Precise Calculator is a free open source scientific calculator for Windows.

Features:
News: I've joined the "ReactOS Open Source Program". ReactOS® is a free open source operating system which is binary compatible with Windows®. Many excellent open source applications can be easily installed from ReactOS Desktop App Manager.
If you like the Precise Calculator, maybe you should try other freeware programs too: Sokoban, Solitaire, Gomoku game, triangular Mines, Color Sudoku, Tiny Player, HotkeyP. You can find them on my homepage.