Percentage Calculator
Four calculators in one: find what X% of Y is, reverse lookup, track percentage change, and add or subtract a percentage from any number.
How to Use the Percentage Calculator
ToolsPix Percentage Calculator covers every common percentage problem with four dedicated calculators. Pick the one that matches your question, enter your numbers, and the result — including the full formula — appears instantly.
Choose the right calculator
- Calculator 1 — X% of Y: Enter a percentage and a base number to find the portion. Example: 15% of 200 = 30.
- Calculator 2 — Reverse lookup: Enter X and Y to find what percent X is of Y. Example: 30 is 15% of 200.
- Calculator 3 — Percentage change: Enter a start value and an end value to see the percentage increase or decrease between them.
- Calculator 4 — Add or subtract: Apply a percentage markup or discount directly to a number using the dropdown switch.
Common percentage formulas
- X% of Y:
(X ÷ 100) × Y - X is what % of Y:
(X ÷ Y) × 100 - Percentage change:
((New − Old) ÷ |Old|) × 100 - Add X% to N:
N + (N × X ÷ 100)
FAQ
How do I calculate what X% of a number is?
To find X% of Y, multiply Y by X and divide by 100: Result = (X ÷ 100) × Y. For example, 15% of 200 = (15 ÷ 100) × 200 = 30. Use Calculator 1 — enter the percentage and the number and the result appears instantly.
How is percentage change calculated?
Percentage change = ((New Value − Old Value) ÷ |Old Value|) × 100. A positive result is an increase; a negative result is a decrease. For example, changing from 80 to 100 gives ((100 − 80) ÷ 80) × 100 = +25%.
What is the difference between percentage increase and percentage decrease?
Both use the same formula. Percentage increase means the new value is larger than the original (positive result). Percentage decrease means the new value is smaller (negative result). Calculator 3 automatically shows an increase or decrease badge next to the result.
How do I add or subtract a percentage from a number?
To add X% to a number N, calculate N + (N × X ÷ 100). To subtract X%, calculate N − (N × X ÷ 100). For example, adding 20% to 250 gives 250 + (250 × 0.20) = 300. Calculator 4 handles both operations with a dropdown switch.
Is the percentage calculator free and private?
Yes, it is completely free. All four calculators run entirely in your browser — no data is sent to any server, nothing is stored between sessions, and no account or sign-up is required.