What this scientific calculator handles
This page evaluates a whole typed expression rather than one operation at a time, so you can enter something like sqrt(3^2+4^2) or 2*sin(30)+ln(10) and get a single answer. It covers the functions most people reach for in school maths, physics homework and quick engineering checks: sine, cosine and tangent, natural and base-10 logarithms, square roots, powers, factorials, percentages, sign changes, and the constants π and e. The upper line of the display echoes the expression you evaluated and the large line shows the result; each successful result is also added to the Calculation History card.
How to use it
- Build an expression with the keypad or your keyboard: digits,
+ - * /, brackets,^for powers and.for decimals. - The sin, cos, tan, ln, log and √ keys insert the function name plus an opening bracket. Type the argument and close the bracket with ); functions can be nested, e.g.
sin(ln(5)). - Pick DEG or RAD before evaluating anything with trigonometry. The page always opens in DEG mode.
- Press = or Enter. The rounded result replaces the expression, so you can keep calculating from it.
- n!, % and ± act immediately on whatever is on screen: they evaluate it and replace it with the factorial, the value divided by 100, or the value with its sign flipped.
- Use MS to store the current value, M+ / M- to add or subtract it, MR to recall and MC to clear. Click any history entry to load that result again.
How the calculation works
Before anything is evaluated, the expression is checked against a whitelist: only digits, operators, brackets, the decimal point and the six function names are accepted. The function names are mapped to the browser’s built-in Math.sin, Math.cos, Math.tan, Math.log (natural log), Math.log10 and Math.sqrt; in DEG mode the argument of a trig function is first multiplied by π/180. Normal precedence applies: powers first (right to left, so 2^3^2 is 512), then multiplication and division, then addition and subtraction.
All arithmetic uses 64-bit IEEE 754 floating point, which carries roughly 15–17 significant digits. Non-integer results are rounded to 12 significant digits for display, which hides most binary rounding noise: 0.1+0.2 shows 0.3 and sin(30) shows 0.5. Division by zero displays ∞, and undefined operations such as sqrt(-1) or ln(0-1) show NaN.
Everything runs in your browser. Expressions are never sent to a server. The last 10 history entries are saved in your browser’s localStorage under the key calcHistory so they survive a reload; the memory register is not saved and resets when you close the tab.
Common input mistakes
- Implicit multiplication is not supported. Write
2*sin(30)and2*(3+4);2sin(30)or2(3+4)gives Error. - Negative bases need brackets.
-2^2is ambiguous and is rejected; type(-2)^2for 4 or-(2^2)for −4. This also applies after ± or a negative result, so wrap the number in brackets before using x² or xn. - Wrong angle mode.
sin(90)is 1 in DEG mode but about 0.894 in RAD mode.
Frequently asked questions
Why does sin(180) show a tiny number instead of 0?
The calculator converts 180° to radians using a binary approximation of π, so the sine of that value is about 1.2×10−16 rather than exactly zero. Treat anything that small as zero. For the same reason tan(90) in DEG mode returns a very large number instead of an error.
What is the largest factorial it can compute?
170!, which is about 7.26×10306. 171! exceeds the largest double-precision number, so the n! key only accepts whole numbers from 0 to 170. Fractional factorials (the gamma function) are not available.
Is log base 10 or base e?
log is the common logarithm (base 10) and ln is the natural logarithm (base e). For another base b, divide: log(x)/log(b).
Does the % key do modulo?
No. It divides the current value by 100, so 45 becomes 0.45. To take 15% of 80, enter 80*15, press %, or simply type 80*0.15.
Can other people see my history?
No. History exists only in this browser’s local storage on your device. Clear History deletes it, and clearing your browser’s site data removes it too.