Percentage Calculator
Solve percentage-of, what-percent, increase or decrease, percentage change, percentage difference and reverse percentage problems with the substituted working shown.
Editable live calculator
Change any input — the result updates immediately
No hidden assumptions. Inputs, units and the working stay visible so you can check the calculation.
Calculated result
30
20% of 150 = 30
Show the working
- 1. Convert 20% to decimal: 20 ÷ 100 = 0.2.
- 2. Multiply by the base value: 0.2 × 150 = 30.
More actions
Shared links reopen these inputs. Recent and saved calculations stay in this browser unless you clear site data.
Percentage formulas
- Percentage of = (percentage ÷ 100) × base.
- What percent = (part ÷ whole) × 100.
- Percentage change = ((new − original) ÷ |original|) × 100.
- Percentage difference = |a − b| ÷ ((|a| + |b|) ÷ 2) × 100.
- Reverse percentage = final value ÷ (1 ± percentage ÷ 100).
Limits and assumptions
- What-percent calculations require a non-zero whole value, and percentage-change calculations require a non-zero original value.
- A reverse 100% decrease has a zero multiplier and therefore no finite original value.
- Percentage difference uses the average magnitude of the two values as its denominator.