Google Ads reports dozens of columns. Most of them are useful for diagnosing problems; only a few tell you whether your advertising is actually working. Mixing the two is how teams end up celebrating a higher click-through rate while the cost of each sale quietly doubles.
PPC KPIs (key performance indicators) are the handful of numbers you agree to judge campaigns by. Everything else is supporting evidence.
This guide sorts PPC metrics into business KPIs, efficiency metrics and diagnostic metrics, gives formulas and dated benchmarks, and shows you how to build a one-page report in 2026.
Key Takeaways
- Pick one primary KPI per campaign: cost per acquisition for lead generation, ROAS for ecommerce.
- Efficiency metrics (CPC, CTR, conversion rate) explain why the primary KPI moves.
- Diagnostic metrics (Quality Score, impression share, search terms) show where to fix things.
- Benchmarks are only useful when they are dated and sourced; your own trend matters more.
- Bad conversion tracking makes every KPI wrong – audit it first.
The three layers of PPC metrics
| Layer | Metrics | Question it answers |
|---|---|---|
| Business KPIs | Conversions, CPA, ROAS, revenue, profit, lead-to-sale rate | Is advertising making us money? |
| Efficiency metrics | CPC, CTR, conversion rate, cost, impressions | Why did the KPI change? |
| Diagnostic metrics | Quality Score, impression share, lost IS (budget/rank), search terms, Ad Strength | Where exactly should we fix things? |
Business KPIs
1. Conversions
The number of valuable actions – purchases, qualified leads, calls. Define them carefully in conversion tracking and mark only true business outcomes as primary. Micro-actions such as scroll depth belong in GA4 as secondary key events at most.
2. Cost per acquisition (CPA)
CPA = cost ÷ conversions. The main KPI for lead generation. Our full guide to cost per acquisition covers how to calculate a target CPA from your margins.
3. Return on ad spend (ROAS)
ROAS = conversion value ÷ cost. The main KPI for ecommerce. See how to calculate and improve ROAS.
4. Lead-to-customer rate and cost per customer
For lead-gen businesses, a cheap lead that never buys is expensive. Import CRM outcomes with offline conversion tracking so you can measure cost per sale, not just cost per form.
Efficiency metrics
- Cost per click (CPC) = cost ÷ clicks. Rising CPCs often mean more competition; see cost per click.
- Click-through rate (CTR) = clicks ÷ impressions. A measure of ad relevance and appeal; see our CTR benchmarks guide.
- Conversion rate = conversions ÷ clicks (or interactions). Mostly a landing page and offer metric.
- Cost and impressions – spend pacing and visibility.
These three combine neatly: CPA = CPC ÷ conversion rate. If CPA rises, check whether CPC went up or conversion rate went down – the fix is different.
Dated benchmarks for context
| Metric (Google search, US) | 2025 report (Apr 2024–Mar 2025) | 2026 report (Apr 2025–Mar 2026) |
|---|---|---|
| CTR | 6.66% | 6.64% |
| CPC | $5.26 | $5.42 |
| Conversion rate | 7.52% | 8.18% |
| Cost per lead | $70.11 | $66.69 |
Source: WordStream Google Ads Benchmarks reports for 2025 (16,446 campaigns) and 2026 (13,474 campaigns); figures are medians across industries. Industry figures vary widely, so compare like with like.
Diagnostic metrics
Quality Score
Quality Score (1–10) summarises expected CTR, ad relevance and landing page experience at keyword level. It is useful for spotting weak keywords, but it is not a goal in itself.
“Quality Score is not an input in the ad auction.”
— Google Ads Help, About Quality Score for Search campaigns
Our guide to Google Ads Quality Score explains how to improve each component.
Impression share and lost impression share
Search impression share shows what proportion of eligible impressions you received. “Lost IS (budget)” means you ran out of money; “Lost IS (rank)” means your bids or ad quality were too low. This pair tells you whether to raise budget or improve ads.
Search terms
The search terms report shows what people actually typed. It is the single best place to find wasted spend.
KPIs by campaign type
Different campaign types do different jobs, so the primary KPI should change with them. Judging a prospecting video campaign on last-click CPA, for example, will almost always make it look worse than it really is, while judging brand search on CPA will make it look better than it deserves.
| Campaign type | Primary KPI | Supporting metrics |
|---|---|---|
| Non-brand search (lead gen) | CPA or cost per qualified lead | Conversion rate, impression share, search terms |
| Shopping / Performance Max | ROAS or profit | Conversion value, product-level performance |
| Brand search | Impression share and cost | CTR, competitor activity |
| Remarketing | CPA or ROAS | Frequency, audience size |
| Demand Gen / video prospecting | Cost per new customer, assisted conversions | Reach, view rate, branded search lift |
How to choose your PPC KPIs (step by step)
- Write the business goal in one sentence (e.g. “20 booked surveys a month under £120 each”).
- Pick one primary KPI that matches it – CPA, ROAS or cost per customer.
- Set the target from your margins, not from an industry average.
- Pick two or three efficiency metrics that explain the KPI.
- List the diagnostics you will check when a KPI goes off track.
- Audit tracking so conversions are counted once and only for real outcomes.
- Build a one-page report and review it on a fixed schedule.
A simple monthly PPC report
- Spend, conversions, CPA or ROAS – this month vs last month vs same month last year
- Top five campaigns by spend with their KPI
- Impression share lost to budget and rank
- Top wasted search terms added as negatives
- Tests run and what was learned
- Actions for next month
A shared marketing dashboard makes this report self-serve for stakeholders.
Common mistakes
- Optimising for clicks. CTR and CPC look good while conversions fall.
- Counting every micro-action as a conversion. Inflated conversions make CPA look healthy when it is not.
- Chasing Quality Score. It is a diagnostic, not a KPI.
- Comparing against undated benchmarks. Always check the year and sample behind a number.
- Judging daily. Low-volume accounts need weeks of data before decisions.
- Ignoring lead quality. Import sales outcomes where you can.
Related Guides
- Cost Per Acquisition (CPA): Calculate and Reduce It
- Click-Through Rate: What’s Good and How to Improve It
- Google Ads for Small Businesses: A Practical Plan
Frequently Asked Questions
What is the most important PPC KPI?
For most businesses it is cost per acquisition (for lead generation) or return on ad spend (for ecommerce), because they connect ad spend directly to business results.
What is the difference between a PPC metric and a KPI?
A metric is any number the platform reports. A KPI is the small set of metrics tied to your business goal that you use to decide whether a campaign is working.
Is Quality Score a KPI?
No. Google says Quality Score is not an input in the ad auction. Use it to find problems with relevance or landing pages, not as a goal.
How often should I review PPC KPIs?
Check spend and conversions weekly, and review CPA, ROAS and trends monthly. Short windows are noisy, especially for low-volume accounts.
What is a good CTR for Google search ads?
WordStream’s 2026 benchmarks (US search campaigns, April 2025–March 2026) report a median CTR of 6.64% across industries, but good depends on your industry, keywords and ad positions.
Conclusion
Good PPC reporting is short: one primary KPI, a few metrics that explain it, and diagnostics you check only when something moves. Get conversion tracking right and the rest follows. If you want a team that reports on revenue rather than clicks, see our PPC management services or get a free quote. For a full account health check, start with our PPC audit checklist.
