desktop calculator
A computing term for a calculator designed to sit on a desk, as opposed to a pocket calculator or software calculator.
In accounting work, a desktop calculator is still used sometimes.
電卓 is the common everyday word for an electronic calculator, often pocket-sized. 卓上計算器 is more specific to a desktop model and sounds more technical.
Compound of 卓上 (desktop) + 計算器 (calculator).