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Percentage Calculator

Use one page to calculate percent of a value, find percentage share, and measure growth or decline.

Percent (%)Base value

Result

Supporting values

204

How this calculator works

This tool focuses on the three percentage flows people use most often: taking a share of a number, measuring a portion of a whole, and calculating percent change.

Core formulas

A% of B = A / 100 × B
A is what % of B = A / B × 100
Percent change = (new - old) / old × 100

Frequently Asked Questions

Can percent change be negative? expand_more

Yes. If the new value is lower than the previous value, the result becomes a negative percentage.

What happens if the base value is zero? expand_more

When the denominator becomes zero, the tool returns 0 to avoid an invalid result.

Can I use this for discounts and tax? expand_more

Yes. The A% of B mode works well for discounts, tax amounts, tips, and commissions.