Scientific Calculator — Free, Online, With History
Type or tap: trig, logs, powers, roots, factorials and constants, with proper operator precedence.
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History click a line to reuse it
A scientific calculator that works the way you write maths: type 2sin(30) + sqrt(16) or tap the keys, and the result updates as you go. It follows the real precedence rules — 2^3^2 is 512, -2^2 is −4, 2(3+4) multiplies — and switches between degrees and radians with one tap.
Every calculation is kept in a history you can click to reuse, and ans always holds the last result.
How to use Scientific Calculator
- Type the expression in the display, or tap the keys. Functions take parentheses:
sin(30),log(100). - Watch the live result under the expression; press = or Enter to commit it to the history.
- Choose DEG or RAD for trigonometry — DEG is the default because that's what most people mean.
- Chain calculations with
ans, or start typing an operator and it continues from the last answer.
Precedence — what gets calculated first
From tightest to loosest: postfix ! and %, then ^ (right-to-left, so 2^3^2 = 2^9), then unary minus, then × ÷ mod, then + −. The unary-minus placement is the one that trips people up: -2^2 is −4 here, as in every maths textbook, Excel-style calculators and Python. If you mean (−2)², write the parentheses.
What the keys mean
- ln is the natural log (base e); log is base 10.
log2(x)is also accepted when typed. - % is "percent":
50%is 0.5, so200 × 15%is 30. Use mod for the remainder:17 mod 5 = 2. - n! is the factorial of a non-negative integer, up to 170! (beyond that the result overflows).
- π and e can be typed as
piande;2piand3emultiply implicitly. - sin⁻¹ etc. are the inverse functions (
asin,acos,atan), returning degrees or radians to match the mode.
Degrees or radians?
Degrees for geometry, navigation, and anything a person measured with a protractor; radians for calculus, physics and programming (every language's Math.sin takes radians). The classic mistake is computing sin(90) in radian mode and getting 0.894 — if a trig result looks nonsensical, check the mode first.
Floating point, honestly
Computers store decimals in binary, so 0.1 + 0.2 is internally 0.30000000000000004. This calculator rounds results to 12 significant digits for display, which hides that noise while keeping engineering-grade precision. It also refuses rather than guesses: division by zero, sqrt(-1) and asin(2) report an error instead of NaN.
For percentage-specific arithmetic (what percent of, percent change), the percentage calculator lays the cases out; for unit-aware maths, the unit converter.
Frequently asked questions
Why does -2^2 give -4?
Because exponentiation binds tighter than the minus sign, in maths notation and in nearly every calculator and programming language. −2² means −(2²) = −4. If you want (−2)² = 4, type the parentheses.
sin(90) gives 0.894 — what's wrong?
You're in radian mode: sin of 90 radians is 0.894. Switch to DEG for degrees, where sin(90) = 1. This is the single most common scientific-calculator mistake, which is why the mode toggle sits right above the keys.
Can I type expressions instead of tapping?
Yes — the display is a text field. Type 2*pi*5, sqrt(2)/2, 5!, 17 mod 5, log(1000); ×, ÷ and ** are accepted too. Enter or = commits to the history.
What does % do?
It divides by 100, so 15% is 0.15 and 80 × 15% is 12. It is not a remainder operator — use mod for that: 17 mod 5 = 2.
How precise are the results?
Calculations use double-precision floating point (about 16 significant digits) and display 12, which removes binary rounding noise like 0.30000000000000004. Results are exact enough for engineering and science coursework; they are not arbitrary-precision.