If you’ve used the calculator on this site, you’ll have noticed that we estimate your Google Ads Quality Score from your PageSpeed result. A reasonable question is: how does a website speed score translate into an ad cost multiplier?
The honest answer is that it doesn’t, not directly. PageSpeed and Quality Score are not the same number, and Google has never published a formula that converts one into the other. What we can say is that PageSpeed is the strongest measurable proxy for the component of Quality Score that your website controls. Here’s why that matters, and why the estimate holds up.
Quality Score Has Three Components
Google calculates Quality Score from three inputs, each rated as “Below Average,” “Average,” or “Above Average”:
- Expected Click-Through Rate: How often Google predicts your ad will be clicked when shown for a given keyword, based on historical performance.
- Ad Relevance: How closely your ad copy matches the intent behind the search query.
- Landing Page Experience: How useful, relevant, and fast your landing page is for the person who clicked.
Each component carries roughly equal weight. A “Below Average” rating on any one of them drags the overall score down significantly. An “Above Average” rating on any one of them lifts it.
The first two components (CTR and Ad Relevance) are determined almost entirely by how your Google Ads campaigns are structured and written. Your website has little influence on them.
Landing Page Experience is the component your website controls.
What Google Evaluates for Landing Page Experience
Google evaluates landing pages on several factors:
- Load speed on mobile: How quickly the page becomes usable on a phone
- Core Web Vitals: Specific technical measurements of loading, interactivity, and visual stability
- Mobile-friendliness: Whether the page works properly on small screens
- Content relevance: Whether the page actually addresses what the user searched for
- Navigability: Whether the user can easily find what they need
- Transparency: Whether it’s clear who you are and how to contact you
Of these, load speed and Core Web Vitals are by far the most measurable and the most impactful. Google has confirmed that page speed has been a direct ranking signal for mobile since 2018, and Core Web Vitals became official ranking factors in 2021.
Why PageSpeed Is the Best Available Proxy
Google’s PageSpeed Insights tool (which produces the 0-100 score) is Google’s own measurement of how well a page performs against their Core Web Vitals criteria. It is, quite literally, Google scoring your page by the same standards they use internally.
When Google’s algorithm evaluates your landing page for Quality Score purposes, it is measuring the same underlying signals that PageSpeed Insights measures: how fast the page loads on mobile (LCP: Largest Contentful Paint), how stable the layout is while loading (CLS: Cumulative Layout Shift), and how quickly it responds to interaction (INP: Interaction to Next Paint).
This is why PageSpeed score is a strong proxy for Landing Page Experience. They are measuring the same thing using the same criteria. A page that scores 25 on PageSpeed is telling Google that it loads slowly, performs poorly on mobile, and fails Core Web Vitals, which maps directly to a “Below Average” landing page experience rating.
The Mapping We Use and Its Limits
In the calculator on this site, we map PageSpeed scores to estimated Quality Score ranges as follows:
| PageSpeed Score | Estimated QS | Landing Page Experience |
|---|---|---|
| 95+ | 7 to 8 | Above Average |
| 75 to 94 | 6 | Average |
| 50 to 74 | 5 | Below Average |
| 20 to 49 | 4 | Poor |
| Below 20 | 3 | Very Poor |
These ranges are estimates, not precise calculations. There are two important caveats:
Caveat 1: PageSpeed captures most but not all of Landing Page Experience. Content relevance, navigability, and transparency also contribute. A fast page that has nothing to do with what the user searched for will still receive a poor landing page experience rating. The sites we build are designed to address all of these factors, not just speed.
Caveat 2: Landing Page Experience is only one of three QS components. Even a perfect landing page experience rating of “Above Average” will not lift a poorly structured campaign. If your ad copy is irrelevant to the keyword, or your historical CTR is low, the final Quality Score will be lower than the landing page experience component alone would suggest.
This is why we frame the calculator result as an estimate based on the most significant and measurable factor, not a guaranteed output.
Why the Estimate Is Still Useful
Despite these caveats, the PageSpeed-to-QS estimate holds up well for one simple reason: for most plumbing websites, a poor PageSpeed score is the dominant cause of a poor Quality Score.
The average plumbing website scores in the 20 to 72 range on PageSpeed for mobile. At that level, the landing page experience is almost certainly rated “Below Average,” and this single rating pushes the Quality Score into the 4 to 5 range regardless of how well the other two components are performing. You cannot have an “Above Average” landing page experience with a PageSpeed score of 25. The two are incompatible.
Conversely, fixing the PageSpeed score to 90+ shifts landing page experience to “Above Average” across the entire account. This single change is the highest-leverage improvement available to most plumbing advertisers, which is why it is where we start.
The other two components (CTR and Ad Relevance) require ongoing campaign management to optimize. They cannot be fixed by a website change alone. But they also cannot compensate for a poor landing page. The site is always the foundation.
The Honest Framing
The calculator gives you an estimate of the Quality Score range your PageSpeed score is likely producing, and what that range is costing you in Google Ads penalty. It is not a guarantee of your exact score. Only Google knows that, and even then it varies by keyword and changes over time.
What the estimate reliably shows is the order of magnitude of the problem. A site scoring 30 on PageSpeed is not paying a small penalty. It is paying several hundred percent above the market rate on every click it buys. The exact multiplier might be 50% or 100%, but it is not zero. That is the point worth understanding.
Sources: Google Search Central, “Page Experience Update” (2021). Google Ads Help, “About Quality Score” (support.google.com/google-ads/answer/6167118). Google Search Central, “Evaluating page experience for a better web” (2021). Think with Google, “Find out how you stack up to new industry benchmarks for mobile page speed” (2018).