Percentage calculator
Work out 15 % of 80, what percent 20 is of 80, the change from 80 to 100 (+25 %), or the base when 12 is 15 %.
- Runs in your browser
- No upload
- Instant result
Assumptions & formula
Formula and assumptions
A × B/100; A/B × 100; (B−A)/abs(A) × 100; A × 100/B
Results
Enter values and press Calculate to see the result here.
How to use this calculator
- Set inputs and units
Choose percentage value, share, change or reverse. a and b mean different quantities in each mode.
- Calculate
Check this worked example: value: a=250, b=20 → 50; change: a=100, b=120 → 20%
- Results
Tell an amount apart from a percentage. Change divides by the absolute starting value.
Questions and limits
Are successive increases additive?
No. Two 20% increases multiply by 1.2 twice, which gives 44%, not 40%.
Which input errors should I correct?
A zero baseline can't define a percentage change. Check the denominator and the field labels for the mode you chose.
What does this calculation leave out?
Arithmetic only. It covers no tax, no compounding interest schedule and no interpretation of percentage points.