Free tool
CPA Calculator
Work out what one customer costs you. Spend $3,000 for 264 conversions and your CPA is $11.36. Fill any two of spend, conversions and CPA, and the third is calculated for you.
Last updated: 2026-08-06
Cost per acquisition is spend divided by conversions: $3,000 across 264 conversions is a CPA of $11.36. It is the number that decides whether an ad account is a business or a hobby, because unlike everything above it in the funnel it is denominated in the same units as your margin. You can compare a CPA directly to what a customer is worth and know immediately which way the trade went.
The word acquisition is doing a lot of work, so define it before you use the number. A conversion can be a purchase, a trial start, a booked demo or a form fill, and each definition produces a completely different CPA from identical spend. A $40 cost per lead and a $40 cost per paying customer are not the same result and should never sit in the same column of a report.
The calculator links spend, conversions and CPA so you can fill any two and read the third. Spend and conversions price a month that already happened. A CPA and a budget tell you how many customers next month buys. A CPA and a customer target tell you what that target costs. Editing any field hands the calculation to the other two, so it works as a planning tool as easily as a reporting one.
CPA only becomes a decision once you have a ceiling to compare it to, and that ceiling comes from margin rather than from a benchmark. Gross margin times average order value is the most you can pay for a first purchase and still break even: a $60 order at a 40% margin leaves $24, so $24 is the line and a $11.36 CPA is comfortably under it. Without that line, a CPA is just a number that went up or down.
Fill any two fields, the third one calculates
Cost per acquisition. Edit whichever box you want to solve for and the calculation moves to the field you touched longest ago.
CPA = spend / conversions
Enter any two of ad spend, conversions and CPA to see the third.
Every benchmark and worked example this page uses is printed below, so the numbers are readable without entering anything.
Everything here runs in your browser. Nothing you type is sent anywhere and there is no email step: the platform benchmark table and the worked example below are free to read without entering anything at all.
The formula, worked three ways
One relation, solved for each of the three fields in turn. These are the same three solves the calculator above runs, printed here on real numbers so the page works with JavaScript switched off.
- 1What did one customer cost?
CPA = spend / conversions
$3,000 / 264 = $11.36
Whatever you counted as a conversion is what this prices. Change the definition from a purchase to a lead and the same spend produces a completely different number.
- 2How many customers does a budget buy?
conversions = spend / CPA
$1,000 / $11.36 = 88 conversions
Under roughly 30 to 50 conversions a month the figure is noise, so this is also the check on whether a budget is big enough to learn anything from.
- 3What does a customer target cost?
spend = CPA x conversions
$11.36 x 500 = $5,682
Compare the answer to your ceiling before you commit it: a $60 order at a 40% margin can only carry $24.00 per customer.
What a customer costs on each platform
Every figure in this table is derived rather than published. Each row chains the platform benchmark CPM, click-through rate and landing page conversion rate together, which is the same funnel the ROAS projection walks, so it carries the error of all three estimates.
| Platform | CPM | CTR | Landing page CVR | Expected CPA | Conversions on $3,000 |
|---|---|---|---|---|---|
| Meta (Facebook and Instagram) | $14.00 | 1.4% | 8.8% | $11.36 | 264 |
| Google Ads | $38.00 | 4% | 5% | $19.00 | 158 |
| TikTok Ads | $10.00 | 0.9% | 2.5% | $44.44 | 68 |
| LinkedIn Ads | $33.00 | 0.6% | 4% | $137.50 | 22 |
| Pinterest Ads | $6.00 | 0.6% | 2% | $50.00 | 60 |
Worked once, so the derivation is checkable: a thousand Meta (Facebook and Instagram) impressions cost $14.00 and produce 14 clicks at 1.4%. At a 8.8% landing page conversion rate that is 1.232 conversions, and $14.00 divided by 1.232 is $11.36.
