Percentage Calculator
Last updated: 2026-06-25
X% of A is A × (X ÷ 100), the part/whole ratio is part ÷ whole × 100(%), and the percentage change is (new − old) ÷ old × 100(%).
Pick a mode below and enter two values to instantly see the result and the formula.
Percentage calculation
Result
0
Decimal results are rounded to 6 decimal places. Large numbers are grouped with thousands separators (,).
How to use
- Choose a mode — Select X% of A, part/whole ratio, percentage change, markup or discount.
- Enter values — Enter the two numbers (A, X) required by the selected mode.
- View the result — Press Calculate to see the result along with the formula used.
How to calculate percentages: formulas
A percentage (%) is a ratio out of 100, so B% of a value equals that value multiplied by B/100. The percentage calculations people use most often fall into three main types.
| Mode | Formula | Example |
|---|---|---|
| X% of A | A × (X ÷ 100) | 10% of 50,000 = 5,000 |
| Part/whole ratio | A ÷ B × 100 (%) | 30 is 25% of 120 |
| Percentage change | (B − A) ÷ A × 100 (%) | 100→120 is +20% |
| Add X% | A × (1 + X ÷ 100) | 10,000 + 10% = 11,000 |
| Subtract X% (discount) | A × (1 − X ÷ 100) | 10,000 − 10% = 9,000 |
When computing percentage change, remember that the base (old value) is the denominator. The same absolute difference yields a larger percentage change when the base is smaller. Also, when a value is already in percent (interest rate, unemployment rate), changes are best expressed in percentage points (pp). For more, see the complete guide to percentages.
Frequently Asked Questions (FAQ)
How do I calculate X% of a number?
X% of a number A equals A × (X ÷ 100). For example, 10% of 50,000 is 50,000 × 0.1 = 5,000.
How do I find the percentage change (increase or decrease)?
Percentage change is (new value − old value) ÷ old value × 100(%). A positive result is an increase, a negative result is a decrease. For example, going from 100 to 120 is (120−100)/100×100 = +20%.
What is the difference between percent (%) and percentage points (pp)?
A percentage point is the arithmetic difference between two percentage values. If a rate rises from 3% to 5% that is a 2 pp increase, but as a percentage change it is (5−3)/3×100 ≈ 66.7%.
How do I calculate a discounted price?
If the discount rate is X%, the discounted price is original × (1 − X ÷ 100). Use the "Subtract X% from A" mode to get the after-discount price directly.
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Last updated: 2026-06-25