C64’s low price played a major role in the video game crash of 1983. In January 1983, Commodore offered a $100 discount to customers who traded in other consoles or computers. Some stores sold the Timex Sinclair 1000 for as little as $10 with a C64 purchase. This deal allowed buyers to send the TS1000 to Commodore and keep the rebate money. Timex left the computer market within a year.
C64 family
In 1982, Commodore released the MAX Machine in Japan. It was called the Ultimax in the United States and the VC-10 in Germany. The MAX was designed as a game console with limited computing power. It used a simpler version of the hardware later used in the C64. The MAX was stopped from being sold months after its release because it did not sell well in Japan.
In 1983, Commodore tried to compete with the Apple II in the US education market by releasing the Educator 64. This device was a C64 with a green monochrome monitor in a PET case. Schools liked the PET’s all-in-one metal design better than the C64’s separate parts, which were easier to break or steal. Schools did not prefer the Educator 64 over the Apple IIe because the Apple IIe had more software and hardware choices. The Educator 64 was made in small numbers.
Also in 1983, Commodore released the SX-64, a portable version of the C64. The SX-64 was the first commercial full-color portable computer. Earlier portable computers only had black-and-white displays, but the SX-64 had a 5-inch color screen and one built-in 1541 floppy disk drive. Commodore advertised that the SX-64 would have two floppy drives, but only one was included. The second drive became a storage slot. Unlike most C64 models, the SX-64 did not have a datasette connector, so users could not use external cassette tapes.
Two Commodore designers, Fred Bowen and Bil Herd, wanted to fix problems with the Plus/4. They planned the next models after the C64—the Commodore 128 and 128D (1985)—to improve on the C64 and avoid the Plus/4’s flaws. These models had better features, such as a BASIC version with graphics and sound commands, an 80-column display, and full CP/M compatibility. Without approval from management, Bowen and Herd secretly designed the C128 to be plug-compatible with the C64. They kept the plan secret until the project was too far along to change. When Commodore’s marketing team learned about the C128’s compatibility with the C64, they announced it would be 100% compatible, raising expectations for C64 support. To meet this goal, the C128 was redesigned to include a separate "64 mode" with a complete C64 environment.
The C64’s designers planned a new, wedge-shaped case within a year of its release, but this change never happened. In 1986, Commodore released the 64C, which was the same as the original C64 but had a newer design. The 64C was nicknamed the "Breadbin 64" after the 64C’s release. Its design was updated to look like the Commodore 128. The 64C used newer versions of the SID, VIC-II, and I/O chips. Some models had graphic symbols printed on the top of the keys instead of the front. The sound chip (SID) was changed to use the MOS 8580 chip, reducing its voltage from 12V to 9V. This change affected how some music and sound effects sounded. The 64 KiB of RAM was moved from eight chips to two. BASIC and the KERNAL were combined into one 16 KiB ROM chip. The PLA chip and some TTL chips were integrated into a single DIL 64-pin chip. The "252535-01" PLA chip also included color RAM. The smaller size made it impossible to add some internal expansions, like a floppy-speeder. In the US, the 64C was often sold with the GEOS graphical user interface and software for Quantum Link. The 1541 drive was also redesigned as the 1541C. Later, a smaller 1541-II model and the 800 KB 3.5-inch microfloppy 1581 were released.
In 1990, the C64 was repackaged as a game console called the C64 Games System (C64GS). Most external connections were removed. A simple change to the 64C’s motherboard allowed cartridges to be inserted from above. A modified ROM replaced the BASIC interpreter with a boot screen that told users to insert a cartridge. Designed to compete with the Nintendo Entertainment System and Sega’s Master System, the C64GS sold poorly compared to its rivals. It was a commercial failure and was never sold outside Europe. The C64GS lacked a keyboard, so software requiring a keyboard could not be used.
In 1990, Commodore began planning an advanced successor to the C64 called the Commodore 65 (also known as the "C64DX"). The project was canceled in 1991 by Commodore’s chairman, Irving Gould. The C65 had impressive features for an 8-bit computer, including the ability to display 256 colors on screen, which was more than the 64 colors available on some Amigas. However, no specific reason was given for canceling the C65. It would have competed with Commodore’s lower-end Amigas and the Commodore CDTV.
