One of the most effective ways to influence a shopper is savings. Put a real discount in a title tag, meta description, H1, or caption, and you give the searcher an incentive to act, and a reason to trust you when they see the same number on the page that drew them in from the search result. Incentives compel people to act, and savings is about the most powerful incentive there is.
But savings is one of those signals that helps enormously when done right and quietly hurts when done wrong. The whole game is knowing which number to show, and when to show nothing.
The number is already in your data
You need exactly two fields to calculate savings, and you already have both: MSRP and sale price. The math is one line, done in code, in the database, or on the fly:
List pages show the single highest savings percentage across the products in the list ("Up to X% Off"). Product pages show that one item's exact savings. Same calculation, two presentations.
The 10% rule, tested and retested
Here is the finding that makes this work: on the web, a discount needs to be at least 10% to compel someone to click. This has been tested and retested. Below 10%, showing the percentage does not just fail to help, it can actively work against you. "8% Off" reads like the store is bragging about nothing. But here is the subtlety most people miss: that same 8%-off item might still have a savings worth shouting about, in dollars. The rule is not "only show big discounts." It is "show the number that compels, and the dollar amount is often it." Same product, same price, two ways to display it:
✓ Show the number that compels
Trail Running Shoes, $46.00 · Save $4.00
Hiking Backpack, $228.00 · Save $12.00
✗ Show the weak percentage
Trail Running Shoes, $46.00 · 8% Off
Hiking Backpack, $228.00 · 5% Off
Look at the shoes: $50 down to $46. That is 8% off, which is under the threshold and reads as nothing, but it is also four dollars, and "Save $4.00" feels like a deal. The backpack is the same story magnified: 5% off sounds trivial, yet it is twelve real dollars off. Identical products, identical prices. The only difference is which number you chose to put in front of the shopper, and the dollar figure wins both times. When you hand someone "8% Off," you have told the truth in the least compelling way possible.
When this function was first deployed, before the logic was fully vetted, visitors actually complained about listings advertising a tiny percentage off. That feedback shaped the rule below, which has now run for over five years.
The algorithm: percentage, then dollars, then quiet
So savings is not a single number you always show. It is a tiered decision. The function asks, in order, which form of the savings is worth displaying, and falls back gracefully when none is:
Read it as a cascade. A 30%-off jacket ($180 down to $126) clears the threshold, so it shows "30% Off." The 8%-off shoes fall through to the next rung and show "Save $4.00." A trivial few-cents markdown drops to a quiet "On Sale." And an item with no real discount shows nothing. Product pages use the same logic with the exact figure rather than "up to," since a single product has one true savings number.
Why "show nothing" means literally nothing
When there are no savings worth showing, the function displays nothing, not even a blank space. This sounds pedantic until you see what an empty placeholder does to a title tag: it leaves a stray gap, a double space, a dangling separator that makes the listing look broken. So the savings shortcode collapses completely when it has nothing to say. The spacing stays clean whether the discount is there or not.
A word on honesty and the law
Because savings claims are advertising, the thresholds are not only a marketing decision, they can be a legal one. Check your state laws and talk to your attorney about what counts as deceptive. The math is unforgiving on small numbers: a grocery item with an MSRP of $1.49 marked down to $1.39 is a 6.7% saving and all of ten cents. That might be fine for a grocery store and completely inappropriate, even deceptive, for another category. The tiered rule helps here too, because it naturally suppresses the trivial discounts that are most likely to cause trouble.
The trap door
The tempting mistake is to show every discount because "a sale is a sale." It is not. A wall of "2% Off," "4% Off," "1% Off" across your listings trains shoppers to ignore your savings messaging entirely and makes the store look desperate. Discipline is the feature: show savings only where they are genuinely compelling, stay quiet everywhere else, and the discounts you do show carry real weight. The 10% rule is not a limitation. It is what keeps your savings signal credible.
The takeaway
Savings is one of your strongest incentives, but only when shown well. Calculate it from the MSRP and sale price you already store, show the percentage when it clears 10%, fall back to a dollar figure when that is the more compelling number, drop to a quiet "On Sale" for trivial markdowns, and show nothing, not even a space, when there is nothing worth saying. Run that one tiered function across the catalog and every listing carries exactly the right savings message, automatically, while staying honest and legal.
The last Insight in this Tactical section covers the SKU and model number, the unglamorous string that quietly captures some of the highest-intent long-tail searches there are.
From the book
The "Savings % and $$ Amount" chapter of Sizzle: An E-Commerce Revolution covers the savings calculation, the tested 10% threshold, the full list-page and product-page algorithms, and the legal cautions around discount claims.