NumberTally Scientific Calculator
A full scientific calculator with a clickable keypad — trig, logarithms, roots, powers, π, and parentheses, with correct order of operations. Type or tap; results update instantly. Now with a history tape, degree/radian toggle, and full keyboard support. Free, no sign-up.
Angles are in degrees.
Result
14
Advanced options
History tape
Keyboard: type digits, + − * / ^ ( ) . and Enter. Backspace deletes. History is stored only in your browser.
Order of operations
The calculator follows standard precedence: parentheses and functions first, then powers (right-associative: 2^3^2 = 2^9 = 512), then multiplication and division, then addition and subtraction. That is why 2+3×4 = 14, not 20 — the multiplication binds tighter.
Degrees vs radians
Trig functions default to degrees (sin 30° = 0.5). Switch to RAD for calculus-style input, where sin(π/2) = 1. The toggle re-evaluates your current expression immediately so you can compare both modes.
Frequently Asked Questions
Why does 2+3×4 equal 14 instead of 20?
Order of operations: multiplication before addition. 3×4 = 12, then 2+12 = 14. Use parentheses to force (2+3)×4 = 20.
Are the sin, cos, and tan functions in degrees or radians?
Your choice — DEG is the default; switch to RAD with the toggle. The label above the display always shows the active mode.
What is the difference between log and ln?
log is base 10, ln is base e (≈ 2.71828). Both need positive inputs.
Why does the calculator show Error?
The expression line above the result names the problem: division by zero, log of a non-positive number, square root of a negative, or unbalanced parentheses.
Is my calculation history private?
Yes — the tape lives in your browser's localStorage and never leaves your device. Clearing it wipes it permanently.