Software
In 1982, the Commodore 64 (C64) had graphics and sound features that were compared only with the Atari 8-bit computers. These features were much better than those of the Apple II, which was a popular computer at the time. The C64 is often credited with starting the demoscene, a type of computer art and music culture. Today, the C64 is still used in the demoscene, especially for making music. Its SID sound chip, which was used in the C64, is also used in special sound cards for personal computers and in a synthesizer called the Elektron SidStation. Even though other computers later became better, the C64 remained a strong competitor to video game consoles like the Nintendo Entertainment System (NES) and the Master System. This was partly because the C64 already had a large collection of software available.
In the United Kingdom, many C64 users had lower incomes and the ZX Spectrum was very popular. Because of this, most British C64 software was stored on cassette tapes. In the United States, few cassette-based C64 programs were released after 1983. In North America, software was mostly distributed using diskettes. The C64 had a cartridge slot, but it was mainly used in the first two years it was sold in the United States. Once disk drives became more affordable and reliable, the cartridge slot became less useful. A few games in the PAL region (used in Europe and other parts of the world) used bank-switched cartridges to work around the C64’s 16 KiB memory limit.
Like many home computers from the early 1980s, the C64 came with a BASIC interpreter stored in its ROM. This interpreter allowed users to write and run simple programs. The KERNAL, input/output (I/O), and operations for tape and disk drives were accessed through special BASIC commands. The disk drive had its own microprocessor and firmware (software stored in the drive’s ROM), similar to earlier systems like the CBM/PET and Atari 400 and 800. This design meant that no memory was used for a disk operating system, unlike earlier systems such as the Apple II and TRS-80.
The C64 used Commodore BASIC 2.0 instead of the more advanced BASIC 4.0 from the PET series. This was because the company believed most C64 users would not need the disk-related features of BASIC 4.0. Using BASIC 2.0 made it easier for users who had previously owned the VIC-20 computer to switch to the C64. The version of Microsoft BASIC included in the C64 did not have specific commands for sound or graphics. Instead, users had to use the "PEEK and POKE" commands to directly control the graphics and sound chip registers. To add more commands, including graphics and sound, Commodore created two cartridge-based extensions to BASIC 2.0: Simons’ BASIC and Super Expander 64. Other programming languages available for the C64 included Pascal, C, Logo, Forth, and FORTRAN. Compilers for BASIC 2.0, such as Petspeed 2, Blitz, and Turbo Lightning, were also developed. Most commercial C64 software was written in assembly language, either created on a larger computer or directly on the C64 using a machine code monitor or assembler. This method made programs faster and used less memory. Some games, especially adventure games, used high-level scripting languages and sometimes combined BASIC with machine language.
Many third-party operating systems were created for the C64. In addition to the original GEOS, two other GEOS-compatible systems, Wheels and GEOS megapatch, were developed. These systems required hardware upgrades to the original C64. Other operating systems available for the C64 included WiNGS OS, the Unix-like LUnix (which used a command-line interface), and the embedded systems OS Contiki, which had a full graphical user interface (GUI). Other less well-known operating systems included ACE, Asterix, DOS/65, and GeckOS. C64 OS, which is not a full operating system, is still being developed today. It includes a full GUI in character mode and other modern features. A version of CP/M was also released for the C64, but it required adding an external Z80 processor to the expansion bus. The Z80 processor was slowed down to work with the C64’s memory system, which made it perform poorly compared to other CP/M systems. C64 CP/M and C128 CP/M had limited software support because most commercial CP/M software could not run on these systems due to differences in disk formats. The low use of CP/M on Commodore computers meant that software companies did not create versions for the C64’s disk format. The C64 CP/M cartridge was only compatible with early versions of the C64’s motherboard.
During the 1980s, the Commodore 64 was used to run bulletin board systems (BBS) with software such as Punter BBS, Bizarre 64, Blue Board, C-Net, Color 64, CMBBS, C-Base, DMBBS, Image BBS, EBBS, and The Deadlock Deluxe BBS Construction Kit. These systems were sometimes modified by system operators (sysops) and used to share cracked software. As late as December 2013, 25 such BBS systems were still in use and could be accessed through the Telnet protocol. Major online services during this time included Compunet (UK), CompuServe (US, later bought by America Online), The Source (US), and Minitel (France). These services usually required custom software, which was often bundled with a modem and included free online time billed by the minute. Quantum Link (Q-Link) was an online service for Commodore 64 and 128 computers that operated from 1985 to 1994. It was run by Quantum Computer Services, which later changed its name to America Online. Q-Link was based on the PlayNET system, which was licensed from Control Video Corporation (CVC, later renamed Quantum Computer Services).
