Sinclair Executive.

Launched in the summer of 1972, the Executive was the first Sinclair calculator, and by a clever circuit design was the world's first calculator to be powered by button cells. This allowed it to be incredibly thin for the time at 9mm, 0.4".

This is a featured calculator.

Sinclair Cambridge.

The first Sinclair Cambridge model was introduced in summer 1973. There followed a range of a dozen or so models and variations.

This is a featured British calculator.

Sinclair Scientific.

By a clever choice of algorithms and elctronics Sinclair was able to produce a very small, low-cost, Scientific calculator, using RPN (Reverse Polish Notation).

This is a featured British calculator.

Sinclair Oxford 200.

There are several models in the Oxford range, and some were made in an LED version and also, probably later, in a VFD (Vacuum Fluorescent Display) version.

This is a featured British calculator.

Sinclair Sovereign.

By 1976, with the market flooded by many cheap models, Sinclair was struggling to make a profit from its calculators. The Sovereign was one of the last Sinclair models, and was a move by the company to a very stylish, tiny, high-quality model that it could sell for a higher price.

This is a featured British calculator.

Sinclair Wrist Calculator.

This was the last calculator designed under Clive Sinclair, in 1977.

Calculator Companies