CPC and CTR calculator
CPC = spend ÷ clicks. CTR = clicks ÷ impressions × 100. CPM = spend ÷ impressions × 1,000. Spend $3,000 for 450 clicks off 60,000 impressions and you are at $6.67 per click, a 0.75% click-through rate, and $50.00 per thousand impressions.
Three numbers in, three metrics out
Platform spend for the period you are looking at.
Clicks the platform charged you for.
Times the ad was served, whether or not anyone looked.
The price of one visitor. Quality of that visitor is a separate question.
How relevant the ad looked to the people it reached.
What the auction charges for attention, before anyone clicks.
Click-through rate in whole clicks, which is easier to argue about.
Same impressions, same spend. Cost per click would fall to $5.88.
At a fixed CPM, cost per click moves inversely with click-through rate — $3.33 a click cheaper here. Better creative is a discount.
How to use this calculator
Pull spend, clicks and impressions for one campaign over one period and enter all three. People check these metrics as a set because each one on its own is easy to misread, and the results update as you type. Keep the period identical across all three boxes — last month impressions against last week spend produces a number that means nothing.
Compare campaigns of the same type only. A search campaign and a social campaign will always produce wildly different click-through rates, because one is answering a question someone typed and the other is interrupting a scroll. Judge each against its own history.
A worked example
A plumbing company spends $3,000 on search ads in a month. The ads were served 60,000 times and produced 450 clicks.
Cost per click is $3,000 ÷ 450 = $6.67. Click-through rate is 450 ÷ 60,000 = 0.75%. CPM is $3,000 ÷ 60,000 × 1,000 = $50.00.
Next month cost per click rises to $8.00 and the owner assumes the auction got more expensive. But CPM is unchanged at $50.00 and click-through rate has fallen to 0.63%. The auction did not change — the ad stopped working. That is a creative problem with a cheap fix, and lowering the bid would have made it worse.
Reading the three together
- CPM up, CTR flat. The auction got more expensive. More competitors, a seasonal spike, or a broader audience. Nothing wrong with the ad.
- CPM flat, CTR down. Creative fatigue or a targeting drift. The same people are seeing the same ad and have stopped caring. Refresh the ad before touching the bid.
- CPM down, CTR down, CPC flat. You are being served into cheaper, less relevant placements. The click price looks stable while the traffic quality quietly falls.
- Everything improving but jobs flat. The ads are fine and the problem is downstream — the landing page, the response time, or the offer. No amount of click optimisation fixes that.
The common mistake
Chasing a lower cost per click. It is the easiest metric in an ad account to improve and the easiest to improve destructively: broaden the keywords, accept cheaper placements, and the number drops immediately while cost per booked job climbs. The clicks got cheaper because the people clicking got further from buying.
The honest version of the same goal is raising click-through rate at a stable CPM, which lowers cost per click without touching who sees the ad. That comes from creative and message match, not from bidding.
Clicks are the start of the chain, not the end of it. Work out what those clicks need to produce with the ad budget calculator, confirm a new ad genuinely beat the old one with the A/B test significance calculator, and find out what a job actually costs with the cost per booked job calculator.
Common questions
What is cost per click?
Cost per click is total ad spend divided by the number of clicks that spend bought. Three thousand dollars producing four hundred and fifty clicks is a cost per click of $6.67. It is the price of one visitor, and on its own it says nothing about whether those visitors were worth having — a cheap click from the wrong audience costs more than an expensive one from the right one.
What is click-through rate?
Click-through rate is clicks divided by impressions, expressed as a percentage. Four hundred and fifty clicks from sixty thousand impressions is a 0.75% click-through rate. It measures how relevant the ad looked to the people who saw it, which makes it the fastest read on whether targeting and creative are matched to the audience.
What is CPM and why does it matter alongside CPC?
CPM is the cost of one thousand impressions: spend divided by impressions, times a thousand. It measures what the auction is charging for attention, independent of whether anyone clicked. Reading it next to cost per click separates two different problems — a rising CPM means the auction got more expensive, while a stable CPM with a rising cost per click means the ad stopped being interesting.
How are CPC, CTR and CPM related?
They are three views of the same three numbers, and the identity linking them is that cost per click equals CPM divided by ten, divided by click-through rate as a percentage. That relationship is why click-through rate is worth improving: at a fixed CPM, doubling click-through rate halves cost per click without any change to bidding, budget or targeting.
What is a good click-through rate?
It depends almost entirely on placement and intent. Search ads shown to someone actively typing a problem attract far higher rates than social ads interrupting a feed, so the two cannot be judged against the same bar. The useful comparison is against your own campaigns over time and against the other advertisers in your auction, not against a published cross-industry average.
Why does cost per click rise over time?
Usually one of three reasons: more advertisers entering the same auction, an ad that has been running long enough that the audience has stopped noticing it, or targeting broadened into less relevant placements. Checking CPM and click-through rate separately identifies which one it is, because auction pressure moves CPM while creative fatigue moves click-through rate.
Should contractors optimise for a lower cost per click?
Only when the traffic quality is holding steady. Cost per click is easy to lower by bidding on broader, cheaper terms, and that reliably raises cost per booked job, because the extra visitors are researching rather than buying. Judge campaigns on what a booked job costs, and treat cost per click as a diagnostic for why that number moved rather than as a target.
How many clicks does it take to get a job?
Multiply the click-to-lead rate by the lead-to-appointment rate by the close rate to get clicks per job. A site converting five percent of clicks to leads, forty percent of leads to attended appointments and thirty percent of those to jobs needs roughly one hundred and sixty-seven clicks per job, so a $6.67 click implies over eleven hundred dollars of media behind every signed contract.
Keep going
Work backwards from a revenue goal to the monthly spend and the funnel it requires.
Free tool A/B Test Significance CalculatorBefore you call a new ad the winner, check the difference is real.
Free tool CPM CalculatorSolve the impression side on its own: any two of spend, impressions and CPM gives you the third.
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