The Commodore 64, also called the C64, is an 8-bit home computer that was first 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. Estimates suggest that 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 came after the VIC-20 and Commodore PET computers. Its name comes from the 64 kibibytes (65,536 bytes) of memory it had. The C64 used special hardware, such as a chip for creating colors and sounds, which allowed it to produce better visuals and audio than other systems without similar technology.
The C64 was very popular in the low-end computer market during the late 1980s, except in the UK, France, and Japan. In Japan, it was only popular for about six months. From 1983 to 1986, the C64 had between 30% and 40% of the US computer market, selling about two 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 and was the son of Commodore’s founder, 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. It was the second-most-popular computer in the UK after the ZX Spectrum. In Japan and France, the C64 did not gain much popularity because those markets were dominated by other computers, such as the NEC PC-8801, Sharp X1, Fujitsu FM-7, MSX, ZX Spectrum, Thomson MO5, TO7, and Amstrad CPC 464.
Part of the C64’s success was that it was sold in regular retail stores, not just in specialty electronics or computer stores. Commodore made many parts in-house to keep costs low, including special chips from MOS Technology. In the United States, the C64 is often compared to the Ford Model T because both helped bring new technology to middle-class homes through affordable mass production. About 10,000 software programs were created for the C64, including tools for work, games, and other applications. Today, C64 emulators allow people to use these programs on modern computers or video game consoles. The C64 is also credited with helping start the computer demoscene, a group of hobbyists who create visual and audio displays. In 2011, 17 years after it was no longer sold, surveys showed that 87% of people still recognized the Commodore 64 brand.
History
In January 1981, MOS Technology, Inc., a company owned by Commodore that designed computer chips, began working on new chips for a video game console. These chips, called the MOS Technology VIC-II (for graphics) and MOS Technology SID (for sound), were completed in November 1981. Commodore then started a project to build a new console called the Ultimax or MAX Machine, led 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 (the engineer of the SID chip) were unhappy with Commodore’s current products, which were based on the Commodore PET and aimed at business users. With help from Al Charpentier (engineer of the VIC-II) and Charles Winterble (manager of MOS Technology), they suggested to Commodore’s CEO, Jack Tramiel, that they build a low-cost follow-up to the VIC-20. Tramiel wanted the new computer to have 64 KB of RAM, even though RAM chips were expensive at the time. He believed prices would drop before full production began. Because Commodore had its own chip-making factory, which was not fully used, the team could design the computer quickly and at lower cost. The chips were finished by November 1981, and Tramiel set a deadline for the first weekend of January 1982 to prepare for the Consumer Electronics Show (CES).
The new computer was first called the VIC-40, as a successor to the popular VIC-20. The team included Yash Terakura, Shiraz Shivji, Bob Russell, Bob Yannes, and David A. Ziembicki. They worked hard during Thanksgiving and Christmas to finish the design, prototypes, and sample software in time for the show. The C64 used the same case, motherboard size, and Commodore BASIC 2.0 as the VIC-20. BASIC was the user interface and appeared immediately when the computer started. At the show, the product was renamed the C64. David A. Ziembicki remembered that people from Atari were surprised, asking, “How can you do that 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 reported that the C64 sold for $595 and could be a strong competitor in the under-$1,000 computer market. The magazine praised the SID chip as a high-quality sound synthesizer but criticized Commodore BASIC 2.0, the slow floppy disk drive, and quality control. It noted that BASIC 2.0 had limited features, such as the need to use POKE commands for graphics or sound. In December 1984, Creative Computing said the C64 was the best home computer under $500, despite its slow disk drive and limited ports. The Tandy Color Computer was the runner-up, and the Apple II won in the over-$500 category.
Commodore had a history of announcing products that never reached the market, so it aimed to launch the C64 quickly. Production started in spring 1982, and large shipments began in August. The C64 faced competition from computers like the Atari 8-bit, Apple II, and TI-99/4A. The Atari 400 and 800 were expensive to make due to FCC requirements. The Apple II had open architecture with expansion slots, while the C64 had a closed design with only one cartridge port. However, the C64 had built-in ports for peripherals, unlike the Apple II. Commodore shared detailed specifications for its computers, unlike the TI-99/4A, which focused on casual users. Early C64 sales were slow due to limited software, reliability problems with the PLA chip, and a shortage of 1541 disk drives. By 1983, software availability improved, and sales increased.
Commodore sold the C64 through dealers, department stores, toy stores, and college bookstores. The C64 had an RF modulator, allowing it to connect to any TV, competing with video game consoles like the Atari 2600. It also supported composite video output for sharper images on monitors. The C64’s NTSC output included separate luminance and chroma signals, compatible with the Commodore 1702 monitor, providing better video quality than composite signals.
