Quick guide
Free Online Calculator with Percentages and Scientific Functions
Handle everyday arithmetic, percentages, parentheses, powers, roots, logarithms and trigonometry on one page. Use the keypad or keyboard, switch between DEG and RAD, and reuse your history. A three-mode percentage helper solves common questions without building a formula. Everything runs in your browser; values and expressions are not sent to the VPS.
What this tool does
- Follows operator precedence and supports parentheses, percentages, powers and factorials.
- Calculate a percentage of a value, what percentage one value is of another, and percentage increase or decrease.
- Includes sin, cos, tan, inverse functions, log, ln, square root, π and e.
- Includes memory, reusable history and copy controls while keeping calculation data in your browser.
How to use Online Calculator
- 1Choose the percentage helper or enter a formula with the keypad.
- 2Enter both values for a percentage question, or choose DEG/RAD before using trigonometry.
- 3Calculate, check the formula and result, then copy it or select a history entry to reuse it.
Frequently asked questions
How do I find 15% of 1,200?
Choose Percentage of a value and enter 15 and 1,200 to get 180. You can also enter 1,200 × 15% as an expression.
How do I find what percentage one value is of another?
Choose What percentage, then enter the part and total. For example, 180 out of 1,200 is 15%, using 180 ÷ 1,200 × 100.
How do I calculate a percentage increase or decrease?
Choose Percentage change and enter the original and new values. From 1,200 to 1,380 is a 15% increase, using (1,380 − 1,200) ÷ 1,200 × 100.
How does the percent (%) key work?
The calculator treats 15% as 15 ÷ 100, or 0.15. Therefore, 1,200 × 15% equals 180. To increase 1,200 by 15%, enter 1,200 × (1 + 15%), which equals 1,380.
Does the calculator follow the order of operations?
Yes. It evaluates parentheses and powers first, then multiplication or division, followed by addition or subtraction. For example, 2 + 3 × 4 equals 14.
What is the difference between DEG and RAD?
DEG interprets angles in degrees, so sin(30) equals 0.5. RAD uses radians, so sin(π ÷ 2) equals 1.
Why do some expressions show an error?
The calculator blocks undefined or unsupported results, including division by zero, tan(90°), square roots of negative numbers, and factorials outside the integers from 0 to 170.
Are my expressions and history sent to the VPS?
No. Calculations run in your browser, and the current values and expression are not transmitted. History and memory are stored in this device's localStorage and can be cleared at any time.