Percentage Calculator: Frequently Asked Questions

Result = (Percentage ÷ 100) × Number. For example, 15% of 200 = (15 ÷ 100) × 200 = 30.

Percentage change = ((New Value − Old Value) ÷ Old Value) × 100. A positive result is an increase, a negative result is a decrease.

A percentage expresses a ratio as a fraction of 100. A percentage point is the arithmetic difference between two percentages. If a rate rises from 5% to 7%, it has risen by 2 percentage points, but by 40% in relative percentage terms.

Divide the part by the whole and multiply by 100. If 35 people out of 140 responded, the response rate is (35 ÷ 140) × 100 = 25%.

For reverse percentages (finding the original price before a percentage increase or decrease), use Type 2: enter the known value as the part and solve. For example, if a price after 20% discount is £80, the original price is £80 ÷ 0.8 = £100.

Because each percentage applies to a different base. 100 + 50% = 150. Then 150 − 50% = 75. The second percentage applies to the larger number, so the decrease is proportionally larger in absolute terms.

Use Type 1. Enter the tip percentage (e.g. 18) and the bill amount. The result is the tip in dollars. Add it to the bill for the total. Or use the Tip & Bill Splitter to split the result among multiple people.