Basic Calculator
A free online calculator for everyday arithmetic — type any expression with +, −, ×, ÷, powers, roots and parentheses and get the answer instantly.
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What this tool does
A free online calculator for everyday arithmetic — type any expression with +, −, ×, ÷, powers, roots and parentheses and get the answer instantly. Results use double-precision arithmetic, exact for whole numbers up to 2^53. Division by zero and other undefined operations show an error instead of a misleading number.
How to use the Basic Calculator
- Enter or select expression (e.g. 123+877, (8+4)/3, 2^10, √144).
- Read the calculated result; change any measurement to compare alternatives.
Formula
Standard order of operations: parentheses first, then powers and roots, then × and ÷ left to right, then + and −. A built-in safe parser evaluates the expression — no code is ever executed.
- expression
- Expression (e.g. 123+877, (8+4)/3, 2^10, √144)
Results use double-precision arithmetic, exact for whole numbers up to 2^53. Division by zero and other undefined operations show an error instead of a misleading number.
Worked example
For basic calculator, the following measurements illustrate the exact method: Expression (e.g. 123+877, (8+4)/3, 2^10, √144): 123+877.
Inputs
- Expression (e.g. 123+877, (8+4)/3, 2^10, √144)123+877
Result
- Result1,000
- Expression123+877
Results explained
- Result
- Result from the formula above. Results use double-precision arithmetic, exact for whole numbers up to 2^53. Division by zero and other undefined operations show an error instead of a misleading number.
- Expression
- Expression from the formula above. Results use double-precision arithmetic, exact for whole numbers up to 2^53. Division by zero and other undefined operations show an error instead of a misleading number.
Frequently asked questions
Type any arithmetic expression — for example 123+877, (8+4)/3 or 15% of a number written as 200*0.15 — and the result appears instantly. Parentheses, powers (^), square roots (√ or sqrt) and factorials (5!) are all supported.
The calculator follows PEMDAS/BODMAS: parentheses first, then exponents and roots, then multiplication and division from left to right, then addition and subtraction from left to right. That is why 2+3*4 equals 14, not 20.
Multiply the number by the percentage as a decimal: 17% of 250 is 250*0.17 = 42.5. To add 17% to a price, multiply by 1.17; to take 17% off, multiply by 0.83.
Dividing by zero has no real-number answer — there is no number that multiplied by 0 gives back the dividend — so the calculator shows an error rather than inventing a value.
Whole-number results are exact up to 2^53 (about 9 quadrillion). Decimal results use standard double precision, the same as a physical calculator app, so the last displayed digit may be rounded.
No. The expression is parsed and evaluated entirely in your browser by a safe hand-written parser; nothing is uploaded or stored.