Ad cost calculator
Turn spend, impressions, clicks and conversions into CPC, CPM, CPA, CTR and ROAS at once. Free, no account, and every number stays in your browser.
- Free, no account
- Runs in your browser
- Nothing is sent to us
Campaign numbers
Total spend for the campaign or the period.
Optional. Needed for CPM and CTR.
Optional. Needed for CPC and CTR.
Optional. Needed for CPA and conversion rate.
Optional. Revenue attributed to the campaign, for ROAS.
Fill in spend plus at least one count. Every combination that can be calculated will appear here, in your browser only.
The formulas
CPC = spend / clicks
CPM = (spend / impressions) × 1000
CPA = spend / conversions
CTR = (clicks / impressions) × 100
CVR = (conversions / clicks) × 100
ROAS = revenue / spendThe calculator takes one set of inputs and shows every metric your numbers can support. Leave a field blank and the metrics that depend on it are simply omitted rather than showing zero, because a zero you did not enter is a lie the eye believes.
The one number that decides everything
Every metric above is diagnostic. Only one is a verdict, and it is not on the list: is CPA below what a customer is worth to you?
Work out your break-even CPA before looking at anything else. For a one-off purchase, that is gross profit per sale. For a subscription, it is gross margin times expected lifetime, discounted for the fact that some of that revenue is a year away and uncertain.
Everything else tells you why CPA is where it is:
- High CPM, normal CTR. You are paying too much for the audience. The targeting is too narrow, or the auction is competitive.
- Normal CPM, low CTR. People see the ad and do not care. That is a creative and message problem.
- Good CTR, bad conversion rate. The ad promises something the landing page does not deliver. This is the most common and the most fixable.
- Good conversion rate, bad CPA anyway. The unit economics do not work at this price. No amount of optimisation fixes an audience that costs more than it returns.
Reading the chain in that order stops you from redesigning creative when the landing page is the problem.
Why your ad platform and your analytics disagree
They will, always, and by a lot. It is not a bug in either.
Attribution windows differ. A platform crediting a conversion to a click from twenty-eight days ago will report it; your analytics, looking at the session that actually converted, will credit whatever brought that session.
View-through conversions. Most ad platforms count people who saw the ad and later converted without clicking. Analytics never sees those, because from its side nothing happened.
Self-attribution. Each platform decides for itself whether it caused a conversion. Run three platforms and the sum of their reported conversions will comfortably exceed your actual total.
Blocking and consent. Cookie-based analytics loses conversions from people who declined the banner or run an ad blocker, so it undercounts a real conversion that the platform correctly recorded.
The practical answer is to pick one source as the number you plan against, usually your own, and use the platforms for relative comparisons within themselves.
Tag the links so the numbers are yours
None of this works if the traffic arrives untagged. Consistent campaign parameters are what let you compare a platform’s reported cost against conversions you observed yourself. The UTM builder enforces the casing and naming rules that make campaign reporting hold together, and the conversion rate calculator covers the on-site half of the funnel.
sonex reports campaign traffic and revenue against your own data, without cookies and without a consent banner, so the conversions you count are the ones that actually happened on your site.
Frequently asked.
- How do you calculate CPC, CPM and CPA?
- CPC is spend divided by clicks. CPM is spend divided by impressions, multiplied by one thousand. CPA is spend divided by conversions. All three answer the same question at a different stage of the funnel, which is why it helps to see them together.
- What is the difference between CPM and CPC?
- CPM prices attention and CPC prices interest. CPM is what you pay for a thousand people to see the ad; CPC is what you pay for one of them to click. A campaign can have a great CPM and a terrible CPC, which tells you the creative is being seen and ignored.
- What is a good ROAS?
- There is no universal number, because it depends on your margin. ROAS of 3x is excellent at 80% gross margin and loss-making at 25%. The useful threshold is your own break-even, which is one divided by your gross margin. Compare against that, not against a benchmark from another industry.
- Why does my ad platform report more conversions than my analytics?
- Ad platforms count conversions they believe they influenced, including view-through conversions where nobody clicked, and they attribute using their own window. Analytics counts what it observed on your site. Both are internally consistent and neither is lying; they answer different questions.
- Should I optimise for CPC or CPA?
- CPA, nearly always. A cheap click that never converts costs you more than an expensive click that does. CPC is only the right target when you are buying traffic for a goal you cannot measure directly, such as brand awareness.