Benchmarks are estimates blended from public advertising benchmark roundups and platform-published averages, last reviewed 2026-08-03. They are all-industry blends, so your vertical, offer and creative can move every number here. Use them as a planning starting point, not a forecast.
Where these numbers come from
Benchmarks are estimates blended from public advertising benchmark roundups and platform-published averages, last reviewed 2026-08-03. They are all-industry blends, so your vertical, offer and creative can move every number here. Use them as a planning starting point, not a forecast.
The CPA you calculate above is arithmetic on your own numbers and never touches that table: the benchmarks are only there so you have something to compare against. Nothing on this page is measured from your ad account or from any private dataset, and the derived figures are labelled as derived wherever they appear, because a number chained out of three estimates carries the error of all three.
How to make a cost per acquisition mean something
- Write down what counts as an acquisition before you compare anything. Purchases, trials, leads and demos all produce a CPA, and a report that mixes two of them is arithmetic on top of a category error.
- Set the ceiling from margin, not from a benchmark. Average order value times gross margin is the most a first purchase can cost you, and a working target at roughly 60% to 70% of that leaves the account room to absorb a bad week.
- Watch CPA against click cost and conversion rate together. CPA rising while clicks got cheaper means the landing page or the offer moved, and no amount of bid tuning will fix it.
- Give each ad set enough conversions to be readable. Somewhere near 30 to 50 a month is the point where a CPA stops being noise, and below that you are reading random variation as performance.
- Count repeat business only if you actually measure it. Paying above the first-order ceiling is defensible when you know the repeat rate and can prove it, and is how accounts quietly go broke when the repeat rate is a hope.
- Compare platform CPA to platform order value, never on its own. A $137.50 cost per acquisition is ruinous against a $60 basket and healthy against a $900 contract, which is what the same audience being expensive and valuable looks like in one number.
Frequently asked questions
How do you calculate CPA?
CPA = spend / conversions. Divide the amount spent by the number of conversions it produced: $3,000 for 264 conversions is a CPA of $11.36. Run it the other way to plan: at that CPA, 500 conversions needs about $5,682, and a $1,000 budget projects about 88.
What is a good CPA?
Any figure below your margin per customer, which makes it specific to you rather than to your industry. Work out the ceiling first: average order value times gross margin is the most a first purchase can cost. For a sense of scale, chaining the platform benchmarks together puts an expected cost per acquisition near $11.36 on Meta, $19.00 on Google, $44.44 on TikTok, $50.00 on Pinterest and $137.50 on LinkedIn, which mostly reflects who each platform is selling you rather than how well each one performs.
What is the difference between CPA, CPL and CAC?
CPA is the cost of whichever conversion you defined. CPL narrows that to a lead, so it is a CPA on a cheaper event further from revenue. CAC is the whole cost of acquiring a customer, so it carries every channel plus the salaries, tools and discounts that ads never see. An account can hit its CPA target every month and still have a CAC the business cannot afford.
Why did my CPA rise while my click costs fell?
Because the two are separated by everything that happens after the click. Cheaper traffic that converts at a lower rate raises the cost per customer even as the cost per visit falls, and that is exactly what broadening an audience or moving to cheaper placements tends to produce. Look at conversion rate and landing page behaviour before you touch the campaign.
How do I set a target CPA?
Start from the ceiling, then work below it. Multiply your average order value by gross margin to find the most you can pay and still break even on the first order: $60 at a 40% margin is $24. Set the working target at roughly 60% to 70% of that, so a bad week does not immediately put the account underwater, and only raise it above the ceiling if you can measure repeat purchases rather than assume them.
Is this calculator free, and is anything stored?
Free, ungated and entirely local to your browser. There is no email step, nothing you type is transmitted, and every derived figure and worked example on the page is server rendered, so the numbers are readable with JavaScript switched off.
See the real number instead of the estimate
Postify Ads runs campaigns across Meta, Google, TikTok, LinkedIn and Pinterest from one place, with spend, clicks and conversions from all five in a single view. This calculator prices the plan; that is where the account reports back.
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