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Percentage Guru

Original price after 70% off

Enter what you paid and this page works back to the pre-sale price. The discount is fixed at 70% — the price is yours to change.

e.g. £21.00 after 70% off → £70.00 original

final ÷ (1 − rate ÷ 100) = original

Worked example at 70% off

You paid £21.00 in a 70% off sale.

  1. 100% − 70% = 30% of the original price remains
  2. As a decimal that is 0.30000000000000004
  3. 21 ÷ 0.30000000000000004 = £70.00
  4. You saved £49.00

Check it forwards: £70.00 − 70% = £21.00 ✓

Adding 70% back to £21.00 would give £35.70 — which is wrong, and wrong by more as the percentage grows. The discount was taken off the larger original, so putting it back on the smaller sale price never reaches it.

Where 70% off shows up

Seventy percent off is the deep end of a normal clearance cycle. Retailers use it to close out a season entirely, and it is frequently the final advertised depth before stock moves to an outlet or is liquidated.

At this depth the reversed original can look startling: you paid 30%, so the original was more than triple. That is worth checking rather than assuming — a very large implied original is the pattern that makes a reference price worth questioning.

70% off price table

What twenty common sale prices were before the 70% reduction. Every figure is divided by 0.30000000000000004.

Sale prices and the original price each implies at 70% off
You paidOriginal priceYou saved
£5.00£16.67£11.67
£9.00£30.00£21.00
£13.00£43.33£30.33
£17.00£56.67£39.67
£21.00£70.00£49.00
£25.00£83.33£58.33
£29.00£96.67£67.67
£33.00£110.00£77.00
£37.00£123.33£86.33
£41.00£136.67£95.67
£45.00£150.00£105.00
£49.00£163.33£114.33
£53.00£176.67£123.67
£57.00£190.00£133.00
£61.00£203.33£142.33
£65.00£216.67£151.67
£69.00£230.00£161.00
£73.00£243.33£170.33
£77.00£256.67£179.67
£81.00£270.00£189.00

Doing it without a calculator

Multiply by ten, then divide by three. You paid 30%, so the original is 10/3 of the sale price — about 3.33 times. On £21 that is 210 ÷ 3 = £70. The large multiplier is why small differences in the sale price swing the implied original so much.

The exact method is always the same: divide by 0.30000000000000004. 70% off leaves 30% of the original, so dividing by 0.30000000000000004 undoes it precisely. Multiplying, or adding the percentage back on, gives a number that is always too small — and the error grows with the discount.

Frequently asked questions

Is a 70% discount usually genuine?

It can be, at genuine end-of-season clearance. The figure worth checking is the implied original: reverse it, then compare against what the same item costs elsewhere rather than against the ticket.