Commodore’s low prices for the C64 contributed to the video game crash of 1983. In January 1983, Commodore offered a $100 rebate for trading in other consoles or computers. Some retailers sold the Timex Sinclair 1000 for as little as $10 with a C64 purchase. This deal allowed customers to send the TS1000 to Commodore, collect the rebate, and keep the 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 and used a simplified version of the hardware later used in the C64. The MAX was stopped selling shortly after it was released 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 essentially a C64 paired with a green monochrome monitor in a PET-style case. Schools preferred the PET’s single metal unit over the C64’s separate parts, which were easier to break, damage, or steal. Schools also preferred the Apple IIe over the Educator 64 because the Apple IIe had more software and hardware options. The Educator 64 was produced 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 monochrome ("green screen") displays, but the SX-64 included a 5-inch color cathode ray tube (CRT) and one built-in 1541 floppy disk drive. Although advertisements claimed the SX-64 would have two 1541 drives, only one was included when it was released. The other drive was replaced with a floppy disk storage slot. Unlike most C64 models, the SX-64 did not have a datasette connector, so it could not use external cassette tapes.
Two designers at Commodore, Fred Bowen and Bil Herd, worked to improve the Plus/4. They aimed to create better successors to the C64—the Commodore 128 and 128D (1985)—that would avoid the Plus/4’s flaws. These successors included features like a BASIC programming language with graphics and sound commands, an 80-column display, and full CP/M compatibility. Bowen and Herd secretly decided to make the Commodore 128 compatible with the C64 without management approval. They kept this decision 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 publicly, raising expectations for C64 support. To meet these expectations, the C128 was redesigned to include a separate "64 mode" that used a complete C64 environment.
The C64’s designers originally planned to release a new wedge-shaped case within a year of its launch, but this change did not happen. In 1986, Commodore released the 64C, which was functionally identical to the original C64. The 64C was nicknamed the Breadbin 64 after the 64C’s release. Its design was updated to match the sleeker style of 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 keyboard keys instead of the front. The sound chip (SID) was upgraded to the MOS 8580, reducing its voltage from 12V to 9V. This change affected how filters and volume controls worked, making some music and sound effects sound different. The 64 KiB RAM was reduced 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 also combined color RAM into the same chip. The smaller design made it impossible to add some internal expansions, like a floppy-speeder. In the United States, the 64C was often sold with the third-party GEOS graphical user interface (GUI) and software for accessing Quantum Link. The 1541 drive was redesigned as the 1541C. Later, a smaller 1541-II model and the 800 KB 3.5-inch microfloppy 1581 were introduced.
In 1990, the C64 was sold as a game console called the C64 Games System (C64GS), with most external connections 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 instructed users to insert a cartridge. Designed to compete with the Nintendo Entertainment System and Sega’s Master System, the C64GS had very low sales compared to its rivals. It was another failure for Commodore and was never sold outside Europe. The C64GS lacked a keyboard, so software requiring a keyboard could not be used.
In 1990, Commodore began developing an advanced successor to the C64, the Commodore 65 (also called the "C64DX"), but the project was canceled in 1991 by Commodore’s chairman, Irving Gould. The C65 had impressive specifications for an 8-bit computer, matching those of the 16-bit Apple IIGS. For example, it could display 256 colors on the screen, while OCS-based Amigas could only show 64 colors in HalfBrite mode (32 colors and half-bright transformations). No specific reason was given for the C65’s cancellation, but it would have competed with Commodore’s lower-end Amigas and the Commodore CDTV.
Software
In 1982, the C64's graphics and sound were as good as the Atari 8-bit computers and much better than the Apple II. The C64 is often credited with starting the demoscene, a group of people who create computer demonstrations. It is still used today in the demoscene, especially for music. Its SID sound chip was even used in special sound cards for personal computers and in the Elektron SidStation synthesizer. Even though other computers later improved, the C64 stayed a strong competitor to video game consoles like the Nintendo Entertainment System (NES) and Master System. This was partly because the C64 already had a large collection of software available.
In the UK, many people had lower incomes, and the ZX Spectrum was very popular. Because of this, most C64 software there used cassette tapes. Few cassette-based C64 programs were released in the US after 1983. In North America, diskettes were the main way to distribute software. The C64 had a cartridge slot, but it was mostly used in the first two years it was sold in the US. Once disk drives became more affordable and reliable, the cartridge slot became less useful. A few games in the PAL region used special cartridges to work around the 16 KiB memory limit.
