Percent off or a fixed discount on a landing page: what the "rule of 100" says

A $89 template drops to $59 with a promo code. Two ways to announce the same discount on the landing page: "$30 off" or "34% off". The final price doesn't change by a cent depending on the format, but how the offer is perceived shifts noticeably — and not randomly. It's a framing problem studied in price marketing since the late 1990s, with a sharper answer than a simple "it depends".

The "rule of 100": a threshold, not a preference

The reference study on the topic is by Haipeng (Allan) Chen, Kent B. Monroe and Yung-Chien Lou, published in 1998 in the Journal of Retailing (available on Google Scholar). The authors show that which discount reads as the better deal depends on a simple threshold: below 100 (currency units), a percentage looks bigger than the equivalent fixed amount; above 100, it flips — the fixed amount is more impressive. Their own example still lands well: a $0.50 can of soda cut by 50% (a real saving of $0.25) looks like a great deal, while a $20,000 car cut by $1,000 (5%) already looks generous framed in dollars, but noticeably less impressive framed as a percentage. This informal benchmark eventually earned a name in the marketing literature: the rule of 100.

The logic underneath isn't mysterious: a percentage gets judged relative to the reference price ("how much do I get back"), a fixed amount gets judged in absolute terms ("how much do I actually save"). Below 100, the percentage always produces the larger of the two numbers; above 100, the fixed amount wins. The brain keeps the higher number, not the more honest format — which ties into what we cover in our article on price anchoring: the first number a visitor sees sets the frame for everything that follows.

One nuance: the format also shapes what happens after the promotion

A percentage discount isn't neutral once the promotion ends. A study by Devon DelVecchio, H. Shanker Krishnan and Daniel C. Smith, published in 2007 in the Journal of Marketing (available on Google Scholar), shows that for deep discounts, percentage framing raises future price expectations more than an equivalent fixed-amount framing does — and shapes the purchase decision once the promotion lifts. For a one-off purchase like a downloadable template, this nuance barely matters: the transaction closes once. It matters much more for anything recurring — a free trial that rolls into a monthly subscription, a "20% off your first year" SaaS offer. Announcing a percentage there sets a price expectation you'll have to live up to at renewal, a trap we cover in our article on how long a SaaS free trial should run.

Applying the rule on a landing page: three concrete cases

• A single product under $100 — a LanderKit template at $89, cut by $30, works out to 34% off. Both formats are true, but the percentage looks more generous while requiring mental math to recover the final price; the fixed amount ("$30 off", code SEMAINE30) stays instantly checkable, which matters more when a visitor is comparing several templates within seconds.
• A bundle above $100 — the full pack at $229 cut by $80 (code PACK149) illustrates the other side of the threshold: showing "$80 off" lands harder than showing "35% off", exactly what the rule of 100 predicts, even though the amount saved is identical either way.
• A recurring subscription — for a free trial that rolls into a monthly plan, like on our SaaS Waitlist template, discount depth matters more than the 100 threshold: a "50% off your first month" sets a price expectation you'll have to live up to at renewal, while a fixed euro amount leaves no such trail.

Where to show it, and how honestly

Whichever format you pick, it doesn't waive any of the credibility rules for a struck-through price: the reference price shown next to the discount has to have genuinely existed, or the offer crosses the line we cover in our guide on crossed-out prices and credible discounts — and sometimes a legal line, in jurisdictions that regulate how sales and promotions can be displayed. Inflating the reference price so that the discount, whatever its format, looks more dramatic falls under the dark patterns that Google and consumer authorities are increasingly cracking down on.

Two mistakes that hurt credibility, whichever format you choose

• Making the visitor do the math. Showing a percentage alone, without the final price next to it, adds a mental calculation step before the decision — a cognitive load that rarely helps conversion. The final struck-through-versus-real price should always be visible, no matter which format frames the discount itself.
• Switching formats mid-funnel. Announcing "34% off" on the landing page and then showing "$30 off" at checkout creates a micro-inconsistency that, even when mathematically correct, forces the visitor to double-check something they'd already accepted — an unnecessary friction point right before conversion.

Settle it with a test rather than a rule of thumb

The rule of 100 is a solid benchmark, not a universal law: the real threshold shifts with the market, the currency, and the audience's habits. When a price sits near the 100 mark, or for any high-stakes offer, an A/B test settles the question more reliably than a hunch. If traffic doesn't allow for statistical significance, our article on A/B testing without much traffic covers how to decide anyway, without leaving it to chance.

LanderKit's own rotating offers apply this logic without exception: every promo code — SEMAINE30, PACK149, CATALOGUE15 — is a fixed euro amount, never a percentage, precisely because every price in the catalog sits above or right at the $100-ish threshold where the fixed amount wins out. That same final price, discount already applied, is what shows up on every template page and on the full pack page.