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Percentage of a Percentage Calculator

Calculate a percentage of another percentage — find the result, work backwards to find the base, or find what percentage one value is of another.

What is % of %?
% of what percentage is %?
What percentage of % is %?

What Is a Percentage of a Percentage?

A percentage of a percentage means applying one rate to another rate as its base value. The result is also a percentage.

Formula: A% of B% = (A ÷ 100) × B

Example: 25% of 80% = (25 ÷ 100) × 80 = 20%

This is different from a standard percentage calculation where the base is a plain number. Here, both inputs are rates.

How to Use This Calculator

Block 1 — Find the result: Enter both percentages to find what A% of B% equals.

Block 2 — Find the base: If you know the percentage applied (A%) and the result (R%), the calculator finds what base percentage was used.

Block 3 — Find what percentage: If you know the base (B%) and the result (R%), the calculator tells you what percentage was applied.

Common Use Cases

Stacked Discounts

When a shop applies a second discount on top of an already-discounted price, the second discount applies to the reduced percentage — not the original full price.

Example: 30% off an item that is already 60% of the original price. 30% of 60% = 18% — the second discount removes 18 percentage points from the original, not 30.

Effective Tax or Commission Rates

If a tax rate applies only to a portion of income or a sub-total, the effective rate on the full amount is a percentage of a percentage.

Example: A 15% tax on 40% of total revenue equals an effective rate of 6% on total revenue.

Probability

In probability, the chance of two independent events both occurring is calculated by multiplying their probabilities — which is equivalent to finding a percentage of a percentage.

Example: A 70% chance of rain and a 50% chance of it raining during your specific time window: 50% of 70% = 35% chance.

Frequently Asked Questions

What does 'percentage of a percentage' mean?

It means applying one percentage to another percentage as its base value. For example, 50% of 80% means you take half of 80%, which is 40%. The formula is: (A ÷ 100) × B = result.

What is 30% of 20%?

30% of 20% is 6%. The calculation is (30 ÷ 100) × 20 = 6.

Why do stacked discounts not simply add up?

Because each discount applies to the already-reduced price, not the original. A 20% discount followed by a 10% discount is not the same as 30% off. The second discount applies to 80% of the original price, so the effective reduction is 28%, not 30%.

How is this different from a regular percentage calculation?

A regular percentage finds a percentage of a plain number — for example, 20% of 150. A percentage of a percentage finds a percentage of another percentage value — both inputs are percentages. The result is also a percentage.

Can the result be more than 100%?

Yes. For example, 200% of 80% equals 160%. This can represent scenarios like a doubled rate applied to an existing percentage.

What is the formula for percentage of a percentage?

Result = (A ÷ 100) × B, where A and B are both percentages and the result is also a percentage. Equivalently, Result = A × B ÷ 100.

How do I find the base percentage if I know the result?

Use the second block of this calculator. If you know A% of some percentage equals R%, enter A and R — the calculator finds the base percentage using: Base = R × 100 ÷ A.