Like many home computers from the early 1980s, the C64 came with a BASIC interpreter stored in its memory. The KERNAL, input/output functions, and operations for tape and disk drives were controlled through special BASIC commands. The disk drive had its own microprocessor and memory, similar to earlier systems like the CBM/PET and Atari 400 and 800. This meant the C64 did not need extra memory for a disk operating system, unlike 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 few users would need the disk-related features of BASIC 4.0. Using BASIC 2.0 made it easier for users of the VIC-20 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 "PEEK and POKE" commands to directly control the graphics and sound chip. To add more features, Commodore created two cartridge-based extensions: 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 made. Most commercial C64 software was written in assembly language, which allowed for faster performance and better use of memory. Some games, especially adventure games, used high-level scripting languages and combined BASIC with machine code.
Many third-party operating systems were developed for the C64. These included versions of GEOS, WiNGS OS, LUnix, Contiki, and others. Some of these systems required hardware upgrades to the original C64. A version of CP/M was also available, but it needed an external Z80 processor and had poor performance. CP/M software for the C64 and C128 was limited because few companies created software for these systems.
During the 1980s, the C64 was used to run bulletin board systems (BBS) with software like Punter BBS, Bizarre 64, and others. These systems sometimes shared cracked software. As late as December 2013, 25 BBS systems were still active and accessible through the Telnet protocol. Major online services, such as Compunet, CompuServe, The Source, and Minitel, were available during this time. These services often required custom software, modems, and charged by the minute for online time. Quantum Link (Q-Link) was an online service for the C64 and C128 from 1985 to 1994. It was later renamed America Online and continued to serve IBM PC and Apple Macintosh users.
The first graphical, character-based interactive environment was called Club Caribe. Originally named Habitat, it was created by LucasArts for Q-Link users on the C64. Players could chat, exchange items, and interact with others. Though the game’s world was simple, it was groundbreaking for its use of online avatars and combining chat with graphics. In the late 1980s, online graphics were limited by slow modem speeds, often as low as 300 bits per second. Habitat’s graphics were stored on floppy disks, avoiding the need to transfer them over the network.
Hardware
The C64 uses an 8-bit MOS Technology 6510 microprocessor that is very similar to the 6502 but has some differences, such as three-state buses, a different pin arrangement, slightly different clock signals, and other small changes for this use. It also has six I/O lines on unused pins of the 40-pin IC package. These lines are used for two tasks: switching the computer’s read-only memory (ROM) in and out of the processor’s address space, and controlling the datasette tape recorder. The C64 has 64 KB of 8-bit dynamic RAM, 1 KB of 4-bit static color RAM for text mode, and 38 KB available for Commodore BASIC 2.0 when the computer starts. There is 20 KB of ROM, which includes the BASIC interpreter, the KERNAL, and the character ROM. Since the processor can only access 64 KB at a time, the ROM is mapped into memory, and only 38,911 bytes of RAM (plus 4 KB between the ROMs) are available at startup. Most "breadbin" C64 models used 4164 DRAM with eight chips totaling 64 KB of system RAM. Later models with Assy 250466 and Assy 250469 motherboards used 41464 DRAM (64K×4) chips, which stored 32 KB per chip (so only two were needed). Because 4164 DRAMs are 64K×1, eight chips are required to make a full byte; the computer will not work without all of them. The first chip holds Bit 0 of memory, the second chip holds Bit 1, and so on.
The C64 checks its RAM when it starts up. If a RAM error is found, the amount of free BASIC memory will be less than the usual 38,911. If the faulty chip is in lower memory, an error message "?OUT OF MEMORY IN 0" appears instead of the normal BASIC startup screen.
The C64 uses a complex memory-banking system. The default setting on startup maps the BASIC ROM at $A000–$BFFF and the screen editor (KERNAL) ROM at $E000–$FFFF. RAM under the system ROMs can be written to but not read back without swapping out the ROMs. Memory location $01 contains a register with control bits for enabling or disabling the system ROMs and the I/O area at $D000. If the KERNAL ROM is swapped out, BASIC is also removed. BASIC cannot function without the KERNAL, as BASIC often uses KERNAL routines, and part of the BASIC ROM code is in the KERNAL ROM.
The character ROM is normally hidden from the CPU. It can be mapped into $D000–$DFFF, making it visible to the CPU. This requires swapping out the I/O registers, so interrupts must first be disabled. Removing I/O from the memory map frees $D000–$DFFF as RAM.
C64 cartridges are mapped into specific ranges in the CPU’s address space. The most common auto-starting cartridges require a string at $8000 containing "CBM80" followed by the program’s start address. Some 1982 cartridges used Ultimax mode, a feature from the failed MAX Machine. These cartridges mapped into $F000, displacing the KERNAL ROM. If Ultimax mode is used, the programmer must provide code for handling system interrupts. The cartridge port has 16 address lines, allowing access to the computer’s entire memory space if needed. Disk and tape software usually loads at the start of BASIC memory ($0801) and uses a small BASIC stub (like 10 SYS(2064)) to jump to the program. While no Commodore 8-bit machine except the C128 can automatically boot from a floppy disk, some software overwrites BASIC vectors to start automatically instead of requiring the user to type "RUN."
