The first computer depends on how you define "computer"

There is no single answer to when the first computer was made, because the word "computer" has meant different things at different times. If you mean a machine that performs calculations automatically, the Analytical Engine, designed by Charles Babbage in 1837, is often called the first computer — though it was never fully built during his lifetime. If you mean an electronic machine that could run different programs, the ENIAC (Electronic Numerical Integrator and Computer), completed in 1946 at the University of Pennsylvania, is usually credited as the first general-purpose electronic computer. If you mean a machine small enough to sit on a desk, that came much later, in the 1970s and 1980s.

The reason for these different answers is that computers evolved gradually. Each machine built on the work of earlier inventors, and each one solved a problem the previous machine could not. Understanding which machine counts as "first" depends on what you think a computer actually is.

Key Takeaways

  • Charles Babbage designed the Analytical Engine in 1837, a mechanical machine that could perform different calculations based on punched cards, making it the ancestor of modern computers.
  • ENIAC, built in 1946, was the first electronic general-purpose computer and could solve many different types of problems without being rebuilt.
  • Early computers were enormous machines that filled entire rooms and consumed large amounts of electricity.
  • The transistor, invented in 1947, made computers smaller and faster, leading to the personal computers of the 1970s and 1980s.

Charles Babbage and the Analytical Engine (1837)

Charles Babbage, an English mathematician, designed the Analytical Engine in 1837. It was a mechanical device — made entirely of gears, levers, and wheels — that could perform arithmetic operations in any order based on instructions written on punched cards. This was revolutionary because earlier calculating machines could only do one type of operation, like addition or multiplication, but not both in sequence.

Babbage never completed the Analytical Engine during his lifetime, partly because the precision metalwork required was beyond the technology of the 1800s, and partly because he ran out of funding. However, his design included every essential feature of a modern computer: an input device (the punched cards), a memory to store numbers, a processor to perform operations, and an output device to display results. Ada Lovelace, a mathematician who worked with Babbage, wrote detailed notes about how the machine would work and is often credited as the first computer programmer.

Because the Analytical Engine was never built, some historians argue it should not count as the "first computer." Others say that a design counts, even if the machine itself was not constructed. Either way, Babbage's work laid the foundation for everything that came after.

ENIAC and the Electronic Era (1946)

The first electronic general-purpose computer was ENIAC, completed on February 14, 1946, at the University of Pennsylvania. It was built by John Mauchly and J. Presper Eckert as part of a U.S. Army project to calculate artillery firing tables during World War II. ENIAC was enormous — it weighed 30 tons, occupied 1,800 square feet of floor space, and used 18,000 vacuum tubes to perform calculations.

ENIAC could perform about 5,000 additions per second, which was thousands of times faster than any mechanical calculator. Unlike earlier machines, ENIAC could be reprogrammed to solve different problems by rewiring circuits and changing settings — a process that took days or weeks. This made it a true general-purpose computer rather than a machine built for one specific task.

The drawback was that ENIAC consumed 150 kilowatts of electricity and generated so much heat that it required a dedicated cooling system. It also broke down frequently because vacuum tubes burned out and had to be replaced. Despite these limitations, ENIAC proved that electronic computing was practical and launched the computer age.

The Transistor and Smaller Computers (1947 onward)

The invention of the transistor in 1947 at Bell Labs changed everything. Transistors were tiny electronic switches that could do the same job as vacuum tubes but used far less power, generated less heat, and were much more reliable. As transistors became cheaper and easier to manufacture, computers became smaller, faster, and more affordable.

By the 1960s, computers using transistors were common in universities, large corporations, and government agencies. They were still room-sized machines, but they were more practical than ENIAC. In the 1970s, the invention of the integrated circuit — which packed thousands of transistors onto a single chip — made personal computers possible. The Apple II, released in 1977, and the IBM Personal Computer, released in 1981, brought computing to homes and small offices.

Why the Answer Matters

The question "when was the first computer made" is not just a history question — it reflects how we think about what a computer is. If you define a computer as any machine that performs calculations, then the abacus (used for thousands of years) and mechanical calculators (from the 1600s onward) count. If you define it as a programmable machine that can solve many different problems, then Babbage's Analytical Engine is the answer. If you mean an electronic machine that actually existed and worked, then ENIAC is the answer.

Most computer scientists and historians use ENIAC as the starting point for the modern computer era, because it was the first machine that combined electronic speed with programmability and general-purpose capability. However, Babbage deserves credit for inventing the concept, even though he could not build it.

From Room-Sized Machines to Pocket Devices

The computers that existed from 1946 through the 1960s were so large and expensive that only governments, universities, and major corporations could afford them. A single computer might cost hundreds of thousands of dollars — in equivalent purchasing power, millions of dollars. Programming them required specialized training, and each machine needed a team of technicians to keep it running.

The transistor and integrated circuit changed this completely. By the 1980s, computers that were more powerful than ENIAC could fit on a desktop and cost a few thousand dollars. By the 2000s, computers were in most homes. A smartphone contains more computing power than ENIAC and costs a few hundred dollars.

Frequently Asked Questions

Was the first computer mechanical or electronic?

It depends on your definition. Babbage's Analytical Engine (1837) was mechanical and is often called the first computer in concept. ENIAC (1946) was the first electronic general-purpose computer that actually existed and worked. Most historians mark ENIAC as the beginning of the modern computer era.

Why did it take so long to build the first electronic computer?

Vacuum tubes, which made electronic computing possible, were not invented until the early 1900s. Even then, building a reliable electronic computer required solving many engineering problems — how to keep thousands of tubes from burning out, how to cool the machine, how to program it, and how to make it fast enough to be useful. ENIAC took years to design and build.

Could Babbage's Analytical Engine actually work if someone built it?

Yes. In 2002, a team at the Science Museum in London built a working model of part of Babbage's design using 19th-century materials and techniques. It performed calculations correctly, proving that Babbage's design was sound — the problem was that building it with the tools available in the 1800s was extremely difficult.

How much did ENIAC cost?

ENIAC cost about $500,000 to build, which is roughly $8 million in equivalent purchasing power. This was a huge investment, but the U.S. Army considered it worthwhile because the machine could calculate in hours what would take human mathematicians weeks to do by hand.