Pythagoras: the hypotenuse of a 3-4-5 triangle
- Input
- √(3² + 4²)
- Working
- 3² = 9 and 4² = 16. 9 + 16 = 25. √25 = 5.
- Result
- √(3² + 4²) = 5
Scientific Calculator
A full scientific calculator with trig, logarithms, powers, roots and constants — in degrees or radians — with a clear history of what you entered. Runs entirely in your browser — your numbers never leave this device.
Angle
Expression
= 8.5
How it works
Key relations: sin²θ + cos²θ = 1 | tanθ = sinθ / cosθ | log₁₀(10ⁿ) = n | ln(eⁿ) = n | x^(1/2) = √x | n! = n × (n−1) × … × 1
| Angle | sin | cos | tan |
|---|---|---|---|
| 0° | 0 | 1 | 0 |
| 30° | 0.5 | 0.866 | 0.577 |
| 45° | 0.707 | 0.707 | 1 |
| 60° | 0.866 | 0.5 | 1.732 |
| 90° | 1 | 0 | Undefined |
This is a standard scientific keypad: the four arithmetic operations plus parentheses, powers (x^y), square and cube roots, base-10 log and natural log (ln), the trig functions sin, cos and tan with their inverses, factorial (n!), the constants π and e, and a modulo (%) key. Expressions are evaluated with the normal order of operations — parentheses first, then powers and roots, then multiplication and division, then addition and subtraction — so 2 + 3 × 4 gives 14, not 20, unless you add parentheses yourself.
The DEG / RAD toggle decides how trig functions read angles, and it is the single most common cause of 'wrong' answers on any scientific calculator. Use degrees for everyday geometry (sin of 30° = 0.5); use radians for calculus and physics, where angles are naturally measured so that a full turn is 2π. The current mode is always visible next to the display, and inverse trig returns its answer in whichever mode is selected.
Some inputs have no real answer and the calculator says so instead of guessing: the log of zero or a negative number, the square root of a negative number, division by zero, and tan of 90° are all undefined in real arithmetic, and each produces a clear error rather than a misleading number. Very large and very small results switch to scientific notation (for example 1.23e12) so no digits are silently dropped.
Worked examples
Trig in degrees: sin(30°) + cos(60°)
- Input
- Mode = DEG, expression: sin(30) + cos(60)
- Working
- sin(30°) = 0.5 exactly. cos(60°) = 0.5 exactly. 0.5 + 0.5 = 1.
- Result
- sin(30°) + cos(60°) = 1
Roots and powers combined: √144 + 2³
- Input
- Expression: √144 + 2³
- Working
- √144 = 12, because 12 × 12 = 144. 2³ = 2 × 2 × 2 = 8. 12 + 8 = 20.
- Result
- √144 + 2³ = 20
Frequently asked questions
What is the difference between degree and radian mode?
Both measure angles, in different units: a full turn is 360 degrees or 2π radians, so 180° = π radians. Trig functions give completely different values in each mode — sin(30) is 0.5 in degree mode but about −0.988 in radian mode (30 radians). Check the DEG/RAD indicator before blaming the calculator; it is the most common source of unexpected results.
Which functions does this scientific calculator support?
The standard scientific set: addition, subtraction, multiplication and division with parentheses; powers x^y and x²; square root and cube root; base-10 logarithm (log) and natural logarithm (ln); sin, cos, tan and their inverses; factorial n! for whole numbers; the constants π and e; and a modulo (%) key. It does not do symbolic algebra, equation solving, graphing or complex numbers — results are real numbers only.
Why did I get an error for log or square root?
Because the input is outside the function's domain in real numbers. Logarithms are only defined for positive numbers, and square roots of negative numbers are not real (they are imaginary numbers, which this calculator does not handle). Division by zero and tan(90°) are likewise undefined. The error message names the problem instead of displaying a fake result.
What does the answer format 1.23e12 mean?
That is scientific notation: 1.23e12 means 1.23 × 10¹², or 1,230,000,000,000. The calculator switches to this format for very large or very small results so that significant digits are preserved instead of being cut off by the width of the display.
How accurate is this calculator?
It calculates in double-precision floating point — the same arithmetic used by spreadsheets and most programming languages — which is accurate to about 15 significant decimal digits. That is far beyond everyday, school or engineering-estimate needs, though like all floating-point tools it can show tiny rounding artefacts in the last digit of chained calculations.
Does this calculator store or upload my calculations?
No. It runs 100% in your browser: expressions are evaluated on your device, nothing is uploaded to a server, and the on-screen history lives only in this tab. Reload or close the page and the history is cleared.
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