Percentage Calculator
Three percentage modes in one tool: find X% of Y, work out what percentage X is of Y, or measure the change between two values.
25% of 200
50
Result
As a fraction
25/100
Remaining
150
- Percentage
- 25%
- Number
- 200
- Result
- 50
How this was calculated
- 1.Convert the percentage to a decimal: 25% = 0.25.
- 2.Multiply: 0.25 × 200 = 50.
How the percentage calculation works
A percentage is simply a fraction with 100 on the bottom. So 25% means 25/100, or 0.25, and "25% of 200" is 0.25 × 200 = 50. Every percentage question reduces to this one idea.
Percentages are always relative to something. A 20% rise followed by a 20% fall does not return you to the start — 100 → 120 → 96 — because the second percentage is taken from a different base. That is the most common percentage trap.
Percentage change divides the difference by the original value. Going from 50 to 75 is a 50% increase; going from 75 back to 50 is a 33.3% decrease.
Worked example
What is 15% of 240, and what percentage change is 240 → 300?
- →15 ÷ 100 = 0.15
- →0.15 × 240 = 36
- →Change: (300 − 240) ÷ 240 = 0.25
Answer: 15% of 240 is 36, and 240 → 300 is a 25% increase.
Percentage FAQs
How do I add a percentage to a number?
Multiply by 1 plus the rate. Adding 8% to 250 is 250 × 1.08 = 270. Choose the increase mode above to see it worked through.
How do I remove a percentage?
Divide by 1 plus the rate, or multiply by 1 minus the rate. Removing 20% VAT from 120 is 120 ÷ 1.2 = 100, not 120 − 24 = 96.
Why is a 50% fall not undone by a 50% rise?
Because each percentage applies to a different base. 100 falls to 50, then 50 rises by 50% to 75 — a net loss of 25%.
Percentage Calculator is part of the math calculators collection on Calcora, alongside 7 other tools. Results are calculated in your browser and are for information only — see our disclaimer.
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