Pocket calculator

The pocket calculator emerged from an intense race between Japanese and American electronics companies, driven by the convergence of LED displays and the 'calculator on a chip.' In early 1971, pocket-sized computing devices became possible, democratizing arithmetic and eliminating the slide rule from engineering classrooms worldwide.

The adjacent possible required three technological threads to merge. First, integrated circuits had been shrinking calculator logic from room-sized machines to desktop devices throughout the 1960s. Second, LED (light-emitting diode) displays could show digits using far less power than vacuum fluorescent displays. Third, the race to put an entire calculator on a single chip was reaching its climax.

The breakthrough came in early 1971 when Mostek announced the MK6010L—the first 'calculator on a chip.' This single integrated circuit contained all the logic needed for a four-function calculator. Two days later, Texas Instruments announced it was completing its own single-chip calculator, available off-the-shelf by June. The race was on.

Busicom (Nippon Calculating Machine Corporation) won. The Busicom LE-120A 'HANDY,' using the Mostek MK6010L chip, was the world's first true pocket calculator—small enough to fit in a shirt pocket—and the first with an LED display. It went on sale in Japan in early 1971. Sharp followed closely with the EL-8 in January 1971, which approached pocket size but wasn't quite there.

The connection to the microprocessor was direct. Intel had been commissioned by Busicom to create a custom chip for their calculators. The result—the Intel 4004, released in November 1971—became the world's first commercially available microprocessor. Intel bought back the rights and began selling the chip independently, launching the microprocessor revolution.

In America, the Bowmar 901B (nicknamed 'The Bowmar Brain') became the first American-made pocket calculator in autumn 1971. It measured 5.2 by 3.0 by 1.5 inches, performed four functions with an eight-digit red LED display, and sold for $240 (about $1,800 in 2024 dollars). Canon's Pocketronic, developed with Texas Instruments, had debuted in Japan in April 1970 at $395, reaching the US in February 1971 at $345.

The cascade was swift and brutal. Prices collapsed as competition intensified—from $240 in 1971 to under $10 by the late 1970s. By 1975, Texas Instruments was selling basic calculators for $25. The slide rule, the engineer's constant companion for centuries, became obsolete within a decade. Scientific pocket calculators followed, then programmable calculators, then handheld electronic games using the same miniaturization technologies.

By 2026, the standalone pocket calculator has largely been absorbed into smartphones. But its 1971 emergence marked the moment when personal computing became truly personal—a device you could carry in your pocket that performed calculations once requiring logarithm tables or mechanical adding machines.