The Rule of 100
Frame discounts as the bigger number by switching between percentages and absolutes at £100
- Difficulty
- Easy
- Time to result
- ~days to results
- Steps
- 4
- Confidence
- 86%
The Rule of 100, coined by Jonah Berger from Gonzalez's research, exploits the fact that people respond naively to numbers — reacting to a number's size rather than its true value. For a cheap product, a percentage discount usually produces a larger-sounding number than the absolute saving; for an expensive product, the reverse is true. The cut-off sits around 100 (pounds, dollars or euros). Below it, quote the percentage (25% beats a 12-peso saving on a 48-peso item); above it, quote the absolute (a 120-peso saving beats 25% on a 480-peso item). A related move is reframing a price cut as added value — Rao's pharmacy study found '50% more' hand lotion sold 81% better than an identical '35% off', because 'more' is always the bigger absolute number.
Origin
Jonah Berger distilled Rule of 100 from behavioural pricing research, notably Gonzalez's balloon and jacket studies and Rao's 2012 hand-lotion experiment. Richard Shotton popularised it in The Illusion of Choice.
Core principles
- 01People react to the size of a number, not what it represents
- 02Snap purchase decisions are made on speed, not maths
- 03The same discount can feel bigger or smaller depending on how it is expressed
- 04Honesty is required: only quote the genuinely larger framing
How to run it
- 1
Check the price
Determine whether the item sells for more or less than 100 units of your currency.
Pro tip Set the threshold once per market so the whole team applies it consistently.
- 2
Pick the bigger framing
Under 100, lead with the percentage. Over 100, lead with the absolute pound/dollar saving.
Watch out Never inflate or misrepresent — only choose the genuinely larger honest expression.
- 3
Test a bonus frame
Where relevant, express the offer as extra product ('50% more') rather than a discount, since value-added numbers are usually larger.
- 4
Validate with a live test
Run the alternative framings against each other on real traffic before committing.
In the wild
A pharmacy sold the same hand lotion for 16 weeks, alternating the message between '35% discount' and '50% more' product. Mathematically identical offers, but on the '50% more' weeks the store saw 81% more sales because shoppers reacted to the larger number rather than its actual value.
→ 81% uplift in sales from reframing a discount as added volume.
Gonzalez offered a 48-peso pack of balloons at either a 12-peso or a 25% discount; shoppers preferred the 25%. She then offered a 480-peso jacket at a 120-peso or 25% discount; now shoppers rated the 120-peso saving as the better deal — the larger absolute number won on the expensive item.
→ Preference flipped with price point, confirming the 100 threshold.
Common mistakes
Using one discount format everywhere
Applying a single percentage or absolute style across all price points wastes the larger-number effect on half your range.
Fixating on discounts over bonuses
Most advertisers reflexively cut price when reframing as 'more product' would produce a bigger, more persuasive number.
Is it for you?
Best for
Retail and ecommerce brands running price promotions across a range of price points.
Not ideal for
High-consideration purchases where buyers do detailed comparison maths.
From the transcript
“If you're selling a product that costs more than 100 pounds or 100 dollars or 100 euros, you should talk about your absolute discounts. If…”
“On the weeks that they talk about it being 50% more, there are 81% more sales. Even though these two things are mathematically the same.”
From the episode
8 Psychology Hacks Behind The World’s Biggest Businesses - Richard Shotton - #626
Richard Shotton