The first graphical character-based interactive environment was called Club Caribe. It was first released as Habitat in 1988 and was introduced by LucasArts for Q-Link users on Commodore 64 computers. Users could interact with each other, chat, and exchange items. While the game’s open world was very basic, its use of online avatars and the combination of chat and graphics was a major innovation. Online graphics in the late 1980s were limited by
Hardware
The Commodore 64 uses a special computer chip called the MOS Technology 6510. This chip is very similar to another chip called the 6502 but has some small differences, like different wiring and how it sends signals. The 6510 has six extra lines on its 40-pin package. These lines help the computer switch between different parts of its memory and control a tape recorder. The C64 has 64 kilobytes of dynamic RAM, 1 kilobyte of static RAM for showing text, and 38 kilobytes of memory for the built-in BASIC programming language. It also has 20 kilobytes of ROM, which includes the BASIC interpreter, the KERNAL, and character data. Because the computer’s processor can only access 64 kilobytes of memory at a time, the ROM is mapped into the memory, leaving only 38,911 bytes of RAM available when the computer starts. Most early C64 models used 4164 DRAM chips, which required eight chips to make a full byte of memory. Later models used 41464 DRAM chips, which needed fewer chips to store the same amount of memory. If any of the DRAM chips are missing, the computer will not work properly.
When the C64 starts, it checks its memory for errors. If a problem is found, the available memory for BASIC will be less than normal. If the faulty chip is in a specific area, the computer might show an error message instead of the usual BASIC startup screen.
The C64 uses a complex system to manage its memory. When it starts, the BASIC ROM is mapped to a specific memory range, and the KERNAL ROM (which controls the computer’s hardware) is mapped to another range. The memory under these ROMs can be written to but not read from without removing the ROMs. A special register at memory location $01 controls whether the ROMs and I/O area are active. If the KERNAL ROM is removed, BASIC will also be removed, as BASIC relies on the KERNAL for many functions.
The character ROM, which stores text and graphics data, is usually hidden from the computer’s processor. It can be made visible by moving it to a specific memory range, but this requires removing the I/O registers first. When the I/O registers are removed, that memory range becomes available for other uses.
Cartridges for the C64 are placed in specific memory ranges. Some cartridges automatically start programs by placing a special code in memory. A few early cartridges used a feature called Ultimax mode, which changed how memory was used. These cartridges could interfere with the KERNAL ROM and required programmers to handle system interrupts. The cartridge port has 16 address lines, allowing access to the entire memory space if needed. Software loaded from disks or tapes usually starts at the beginning of BASIC memory and uses a small BASIC command to jump to the program. Some software changed the way the computer starts programs so they would run automatically without user input.
About 300 cartridges were made for the C64, mostly in the first 2.5 years it was sold. Later, software needed more memory than the 16 KB limit of cartridges, so companies used bank-switched cartridges to store larger programs. One popular expansion was the Power Cartridge, which added tools for programming and faster data access. Larger companies also used bank-switched cartridges to overcome the memory limit.
Commodore did not include a reset button on its computers until later models, but some third-party cartridges had one. A soft reset can be done by running a specific command in memory. Some programs used this as a way to exit.
The KERNAL ROM was updated three times to fix problems. The first version was used only in early models and could not detect if the video chip was NTSC or PAL. The second version was used from 1982 to 1985. The third version was used in later models and the C64C. The 6510 processor runs at 1.023 MHz for NTSC models and 0.985 MHz for PAL models, slower than some other computers. Performance can be slightly improved by disabling the video chip’s output. This is used by programs that load data quickly from tapes or disks.
The restore key on the C64 is connected directly to the computer’s NMI line. Pressing it triggers an interrupt. If the run/stop key is not pressed, the computer ignores the interrupt. The run/stop-restore combination usually resets the computer’s settings without clearing memory. Some programs disable this feature to prevent accidental resets.
The C64 uses the same joystick port as the VIC-20 and adds another. Atari-style joysticks can be used, but some software may cause conflicts. Sega gamepads are not recommended, as they might damage the computer’s hardware. The SID chip has an analog input for controlling paddles, which some early games used. In 1986, Commodore released two mice for the C64 and C128. One was a digital mouse, and the other used analog sensors.
