Percentage Calculator
To find x% of a number, multiply by x ÷ 100; 15% of 240 = 0.15 × 240 = 36. Type 15% × 240 in the calculator below.
At a glance
| What it is | Free percentage calculator: find a percent of a number, discounts, tips and percentage change. 15% of 240 = 36. Big keys, works on phones. |
|---|---|
| Type | Interactive guide with a calculator |
| Level | High school and college |
| Price | Free, with no account or sign-up |
| Works offline | Yes, after the first visit; installs as an app |
| Made by | Aalok (aalok.builds@gmail.com) |
| Last updated | 1 November 2026 |
Key facts
| x% of y | x ÷ 100 × y |
|---|---|
| Discount | price − price × discount% |
| Percentage change | (new − old) ÷ old × 100 |
| What percent is a of b? | a ÷ b × 100 |
| Examples | 15% of 240 = 36; 25% off 800 = 600 |
How do you find a percentage increase or decrease?
If a price rises from 80 to 100, the change is (100 − 80) ÷ 80 × 100 = 25%. If it falls from 100 to 80, the change is −20%, because the starting value is different.
How to use it in Plotline
- 15% × 240 is already entered; its answer shows next to the input.
- Use the % key: 20% × 80 = 16.
- For a discount, type the price minus the percentage of it: 800 − 800 × 25% = 600.
Frequently asked questions
How do I calculate a tip?
Multiply the bill by the tip percentage: a 15% tip on 60 is 15% × 60 = 9, making the total 69. For a quick 20% tip, divide the bill by 5 instead.
Is it free?
Yes. The calculator is free with no account and no sign-up, and there are no ads inside it. It installs as an app on a phone or computer and keeps working without an internet connection after your first visit.
Learn more
Related
- Factorial calculator – Free factorial calculator: n! = n × (n − 1) × … × 1.
- Square root calculator – Free square root calculator, plus cube roots and nth roots.
- Log calculator – Free log calculator: find log base 10, natural log ln, log base 2 or any base.
Free calculators
- Graphing Calculator – Graph functions, circles, inequalities, polar and parametric equations instantly.
- Scientific Calculator – Free online scientific calculator with sin, cos, tan, inverse trig, logs, powers, roots, factorials, degrees and radians.
- Basic Calculator – A simple, free online calculator for add, subtract, multiply, divide, percent, square and square root.
- Matrix Calculator – Free matrix calculator: determinant, inverse, multiplication, transpose, RREF, rank, trace and powers, with exact fractions.
Plotline is an independent project and is not affiliated with Desmos, Texas Instruments or Casio.