If you have ever stared at a Quality Score column and wondered what math produced that number, you are asking the right question. Google never publishes the exact equation. But the inputs are documented, and the point weights have been reverse-engineered — so you can get remarkably close to the real formula.
This guide walks the actual components, the point-based formula practitioners use, and the part almost every article skips: how a higher score turns into lower cost and more profit per order.
What the quality score formula measures
Quality Score is Google's rating of how relevant and useful your ad is to someone searching a given keyword. It lives at the keyword level and runs on a one-to-ten scale.
According to Google's own documentation, the score is built from three components. Each one is rated Above average, Average, or Below average, based on a comparison with other advertisers who showed for the same search over the last ninety days.
The three components are:
- Expected click-through rate — how likely your ad is to be clicked when it shows.
- Ad relevance — how closely your ad matches the intent behind the search.
- Landing page experience — how relevant, fast, and useful your page is after the click.
Notice what those ratings are: relative grades, not raw percentages. Your "Below average" is a comparison to competitors, not a fixed threshold you can look up.
The reverse-engineered quality score formula
Because the three components are graded on a three-point scale, you can translate them into points and rebuild the visible score. Adalysis reverse-engineered the point values and published this table:
| Component | Above average | Average | Below average |
|---|---|---|---|
| Landing page experience | 3.5 | 1.75 | 0 |
| Expected click-through rate | 3.5 | 1.75 | 0 |
| Ad relevance | 2 | 1 | 0 |
The formula is then simply:
Quality Score = 1 + landing page points + ad relevance points + click-through points
The base of one plus the maximums (3.5 + 3.5 + 2) sums to ten. Two things fall out of this immediately.
First, expected CTR and landing page experience each carry more weight than ad relevance — 3.5 possible points versus 2. Fixing a weak landing page moves your number nearly twice as far as fixing ad copy relevance alone.
Second, the score is coarse. Say all three components sit at Average: 1 + 1.75 + 1.75 + 1 = 5.5, which shows as a 5 or 6. Push landing page and CTR to Above average while relevance stays Average: 1 + 3.5 + 3.5 + 1 = 9. One grade change on the heavy components is the difference between mediocre and near-perfect.
Quality Score is a diagnostic, not an auction input
Here is where most guides mislead you. Google is explicit that "Quality Score is not an input in the ad auction. It's a diagnostic tool to identify how ads that show for certain keywords affect the user experience."
The auction runs on Ad Rank, calculated fresh every search. Per Google's Ad Rank documentation, it factors in your bid, the auction-time quality of your ad and landing page, the Ad Rank thresholds, how competitive the auction is, the search context, and the expected impact of your assets and formats.
So Quality Score and Ad Rank are not the same thing. Quality Score is the slow-moving report card you can read; Ad Rank is the live calculation that decides whether you show and what you pay. They rhyme — both reward relevance — but you optimize the diagnostic to influence the auction, not the other way around.
What a higher score actually buys you
The reason to care is cost. A simplified version of Google's cost math is that your cost per click roughly equals the Ad Rank of the advertiser below you, divided by your Quality Score, plus one cent — a relationship WordStream documented years ago.
Walk a quick example. Say the advertiser just below you has an Ad Rank of 4.
- At a Quality Score of 5: CPC ≈ 4 ÷ 5 + $0.01 = $0.81
- At a Quality Score of 8: CPC ≈ 4 ÷ 8 + $0.01 = $0.51
Same position, same competitor — but a better score cut your click cost by roughly a third. WordStream's larger dataset found that, on average, every Quality Score point above five drops cost per action about sixteen percent, and every point below five raises it by a similar amount. The effect is not linear; the gains sit in the upper range, so moving from seven to eight helps more than five to six.
The profit angle almost everyone skips
Lower CPC is nice. What it really changes is your break-even ROAS — the point where ad revenue exactly covers the product and the ad spend.