The VIC-II graphics chip has a new color palette, can display up to 112 sprites on a screen, and supports scrolling and two types of bitmap graphics.
The standard text mode has 40 columns, like the Commodore PET. The text uses a special encoding called PETSCII, which is different from standard ASCII. The KERNAL sets the screen to a dark-blue background with a light-blue border when the computer starts. Unlike the PET and VIC-20, the C64 uses double-width text. Some early models had blurry images due to poor video quality. Most screenshots show borders around the screen, a feature of the VIC-II chip. The computer can reset hardware registers using interrupts to adjust settings.
Clones and other reuse of the Commodore 64 name
C64 clones are computers that copy the functions of the Commodore 64. In mid-2004, after being off the market for more than 10 years, PC company Tulip Computers (which owned the Commodore brand since 1997) introduced the C64 Direct-to-TV (C64DTV). This was a game console with a joystick, based on the C64, and included 30 games stored in its memory. Designed by Jeri Ellsworth, a self-taught computer designer who previously created the C-One C64 version, the C64DTV was similar to other small consoles inspired by the Atari 2600 and Intellivision. The C64DTV was sold on QVC in the United States during the 2004 holiday season.
In 2015, Individual Computers produced a motherboard compatible with the Commodore 64. Called the C64 Reloaded, it was a redesigned version of the original Commodore 64 motherboard (revision 250466) with new features. The motherboard was meant to fit into an existing empty C64 or C64C case. Made in limited numbers, some models had special sockets for custom C64 chips. The board included switches to use different versions of the VIC-II and SID chips and allowed switching between PAL and NTSC video systems. It also had features like selecting KERNAL and character ROMs using the restore key, a reset button on the power switch, and an S-Video port to replace the original TV modulator. The motherboard used a DC-to-DC converter that ran on 12 V DC from a power adapter, instead of the original Commodore 64 power supply, which was known to fail often.
In 1998, the Commodore 64 brand was used again for the Web.it Internet Computer. This was a low-powered, Internet-focused computer that ran MS-DOS and Windows 3.1. It used an AMD Élan SC400 chip, had 16 MB of RAM, a 3.5-inch floppy disk drive, a 56k modem, and a PC Card. Despite its name, the Web.it looked different from the original Commodore 64 and could only work with it through included software that mimicked its functions. In 2011, Commodore USA, a company licensed to use the Commodore trademark, began selling PC clones called C64x. These had cases similar to the original C64 but used x86 architecture and were not compatible with the original Commodore 64.
Several Commodore 64 games were made available on the Nintendo Wii’s Virtual Console service in Europe and North America. These games were removed from the service in August 2013.
A British company called Retro Games released two unofficial consoles that mimic the Commodore 64 using Linux. These were THEC64 Mini (2018) and the full-size THEC64 (2019). Retro Games did not license the use of Commodore trademarks, so the name THEC64 (without a space) was used instead of "C64." This also meant the original Commodore key on the keyboard was replaced with a THEC64 key.
THEC64 Mini is a small, decorative version of the Commodore 64 with two USB ports, one HDMI port, and a mini USB connection for power. Its keyboard does not work, and the system is controlled using a included THEC64 joystick or a separate USB keyboard. The console uses the VICE emulator, which can also load additional software ROMs.
The full-size THEC64 is the same size as the original Commodore 64 and has a working keyboard. It includes features like VIC-20 emulation, two extra USB ports, and an improved joystick.
- THEC64 Mini (top) next to an original C64
- Full-size THEC64 in its original box
In December 2025, Commodore International released the Commodore 64 Ultimate. This is an FPGA-based remake of the Commodore 64, with features like HDMI output and the ability to load software via USB, Wi-Fi, or Ethernet.
Emulators
Commodore 64 emulators are programs that allow users to play games and run software from the original Commodore 64 computer. Examples include VICE, Hoxs64, and CCS64, which are open source, meaning their code is freely available for others to use and modify. An iPhone app was also created that includes versions of Commodore 64 games and programs adapted for mobile devices.
The Commodore PET, introduced in July 2015, is a smartphone that uses the Android operating system. It includes built-in emulators for the Commodore 64 and Amiga computers, allowing users to experience software from these older systems on modern devices.