About 300 cartridges were released for the C64, mostly during its first 2½ years on the market. After that, most software required more than 16 KB, which limited cartridge use. One notable third-party expansion was the Power Cartridge, developed by Kolff Computer Supplies (KCS). It added a BASIC toolkit, a machine code monitor, a reset button, and fastload routines that sped up cassette and disk access (up to 10× and 6×). Popular in the Benelux region, it was used for productivity and programming. Larger companies like Ocean Software later released games on bank-switched cartridges to overcome the 16 KB limit.
Commodore did not include a reset button on its computers until the CBM-II line, but third-party cartridges had one. A soft reset can be triggered by jumping to the CPU reset routine at $FCE2 (64738). Some programs use this as an exit feature, though it does not clear memory.
The KERNAL ROM had three versions, mainly to fix bugs. The first version was used only on 326298 motherboards (early models) and could not detect NTSC or PAL VIC-II chips. The second version was used from late 1982 through 1985. The final version was introduced on the 250466 motherboard (late breadbin models with 41464 RAM) and used in all C64Cs. The 6510 CPU runs at 1.023 MHz (NTSC) and 0.985 MHz (PAL), slower than some competitors like the Atari 800 (1.79 MHz). Performance can be slightly improved by disabling the VIC-II’s video output through a register write. This is often used by fast loaders and the KERNAL cassette routine to maintain standard CPU timing.
The restore key is connected directly to the CPU’s NMI line and triggers an NMI if pressed. The KERNAL checks if the run/stop key is also pressed; if not, it ignores the NMI. Run/stop-restore normally resets I/O registers to their default state in BASIC but does not clear memory or reset pointers, leaving BASIC programs untouched. Machine-language software often disables run/stop-restore by remapping the NMI vector to a dummy RTI instruction. The NMI can also be used for extra interrupts, but accidental presses may cause system issues.
The C64 kept the VIC-20’s DE-9 Atari joystick port and added another, allowing Atari-style controllers. Joysticks are read from registers at $DC00 and $DC01. Most software uses port
Clones and other reuse of the Commodore 64 name
C64 clones are computers that copy the features of the Commodore 64. In mid-2004, after being off the market for over 10 years, Tulip Computers (which owned the Commodore brand since 1997) released the C64 Direct-to-TV (C64DTV). This was a TV game system that used a joystick and had 30 games stored in its memory. Designed by Jeri Ellsworth, a self-taught computer designer who also created the C-One C64 version, the C64DTV was similar to other small game consoles inspired by the Atari 2600 and Intellivision. It was sold on QVC in the United States during the 2004 holiday season.
In 2015, Individual Computers made a Commodore 64-compatible motherboard called the C64 Reloaded. This was a redesigned version of the original Commodore 64 motherboard, number 250466, with new features. The motherboard could be placed into an existing empty C64 or C64C case. It was made in limited numbers and had special connectors for custom chips. It included switches to use different versions of the VIC-II and SID chips and could switch between PAL and NTSC video systems. It also had options to choose different memory chips, a reset button on the power switch, and an S-Video port instead of the original TV modulator. The motherboard used a DC-to-DC converter powered by 12 V DC from a power adapter, instead of the original, less reliable power supply.
In 1998, the Commodore 64 name 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 memory, a 3.5-inch floppy disk drive, a 56k modem, and a PC Card. Although it had the Commodore 64 name, it looked different and was only compatible with the original through included software that mimicked the original system. In 2011, Commodore USA, a company licensed to use the Commodore brand, began selling C64x clones. These computers had cases similar to the original C64 but used x86 technology and were not compatible with the original Commodore 64.
Several Commodore 64 games were made available on the Nintendo Wii’s Virtual Console in Europe and North America. These games were removed from the service in August 2013.
A British company called Retro Games made two unofficial Linux-based devices that mimic the Commodore 64: THEC64 Mini in 2018 and the full-size THEC64 in 2019. Retro Games did not use any Commodore trademarks, so the devices are named without a space between "The" and "C64." This also means the original Commodore key on the keyboard was replaced with a THEC64 key.
THEC64 Mini is a small, decorative version of the Commodore 64. It has two USB ports, one HDMI port, and a mini USB connection for power. The keyboard does not work, and the system is controlled using a included THEC64 joystick or a separate USB keyboard. It uses the VICE emulator, which can also load extra software.
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 added features like HDMI output and the ability to load software over USB, Wi-Fi, or Ethernet.
Emulators
Commodore 64 emulators include the open source VICE, Hoxs64, and CCS64. An iPhone app was also released with a compilation of C64 ports.
The Commodore PET, introduced in July 2015, was an Android smartphone with Commodore 64 and Amiga emulation built-in.