Percentage off or pounds off? The short answer: £ off usually wins on smaller baskets and % off wins on bigger ones, and the switch happens at a break-even basket you can work out in one step. Enter both offers above and the calculator does it for you. Below is how it works, so you can check any deal in your head.
The break-even rule
Divide the pounds-off amount by the percentage written as a decimal. The result is the basket value where both vouchers save exactly the same.
£10 ÷ 0.15 = £66.67. Below £66.67, £10 off saves more. Above it, 15% off saves more.
Check it with three baskets
- £50 basket: 15% is £7.50, so £10 off wins by £2.50.
- £66.67 basket: both save £10.
- £100 basket: 15% is £15, so the percentage wins by £5.
Break-even baskets for common pairs
| % off | £ off | Break-even basket | Better below it | Better above it |
|---|---|---|---|---|
| 10% | £5 | £50 | £5 off | 10% off |
| 10% | £10 | £100 | £10 off | 10% off |
| 15% | £10 | £66.67 | £10 off | 15% off |
| 20% | £15 | £75 | £15 off | 20% off |
| 20% | £20 | £100 | £20 off | 20% off |
| 25% | £15 | £60 | £15 off | 25% off |
| 30% | £25 | £83.33 | £25 off | 30% off |
Turn £ off into a percentage
A quick way to compare is to convert the fixed saving into the percentage it works out to: £ off ÷ basket.
- £10 off a £50 basket is 20% off.
- £10 off a £100 basket is 10% off.
- £10 off a £200 basket is 5% off.
The same £10 gets weaker as the basket grows, while a percentage code keeps scaling. That is the whole reason the break-even exists.
When the headline numbers mislead
Minimum spend
Say you have 15% off with no minimum, or £10 off when you spend £50, and your basket is £45. The £10 code will not apply. Adding £5 of extras to unlock it costs you £50 − £10 = £40 in total, against £45 − £6.75 = £38.25 with the 15% code. Only top up if you genuinely want the extra items.
Maximum discount caps
Some percentage codes stop saving after a set amount. Take 25% off capped at £20 against £15 off. The cap bites at £80 (25% of £80 is £20). On a £200 basket, 25% would be £50, but you only get £20, so you pay £180 against £185 with the £15 code. The percentage still wins, just by far less than it first appears. Always enter the capped saving, not the headline figure.
Sale items and exclusions
Many codes exclude sale lines, certain brands or categories. A 20% code on a £60 sale-price item saves £12, but if the item is excluded it saves nothing. Work out the saving only on the items the code covers. If a code does stack with a reduction, the Stacked Discount Calculator shows the real combined saving.
Delivery charges
A free delivery code is worth whatever fee you would otherwise pay. As an example, if delivery costs £3.99, free delivery beats 10% off a £30 basket (£3). If the fee is lower or the basket larger, the percentage may win. The Free Delivery Calculator helps with the threshold side of this.
One basket or several items?
A £ off voucher is taken once per order, so it favours a single pricier purchase. A percentage code scales with everything it covers, so it favours a big, mixed basket.
A quick method for any two vouchers
- Check each code's terms: minimum spend, cap, exclusions and expiry.
- Work out the saving each code gives on your actual eligible basket.
- Subtract any delivery fee that applies to one route but not the other.
- Pick the lower final total, not the bigger-looking number.
Once you have chosen, use the Discount Calculator to confirm your final price. If you are shopping around for codes to compare, you can browse stores on PrimeVoucher. Cashback is a separate saving that sits on top, so see the Cashback Calculator if your retailer offers it.