Does my history sync across devices?

No. History is stored only in your browser's local storage on this device. There is no account system and the data never leaves your machine.

How accurate is the arithmetic?

Calculations use JavaScript's IEEE-754 double-precision floats, which are exact for integers up to 2^53 and roughly 15–17 significant digits for decimals. For typical everyday use this is more than enough; for cryptographic-grade or financial-regulation work, use a fixed-point or decimal library instead.

Why does '2 + 3 × 4' give 20 instead of 14?

This calculator applies each operator immediately to the running total — the same behaviour as classic physical pocket calculators. There is no operator-precedence resolution. For PEMDAS-style math with parentheses and exponents, switch to the scientific calculator.

Yes. Tap or click on the result display to select it, then copy with Cmd/Ctrl-C. The history panel also exposes individual entries for copy.

Does the calculator work offline?

Once the page is loaded, the calculator runs entirely in your browser — no internet connection is needed to compute, save history, or change themes. Bookmark the page for quick offline access.

Basic calculator

Fast arithmetic with history and keyboard support.

A fast, free basic arithmetic calculator for everyday use — addition, subtraction, multiplication, and division — with full keyboard support, a running history stored locally on your device, and dark mode for late-night work. Designed for quick mental-math sanity checks and simple budgeting without the overkill of a spreadsheet.

Tips for using the basic calculator

Type directly with your keyboard. Number keys 0–9, the operators +, −, *, /, the decimal point, Enter (or =) to compute, and Backspace to delete the last digit are all wired up. Escape clears the current expression; pressing C twice clears the entire memory.

Each completed calculation is appended to the history panel on the right. Click any previous entry to recall it as the current expression — useful when you want to chain a follow-up operation on a recent result.

History is stored only in your browser's local storage on this device. It never leaves your machine, never syncs to a server, and is cleared if you wipe your browser data. There is also a one-click 'Clear history' button at the top of the panel.

On mobile, the on-screen keypad responds to taps with the same key behaviour. The order-of-operations on this calculator is strictly left-to-right — for parentheses, exponents, or precedence-sensitive math, use the scientific calculator instead.

How the basic operators behave

Addition (+) and subtraction (−) work as expected for both integers and decimals.

Multiplication (× or *) and division (÷ or /) follow left-to-right evaluation. Pressing '2 + 3 × 4 =' on this calculator yields 20, not 14 — because each operator is applied immediately to the running total.

Division by zero displays 'Error' and clears the operand. The next key resets the calculator.

Decimal precision uses JavaScript's IEEE-754 doubles, accurate to about 15 significant digits. Use the scientific calculator for higher-precision work.

Frequently asked questions

Does my history sync across devices?: No. History is stored only in your browser's local storage on this device. There is no account system and the data never leaves your machine.
How accurate is the arithmetic?: Calculations use JavaScript's IEEE-754 double-precision floats, which are exact for integers up to 2^53 and roughly 15–17 significant digits for decimals. For typical everyday use this is more than enough; for cryptographic-grade or financial-regulation work, use a fixed-point or decimal library instead.
Why does '2 + 3 × 4' give 20 instead of 14?: This calculator applies each operator immediately to the running total — the same behaviour as classic physical pocket calculators. There is no operator-precedence resolution. For PEMDAS-style math with parentheses and exponents, switch to the scientific calculator.
Can I copy a result?: Yes. Tap or click on the result display to select it, then copy with Cmd/Ctrl-C. The history panel also exposes individual entries for copy.
Does the calculator work offline?: Once the page is loaded, the calculator runs entirely in your browser — no internet connection is needed to compute, save history, or change themes. Bookmark the page for quick offline access.