The identity is pure arithmetic: break-even ROAS = 1 ÷ contribution margin, where contribution margin is the share of revenue left after cost of goods, shipping, and fees. Say you sell a product at a $50 average order value on a 50% contribution margin. That leaves $25 of gross profit per order, so your break-even ROAS is 1 ÷ 0.50 = 2.0x, and you can pay up to $25 to acquire an order.
Now carry the Quality Score example through to per-order profit. Say your landing page converts 4% of clicks, so it takes 25 clicks to make one sale.
- At a Quality Score of 5 (CPC $0.81): CAC = 25 × $0.81 = $20.25 → profit ≈ $4.75 per order
- At a Quality Score of 8 (CPC $0.51): CAC = 25 × $0.51 = $12.75 → profit ≈ $12.25 per order
You did not change the product, the price, or the budget. You improved a relevance signal, and per-order profit more than doubled. That headroom is exactly what lets you keep spending profitably — the core idea in our guide to profitable ad scaling, where the number that governs scaling decisions is marginal profit, not the headline ROAS.
There is a second lever hiding in that same math. Raising average order value lifts the gross profit per order, which means a given CAC clears more easily — the mechanics are laid out in our piece on how to improve average order value. Quality Score and AOV push the same wall from opposite sides: one lowers what you pay, the other raises what each order is worth.
How to move each component
Because the formula is component-based, you fix it component by component.
Expected CTR (up to 3.5 points). This tracks how compelling your ad is for the keyword. Tighten ad groups so each keyword gets copy written for it, and lean on the highest-intent search terms rather than broad matches that attract weak clicks.
Landing page experience (up to 3.5 points). The other heavy lever. Match the page headline to the ad promise, make sure it loads fast on mobile, and keep the path to the offer short. A fast, relevant page is also cheaper attention — the same forces that push CPM around on paid social show up here, as covered in how to improve CPM.
Ad relevance (up to 2 points). Lightest weight, but the easiest to fix: get the keyword into the headline and body so the intent match is obvious.
One caution: a strong score does not immunize you against the demand-side problems that quietly erode results, like the creative wear-out described in our guide to fighting ad fatigue. Quality Score fixes the price of a click; it cannot make a tired offer convert.
Where the profit math gets hard is that Quality Score lives inside Google Ads, but your true per-order profit lives across your store, your suppliers, and your fees. PodVector connects Shopify, Meta Ads, Google Ads, Printify, Printful, and Stripe to compute your real per-order profit, and Victor — an AI operator — reads that live data to flag which keywords and offers actually clear your break-even ROAS, proposing Shopify-side moves for your approval. Victor does not touch your ad account; he tells you where the money leaks so you decide the fix.
FAQs
Is there an official quality score formula from Google?
No. Google publishes the three components — expected CTR, ad relevance, and landing page experience — and the one-to-ten scale, but never the exact weights or equation. The point-based formula in this article is reverse-engineered from observed data, not an official release.
What is a good Quality Score?
Higher is cheaper, so aim as high as the auction allows. A score of seven or above generally means your components are at or above average; anything at three or below signals at least one component is dragging and is worth an immediate look at your ad copy and landing page.
Does Quality Score directly set my ad position or cost?
Not directly. Per Google, Quality Score is a diagnostic, and the live auction runs on Ad Rank, which uses auction-time quality signals rather than the reported score. The two move together because both reward relevance, but you influence the auction by improving the components the diagnostic measures.
Which component should I fix first?
Start with landing page experience and expected click-through rate. Each is worth up to 3.5 points in the reverse-engineered formula, versus 2 for ad relevance, so a one-grade improvement on either moves your score nearly twice as far.
How fast does Quality Score change after I make improvements?
It is not instant. The component grades compare you to other advertisers over a rolling ninety-day window, so it takes accumulated impressions and clicks on the improved ad or page before the number catches up. Make the fix, then give it time and traffic to register.
Does a high Quality Score guarantee profit?
No. A high score lowers what you pay per click, but profit still depends on your conversion rate, price, and margin. A cheap click to a page that does not convert, or an order whose margin cannot cover the acquisition cost, still loses money regardless of the score.