🧮 Calculators
Scientific Calculator with Tape History
A real math engine (no eval()), a running tape you can edit and recalculate, unit-aware and base conversions, plus graphing, equation solving, matrices, and statistics.
Drag to pan, scroll/pinch to zoom. Click on a curve to trace values.
Matrix A
Matrix B
Frequently asked questions
Why does my trig answer look wrong?
The most common cause is being in the wrong angle mode. sin(30) equals 0.5 in DEG mode but equals about -0.988 in RAD mode, since 30 radians is a very different angle. Check the DEG/RAD/GRAD toggle at the top — it's the single most common calculator mistake.
How do I use the tape?
Every calculation you run appears on the tape automatically. Click a past result to insert it into your current expression, click a past expression to edit and re-run it, or edit any number directly in the tape — everything recalculates in order, so later lines update too.
Does it work offline?
Yes. After your first visit, a service worker caches the app so it opens and works with no internet connection, including the tape, memory, and variables.
How do I calculate percentages?
Use the dedicated percentage buttons to avoid ambiguity: "200 + 10%" correctly gives 220 (10% of 200 added on), not 200.1. There are also direct buttons for "what % is A of B" and "A is B% of what".