The first personal computer was the Altair 8800, released in January 1975

The Altair 8800 arrived as a kit you had to assemble yourself. It cost $395 (or $1,075 if you bought it pre-built), came with no keyboard or monitor, and displayed output as blinking lights on the front panel. Despite those limitations, it is widely recognized as the first computer designed and marketed for individual use rather than businesses or institutions.

The Altair was built by Micro Instrumentation and Telemetry Systems (MITS), a company in Albuquerque, New Mexico. The machine used an Intel 8080 processor and came with 256 bytes of memory—roughly enough to store a few sentences of text. It appeared on the cover of Popular Electronics magazine in January 1975, and that visibility sparked genuine public interest. Within months, MITS had more orders than it could fill.

What made the Altair significant was not its power but its price and its target audience. Earlier computers filled entire rooms, cost hundreds of thousands of dollars, and were operated by trained technicians. The Altair was small enough to sit on a desk and cheap enough that a hobbyist or small business could actually buy one.

Key Takeaways

  • The Altair 8800, released in January 1975 by MITS, is recognized as the first personal computer sold to the general public.
  • It cost $395 as a kit or $1,075 assembled, used an Intel 8080 processor, and had 256 bytes of memory with no built-in keyboard or display.
  • The Altair's appearance in Popular Electronics magazine created when ready demand and launched the personal computer industry.
  • Earlier computers existed but were room-sized machines operated by professionals; the Altair was the first designed for individual ownership and use.

Why the Altair matters more than earlier machines

Computers existed before 1975. The ENIAC, built in 1946, was a general-purpose electronic computer. The IBM System/360, introduced in 1964, was programmable and powerful. But both were institutional machines—they lived in universities, government offices, and large corporations. You did not own one. You submitted your work to an operator, waited for results, and paid by the hour.

The Altair changed the equation. It was designed from the start to be owned and operated by one person. You could keep it at home. You could experiment with it without asking permission. You could write programs for it and run them when ready. That shift—from computer as shared institutional resource to computer as personal tool—is why the Altair marks the beginning of the personal computer era, even though it was crude by later standards.

What happened when ready after the Altair

The Altair's success attracted competitors and entrepreneurs. In 1976, Steve Jobs and Steve Wozniak released the Apple I, a computer that came fully assembled and included a keyboard and monitor connection. That same year, the Commodore PET and the TRS-80 from Radio Shack arrived. These machines were easier to use than the Altair and came with software already installed.

By 1977, the personal computer market had shifted from hobbyist kits to consumer products. The Apple II, released in June 1977, became the first mass-market personal computer. It had color graphics, a built-in keyboard, and slots for expansion cards. It also had software: VisiCalc, the first spreadsheet program, arrived in 1979 and made the Apple II indispensable to small business owners and accountants.

The IBM PC, released in August 1981, brought personal computers into corporate offices. It was not the most powerful or the cheapest machine available, but IBM's reputation and its decision to use an open architecture (allowing other companies to make compatible parts and software) made it the standard. Within a few years, "IBM-compatible" computers dominated the market.

The difference between "first" and "most important"

The Altair was first, but it was not the most important early personal computer. The Apple II was more influential because it was easier to use and had better software. The IBM PC was more influential because it became the industry standard. But neither would have existed without the Altair proving that a market for personal computers existed at all.

When historians and engineers talk about "the first personal computer," they mean the Altair because it was the first machine marketed and sold as a personal computer—a device for individual use rather than institutional use. Earlier machines were more powerful or more practical, but they were not personal computers in that sense.

How the Altair actually worked

The Altair had no screen. To see what it was doing, you read the lights on its front panel—a row of LEDs that blinked in patterns representing binary data. To enter a program, you flipped switches on the front panel to input machine code directly. It had no keyboard, no mouse, no operating system in the modern sense.

Despite this, people bought it. Hobbyists and engineers saw potential. Two young programmers, Bill Gates and Paul Allen, wrote a version of the BASIC programming language for the Altair, making it possible to write programs without learning machine code. That software made the Altair much more useful, and it also launched Microsoft.

Why the Altair was possible in 1975

The Altair arrived at a specific moment in technology history. The Intel 4004, the first microprocessor, was released in 1971. By 1975, microprocessors were powerful enough and cheap enough to be the heart of a small, affordable computer. Memory chips had also become cheaper and more compact. The combination of these advances made the Altair feasible.

At the same time, there was an audience ready for it. The hobbyist electronics community was already large and active. People built radios, amplifiers, and other devices from kits. A computer kit appealed to the same mindset. MITS recognized this audience and marketed the Altair directly to them through Popular Electronics, a magazine read by electronics enthusiasts.

Frequently Asked Questions

Was the Apple I the first personal computer?

No. The Apple I came out in 1976, about a year after the Altair 8800. The Apple I was a better machine in many ways—it came fully assembled and included a keyboard—but the Altair arrived first and created the market that Apple entered.

Did IBM invent the personal computer?

No. IBM released the IBM PC in 1981, six years after the Altair. IBM did not invent the personal computer, but the IBM PC became the dominant standard because of IBM's reputation and the open architecture that allowed other companies to make compatible machines and software.

Could you actually use the Altair for anything practical?

Not much by modern standards. It had no keyboard, no screen, and 256 bytes of memory. But hobbyists used it to learn programming, experiment with electronics, and build straightforward applications. Once BASIC was available, it became more practical for writing and running small programs.

Why is the Altair considered the first personal computer and not earlier machines?

Earlier computers like the ENIAC and IBM System/360 were more powerful, but they were designed for institutions and operated by trained professionals. The Altair was the first computer marketed and sold to individuals for personal use, which is why it marks the start of the personal computer era.

How much would the Altair cost in today's money?

The $395 kit price in 1975 is roughly equivalent to $2,200 in 2024 dollars, accounting for inflation. The $1,075 pre-built price would be about $6,000 today. That made it expensive but within reach for hobbyists and small businesses, which is why it sold.