Percentage Calculator

Percent vs percentage points

A percentage compares a part with a whole; a percentage point is the plain difference between two percentages. If a tax rate goes from 5% to 6%, it rose by 1 percentage point but by 20 percent (1 ÷ 5). Mixing the two up is the most common mistake in news and reports, so this page is explicit about which one it shows: the change calculator returns a percent change relative to the starting value, never points.

Everyday uses

• Discounts and tax: 15% of NT$2,500 is NT$375, so the price after a 15% discount is NT$2,125.
• Growth and decline: sales rising from 32,000 to 36,000 is a 12.5% increase, but falling back from 36,000 to 32,000 is only an 11.1% decrease, because the base changed.
• Achievement rate (達成率): 350 against a target of 2,000 is 17.5%.
• Grades, interest rates, battery levels, Taiwan's 5% business tax and tips all use the same four formulas.

The formulas

• X% of Y = Y × X ÷ 100
• X as a percent of Y = X ÷ Y × 100
• Percent change from A to B = (B − A) ÷ |A| × 100
• Y increased by X% = Y × (1 + X ÷ 100); decreased = Y × (1 − X ÷ 100)

Privacy

Everything is calculated on your device. Nothing you type is sent anywhere or stored.