Excluding the abacus or slide rule, the first mechanical calculator was invented by French inventor, Blaise Pascal in 1642. It could add or subtract two numbers or divide and multiply by repetition, using geared wheels.
In 1820, a device in a patent filed in France by Thomas de Colmar, became the first commercially viable counting machine. The design was copied by around 20 companies across Europe. In 1877, the Grant Mechanical Calculating Machine was born and in 1886, the P100 Burroughs Adding Machine arrived. It was not until 1948 that a pocket-sized calculator was invented and came in the form of the Curta calculator.
It was not until the 1960s and the advent of electronic devices that the electronic calculator came to be. ANITA (A New Inspiration To Arithmetic/Accounting) was the first all-electric desktop calculator and was released in 1961. They sold for about $1,000 when they were released that, in 2014, is nearly $8,000 after accounting for inflation. In 1965, the ELKA 22 was produced in Bulgaria and was the first calculator in the world to have a square root function. The end of bulky calculators did not happen until 1968 when Texas Instruments released the Cal Tech, the first hand-sized calculator that printed the results to paper.