The Altair 8800 arrived in 1975 as the first computer for individual use

The Altair 8800, released in January 1975, is widely recognized as the first personal computer. It was built by Micro Instrumentation and Telemetry Systems (MITS) in Albuquerque, New Mexico, and sold as a kit for $397—roughly $2,300 in equivalent dollars. The machine had no keyboard, no monitor, and no disk drive. Users entered commands by flipping switches on the front panel and read results from blinking lights.

The Altair ran on an Intel 8080 processor and came with 256 bytes of memory—not kilobytes, bytes. Despite these severe limits, it proved there was a market for computers that individuals could own and tinker with rather than rent time on machines the size of refrigerators. The Altair's arrival sparked the personal computer revolution and attracted two young programmers named Bill Gates and Paul Allen, who wrote the first version of BASIC software for it.

Key Takeaways

  • The Altair 8800 launched in January 1975 as the first personal computer, built by MITS and sold as a kit for $397.
  • The machine had 256 bytes of memory, an Intel 8080 processor, and no keyboard or monitor—users toggled switches and read blinking lights.
  • The Altair's success proved individuals would buy computers for their own use, which led directly to the Apple II and IBM PC.
  • Bill Gates and Paul Allen wrote BASIC software for the Altair, which became their first major business venture before Microsoft.

What made the Altair different from earlier computers

Before 1975, computers were institutional machines. Universities, governments, and large corporations owned them. They occupied entire rooms, cost hundreds of thousands of dollars, and required trained operators and climate control. A person could not buy one or keep one at home.

The Altair changed that equation by being small enough to fit on a desk, affordable enough for hobbyists to save up for, and straightforward enough that an amateur could understand how it worked. It was not the first computer to be called "personal"—that label had been used before—but it was the first one people actually wanted to own and use themselves. The kit format meant buyers had to assemble it, which appealed to electronics enthusiasts who enjoyed building things.

How the Altair led to the computers we use today

The Altair's success created a market that attracted entrepreneurs. Steve Jobs and Steve Wozniak saw the Altair and decided to build something easier to use. In 1976, they released the Apple I, which had a keyboard and could connect to a television. In 1977, Apple released the Apple II with a color display and a disk drive—features that made it the first personal computer most people could actually use without technical training.

IBM entered the market in 1981 with the IBM PC, which used an Intel processor and an operating system called MS-DOS written by Microsoft. The IBM PC became the standard for business, and its design was copied by other manufacturers, which drove prices down and spread personal computers into homes and offices worldwide. Every desktop and laptop computer today traces its lineage back to the Altair's proof that individuals would buy computers.

The Altair's technical limits and what users could actually do

The Altair 8800 had 256 bytes of memory in its base configuration, though users could expand it to 64 kilobytes—a massive upgrade at the time. The processor ran at 2 megahertz. There was no permanent storage except paper tape. Programs had to be entered by hand, one instruction at a time, using the front-panel switches. A single mistake meant starting over.

What could you do with it? Write straightforward programs in BASIC. Perform calculations. Run logic puzzles and games. Store data on paper tape and load it back later. The machine was useful for learning how computers worked and for solving specific math problems, but it was not practical for everyday tasks like word processing or spreadsheets. Those applications came later, once computers had keyboards, displays, and disk storage.

Why 1975 and not earlier

The Intel 8080 processor, released in 1974, was the first chip powerful enough and cheap enough to make a personal computer practical. Earlier processors existed but were either too expensive or too weak. The 8080 cost around $200 and could run useful programs. At the same time, memory chips had become affordable enough that a hobbyist could buy enough RAM to make the machine worth using.

MITS founder Ed Roberts recognized this moment and designed the Altair around the 8080. He advertised it in Popular Electronics magazine in December 1974, and the response was overwhelming. The company received thousands of orders before the machine was even in production. That surge of interest proved the market existed and triggered a wave of competitors and improvements that became the personal computer industry.

Other early contenders and why the Altair gets the credit

The Apple I, released in 1976, came close to the Altair's launch date and was arguably more usable. The Commodore PET and TRS-80 both arrived in 1977 and were easier for non-technical users. However, the Altair came first and created the market that made those later machines possible. It was the proof of concept that changed the industry's direction.

Some people point to earlier machines like the IMSAI 8080 or the Sphere 1, but these came after the Altair and were direct responses to its success. The Altair was the first to demonstrate that a small, affordable computer could attract a large audience of enthusiasts willing to buy and build them. That distinction is why it holds the title of first personal computer.

Frequently Asked Questions

Did the Altair 8800 have a screen?

No. The Altair had no monitor or display. Users entered data by flipping switches on the front panel and read the results from rows of blinking lights. To see actual text or graphics, you needed to connect it to a separate device, which most hobbyists did not have.

Could you type on the Altair 8800?

The base Altair had no keyboard. You entered commands by toggling switches. Later, users could add a keyboard as an optional accessory, but it was not standard. The Apple II, released two years later, came with a keyboard built in, which made it far more practical for everyday use.

How much did the Altair 8800 cost?

The kit version cost $397 in 1975, which is roughly $2,300 in equivalent dollars. An assembled version cost more. For comparison, a new car cost around $5,000 at the time, so the Altair was expensive but not out of reach for serious hobbyists and small businesses.

What happened to MITS and the Altair?

MITS sold thousands of Altairs and became successful, but the company faced competition from Apple, Commodore, and IBM. By the early 1980s, MITS was struggling. Commodore bought the company in 1981, but the Altair brand was discontinued as newer, more powerful machines took over the market.

Did Bill Gates and Paul Allen make money from the Altair?

Yes. They wrote BASIC software for the Altair and licensed it to MITS. This deal gave them their first significant revenue and helped launch Microsoft. Gates famously dropped out of Harvard to focus on the business, betting that personal computers would become widespread—a bet that paid off enormously.