The most reliable option for most users is the official by Microsoft. It is pre-installed on Windows 10 and 11, but if it's missing or you need to update it, you can find it on the Microsoft Store .
If the default app doesn't meet your needs, several powerful alternatives are available for download: GeoGebra Calculators and Apps - Free Downloads
Handles complex math like trigonometry, exponents, and order of operations.
Perfect for basic arithmetic like addition and multiplication.
Allows you to visualize equations and plot functions directly on a coordinate plane.