Free Maths Calculator

Reverse Percentage Calculator

When you know the amount after a percentage increase or decrease, this calculator works backwards to the original using the unitary method: find what 1% is worth, then scale up to 100%. It is built for the reverse percentage questions that appear in every GCSE paper and catch almost everyone out.

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    Worked Example

    After a 20% price increase, a train ticket costs £360. What did it cost before the increase?

    1. After a 20% increase the ticket is 100% + 20% = 120% of the original price
    2. 120% = £360, so 1% = 360 ÷ 120 = £3
    3. The original price is 100%:3 × 100 = £300

    Answer: £300

    Try These Yourself

    After a 25% increase, a phone costs £250. What was the original price?Show answerHide answer

    Answer: £200

    125% = £250, so 1% = £2, and 100% = £200.

    A coat costs £54 after a 10% discount. What was the full price?Show answerHide answer

    Answer: £60

    90% = £54, so 1% = £0.60, and 100% = £60.