Percentage off vs dollar off: which wins

Quick answer

There is a reliable rule of thumb known as the Rule of 100: for items priced under £100, percentage discounts feel bigger; for items over £100, absolute discounts feel bigger. A 25 percent discount on a £40 product reads as more than a £10 discount on the same product. A £50 discount on a £200 product reads as more than 25 percent off the same product. Pick the framing that makes the discount sound largest.

The psychology

The Rule of 100 is rooted in numerosity bias — the human brain treats bigger numbers as more impressive regardless of the units involved. 25 is bigger than 10, so '25 percent off' feels bigger than '£10 off' even when the savings are identical. Above £100, the absolute number flips — £50 is bigger than 25, so '£50 off' wins.

This bias is so strong that it overrides actual mathematical comparison even when both numbers are visible. Marketers exploit it constantly: cheap items get percentage labels, expensive items get pound labels. The buyer never feels manipulated because the framing isn't dishonest — the savings are real either way. It's purely a presentation choice.

Example offer copy

For a £29 candle (percentage wins): Headline: 30% Off Our Bestselling Soy Candles Primary text: Our hand-poured candles are 30% off this weekend. Lavender, sandalwood, and the new fig & cedar scent all included. Free shipping on orders over £40.

For a £349 mattress topper (dollar wins):
Headline: £100 Off The Memory Foam Topper That Saved My Back
Primary text: £100 off our medium-firm topper this weekend. Reviewers call it 'a new mattress without the price tag.' Free returns within 100 nights.

Why it works

Both ads describe the same proportion — about 30 percent off. The candle ad uses percentages because '30' is a bigger, punchier number than '£8.70.' The mattress ad uses pounds because '£100' is a bigger, punchier number than '28.6%.' The Rule of 100 isn't a guess; it's been tested across thousands of campaigns and the lift is consistent enough to bank on. When in doubt, pick the framing where the number itself is largest.

FAQs

Does the Rule of 100 apply to subscriptions?

Yes, but use the monthly price as the reference. A £29/month subscription should use percentage discounts; a £150/month subscription should use absolute pound discounts.

What about really small items?

Below £10, percentages still win but margins are tiny. Often 'half off' (a phrase, not a number) outperforms both '50% off' and '£3 off' for impulse-priced items.

Can I use both at once?

Yes — 'Save £100 (30% off)' lets the buyer pick whichever number feels bigger. This is common above £100 where you want to communicate both the absolute amount and the percentage feels meaningful.

Does this work for B2B?

Less so. B2B buyers calculate. Show the absolute saving and the percentage; don't rely on framing tricks.

What's the threshold currency-adjusted?

Roughly £100, $100, or €100. The brain's threshold isn't tied to a specific currency — it's about whether the percentage number is bigger than the absolute number.

Stop guessing which offer will convert

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