What year was the first calculator made ?
The first American - made pocket - sized calculator , the Bowmar 901B ( popularly referred to as " The Bowmar Brain " ) , measuring 5.2 × 3.0 × 1.5 in ( 131 × 77 × 37 mm ) , came out in the Autumn of 1971 , with four functions and an eight - digit red LED display , for $ 240 , while in August 1972 the four - function Sinclair Executive became the first slimline pocket calculator measuring 5.4 × 2.2 × 0.35 in ( 138 × 56 × 9 mm ) and weighing 2.5 oz ( 70g ) .