Scientific calculator online: how it works
The scientific calculator evaluates expressions with the functions you would expect on a handheld one: sine, cosine, tangent and their inverses, natural log (ln), base-10 log, square root, powers, factorial and the constants π and e. It uses the same order of operations as the basic calculator, with powers evaluated right to left, so 2^3^2 is 2^9.
The DEG / RAD switch decides how angles are read. In degrees, sin(30) is 0.5; in radians, sin(30) is about −0.988. If a trigonometry answer looks wrong, check the angle mode first. Implicit multiplication such as 2π is understood, and everything is computed in your browser.
Typical uses include checking trigonometry homework, working out slopes and angles for a build, evaluating logarithms and exponential growth, and testing a formula before you put it in a spreadsheet. The expression is shown as you type it, so you can review it before pressing equals.
Formula and assumptions
Formula
Expressions are parsed with standard precedence; ^ is right-associative.
Assumptions
- Trigonometric functions use degrees or radians according to the DEG/RAD switch.
- Precision is standard double-precision floating point (about 15 significant digits).
- log is base 10; ln is natural log.
Worked example
Six quick checks
- sin(30) in degree mode = 0.5.
- 5! = 5 × 4 × 3 × 2 × 1 = 120.
- 2^10 = 1,024.
- sqrt(144) = 12.
- log(1000) = 3 because 10³ = 1,000, and ln(e) = 1.
Result: 0.5, 120, 1,024, 12 and 3.
Limitations
- Precision is standard double-precision floating point (about 15 significant digits). Results are rounded to 12 significant digits for display.
- Factorial only accepts whole numbers from 0 to 170; larger values overflow.
- Functions return an error outside their domain, such as sqrt(−1), ln(0) or asin(2). Complex numbers are not supported.
- Common special angles such as cos(90°) and sin(180°) are cleaned up to exactly 0, but other trigonometric results can carry tiny rounding noise beyond the 12th digit.
