Crunch Percentage Calculator
Six percentage tools in one: percent of a number, a number as a percent of another, increase, decrease, percent change and percent difference — results update as you type.
How it works
Every mode uses the same core idea — a percent is a fraction of 100. Percent of: (p ÷ 100) × number. Number as a percent: (part ÷ whole) × 100. Percent change: (new − old) ÷ old × 100. Percent difference is the one people mix up with change: it compares two numbers symmetrically, dividing by their average — |a − b| ÷ ((a + b) ÷ 2) × 100 — so it gives the same answer whichever order you enter the numbers.
Frequently asked questions
What is the difference between percent change and percent difference?
Percent change is directional: it measures growth or decline from an old value to a new one, so swapping the numbers changes the answer. Percent difference treats both numbers equally by dividing by their average, so the order does not matter.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 30 out of 150 is 30 ÷ 150 × 100 = 20%. Use the "Number as %" mode above.
How do I increase a number by a percentage?
Multiply the number by (1 + p ÷ 100). Increasing 150 by 20% gives 150 × 1.2 = 180. The "% increase" mode shows both the new value and the amount added.
Can a percentage be more than 100?
Yes. A percent is just a ratio to 100 — 250% of 40 is 100, and a price that triples has increased by 200%. Percentages below 0 appear when a change is negative.
🏷️ Shopping math, handled
Pair percentages with the Discount Calculator to see the final price with tax included.