Quality Score Formula: How It’s Calculated

This calculator works out a quality score from three weighted factors—click-through rate, relevance, and landing page experience—that advertising platforms use to rank ads. You enter the three component scores (each on a 1–10 scale), and the calculator returns a weighted overall score on the same scale, along with a simple average for comparison. The formula below is the general structure used by major ad platforms, though the exact weights are proprietary and vary by platform.

Formula

The general quality score formula is:

Quality Score = (CTR score × 0.5) + (Relevance score × 0.3) + (Landing page score × 0.2)

Where:

• CTR score (1–10): expected click-through rate compared to other ads in the same position.
• Relevance score (1–10): how closely your ad copy and keywords match the user’s search intent.
• Landing page score (1–10): how relevant and user-friendly your landing page is for the query.

The weights (0.5, 0.3, 0.2) are not officially published; they reflect the common understanding that CTR is the most heavily weighted factor. Some platforms use different scales or combine factors non-linearly.

Worked Example

Using the default values from the calculator:

1. CTR score = 7, Relevance = 8, Landing page = 6.
2. Weighted score = (7 × 0.5) + (8 × 0.3) + (6 × 0.2) = 3.5 + 2.4 + 1.2 = 7.1.
3. Rounded to one decimal: 7.1.

The simple average would be (7 + 8 + 6) / 3 = 7.0, showing how the weighting changes the result.

How Quality Score Works

Quality Score is a diagnostic tool used by search engines and social media platforms to estimate the quality of your ads. It influences two things: your ad rank (position) and your actual cost per click. A higher quality score can lead to better ad positions at lower costs, because platforms reward relevance. The score is calculated in real time based on historical performance, and it updates as your ads accumulate data. Each keyword in your account gets its own quality score, so a campaign with many keywords will have multiple scores.

How to Choose the Right Weights

Since the exact weights are proprietary, you can use the calculator with the default weights to get a reasonable estimate. If you want to experiment, adjust the weights to see how sensitive the score is to each factor. For example, if you believe CTR is even more important, you could try 0.6, 0.2, 0.2. However, for most practical purposes, the default weights are a good starting point because they align with industry consensus.

Common Mistakes and Misconceptions

• Mistaking the score for a direct ranking: Quality Score is not the same as ad rank; it’s one component of it.
• Assuming the score is static: It changes frequently based on recent performance.
• Ignoring the landing page: Many advertisers focus only on CTR and relevance, but the landing page experience is a significant factor.
• Using the simple average: The weighted formula is more accurate because it reflects the actual importance of each factor.

Limitations of the Formula

The formula is an approximation. Platforms like Google Ads and Meta don’t publish their exact algorithms, and they may use non-linear models or additional factors like device performance, ad format, and user context. Also, the component scores (CTR, relevance, landing page) are themselves estimates based on complex signals, not just the numbers you see in your account. Therefore, treat the calculated score as a rough guide, not a precise prediction.

Alternatives and Related Metrics

If you’re looking for a broader view of ad performance, consider these metrics:

• Ad Rank: The actual position of your ad, which combines your bid and quality score.
• Click-through rate (CTR): The percentage of impressions that result in clicks.
• Conversion rate: The percentage of clicks that lead to a desired action.
• Cost per acquisition (CPA): The average cost of a conversion.

These metrics together give a more complete picture than quality score alone.

Frequently Asked Questions

What is a good quality score?

A score of 7 or above is generally considered good, indicating that your ads are relevant and your landing page is user-friendly. Scores below 5 suggest significant room for improvement.

How often is quality score updated?

Quality score is typically updated in real time as new data comes in, but you may see changes in your account within a few hours to a few days. It’s based on rolling performance over the past 30 days.

Does quality score affect cost per click?

Yes, a higher quality score can lead to a lower cost per click because the platform rewards relevant ads with discounts. The exact discount varies by platform and auction dynamics.

Can I improve my quality score quickly?

Improving CTR and relevance can be done relatively quickly by refining ad copy and keywords, but landing page changes may take longer to reflect. Expect to see improvements within a few weeks of consistent optimization.

Is quality score the same across all platforms?

No, each platform has its own version. Google Ads, Microsoft Advertising, and Meta all use similar concepts but with different scales and calculations. Always refer to the specific platform’s documentation.

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in ctr | Click-through rate score | 1-10 | 7 | 1
in rel | Relevance score | 1-10 | 8 | 1
in lp | Landing page experience | 1-10 | 6 | 1
out weighted | Weighted quality score | /10 | (ctr * 0.5 + rel * 0.3 + lp * 0.2) | 1
out simple | Simple average | /10 | (ctr + rel + lp) / 3 | 1