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A scientific calculator that runs locally

The calculator parses each expression with mathjs, so you can mix the on-screen buttons with the keyboard, group with parentheses, and chain operations. Results, history, and the constants list all stay in the browser tab.

1. Modes and display

• DEG / RAD. Switches angle mode for sin, cos, tan and their inverses. Set this before evaluating trig expressions; the toggle does not retroactively recompute history.
• History. Opens the last twenty entries. Tapping a row reloads its expression and result so you can edit and re-run.
• Display. The top line shows the current expression; the larger line shows the result or an Error message. The copy button next to the result copies the value to the clipboard.

2. Buttons that need a hint

• x², √, xʸ, ʸ√x. Power and root shortcuts. ʸ√x inserts nthRoot(, so type the radicand, a comma, then the index.
• 10ˣ and eˣ. Wrap the current expression in 10^( ) or exp( ). Useful for fast scientific entries.
• log and ln. log inserts log10; ln inserts the natural log. Both expect a closing parenthesis.
• EE. Adds a lowercase e for scientific notation, so 6.022 then EE then 23 gives 6.022e23.
• ±, mod, !, |x|. Negate, modulo, factorial, and absolute value. Factorial and absolute value act on whatever is in the expression.
• Ans. Inserts the previous result so you can keep stepping through a calculation.
• Const. Opens a searchable list of mathematical, physical, and chemical constants that get inserted as numeric values.

3. Keyboard shortcuts

Digits, +, −, *, /, %, ^, and parentheses come straight from the keyboard. Enter evaluates, Backspace deletes the last character, and Escape clears the expression.