Cost Per Acquisition (CPA) Calculator

Work out your cost per acquisition, how many conversions a budget will buy, or the budget you need for a target CPA. Then see the highest CPA you can afford, in any currency.

Free Marketing Tool

Cost Per Acquisition (CPA) Calculator

Work out your cost per acquisition, how many conversions a budget will buy, or the budget you need for a target CPA. Then see the highest CPA you can afford, in any currency.

1
Pick what to solve

Your CPA, conversions from a budget, or the budget needed for a target CPA.

2
Enter two numbers

The tool works out the third instantly. No calculate button needed.

3
Add your economics

Order value and margin reveal your break-even CPA and the profit each conversion leaves behind.

Your campaign numbers

Figures in

No match found.

What you spent, or plan to spend, on the campaign over the period you are measuring.
Sales, leads, sign ups or bookings, whichever counts as a completed goal for you, over the same period as the spend.
What you expect, or want, to pay for each conversion. Use your recent average from the platform if you have one.
Your target number of conversions for the period. Work backwards from a revenue goal rather than picking a round number.

Your economics optional

Average order value, or the average revenue a lead is worth. For a considered purchase, use lifetime value rather than the first order.
The percentage of each sale you keep after cost of goods and delivery. Leave at 100 for a service business with no direct cost of sale.
%
i

A high CPA is not automatically bad. It only matters relative to what a conversion is worth, which is exactly what break-even CPA below tells you.

Your cost per acquisition
—
Waiting for your numbers
Show in

No match found.

—Conversions per 1,000 spend
—Revenue generated
—Return on ad spend
Break-even CPA—
Profit per conversion—
Gross profit generated—
Net position—
Choose what you want to solve above, enter two numbers, and your result appears here instantly.
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Recent calculations 0

Nothing saved yet. Run a calculation and press Save to keep it here, then tick any two to compare them side by side.

Currency for your entered figures defaults to USD and can be changed above with no conversion applied to what you type. Live conversion, when turned on, uses real exchange rates and is shown as an approximate reference, not a guaranteed rate. Rates by ExchangeRate-API, updated once daily. Break-even assumes your close rate holds as spend changes, so treat it as a ceiling rather than a target.

Want better numbers than this?

We plan, run and optimise Google Ads and paid social campaigns that turn clicks into customers, with reporting tied to revenue.

01Overview

What is cost per acquisition (CPA)?

Cost per acquisition is what you spend in advertising to win one customer, lead or sale. It is the clearest measure of campaign efficiency because it skips the vanity metrics and goes straight to the outcome you pay for.

The free CPA calculator above works out your CPA from spend and conversions, the conversions a budget will buy, or the budget needed for a target CPA. Add your order value and margin and it shows your break-even CPA and the profit each conversion leaves behind.

CPA only makes sense next to what a customer is worth. A $90 CPA is excellent for a $2,000 service and ruinous for a $40 product.

Quick answer

CPA = total ad spend ÷ conversions. $2,000 spend that brings 40 sales is a $50 CPA. Break-even CPA = order value × profit margin, so a $150 order at 40% margin can afford up to $60 per sale.

  • Free, no sign-up
  • Break-even CPA
  • Profit per conversion
  • Any currency
02How to use

How to use the CPA Calculator

Use the same date range and the same conversion type for spend and conversions.

  1. Pick a mode

    Your CPA, conversions from a budget, or the budget needed for a target CPA.

  2. Enter spend and conversions

    Use platform-reported conversions or, better, conversions you can confirm in your CRM or store.

  3. Add order value and margin

    This reveals break-even CPA and the profit or loss on each conversion.

  4. Set a target CPA

    Use the break-even figure to set realistic targets for automated bidding.

03How it works

How CPA and break-even CPA are calculated

Two numbers matter: what each conversion costs you, and what it is worth.

The CPA equation
CPA=Ad spendConversions
$1,800 ÷ 45 = $40
Actual CPA vs break-even CPA
Your CPA
$40 per booking
Break-even CPA
$110, so $70 profit each
CPA formulasCPA = Total spend / ConversionsBreak-even CPA = Order value x Profit marginProfit per conversion = Break-even CPA - CPA

For subscriptions or repeat buyers, use customer lifetime value instead of a single order value. See the CLV calculator.

Worked example

A dental clinic runs Meta lead ads for new patient check-ups.

Spend
$1,800
Booked appointments
45
CPA
$40
Value of a new patient
$220 at 50% margin
Break-even CPA is $110, so each booking leaves about $70 profit. There is room to scale spend.
04Reference

CPA, CAC, CPL and ROAS compared

These terms overlap and are often confused in reports. Here is how they differ.

MetricFormulaBest used for
CPA (cost per acquisition)Ad spend / conversionsDay-to-day campaign efficiency
CPL (cost per lead)Ad spend / leadsLead generation before a sale is made
CAC (customer acquisition cost)All sales and marketing cost / new customersBusiness-level unit economics
ROAS (return on ad spend)Revenue / ad spendEcommerce campaigns with tracked revenue
Break-even CPAOrder value x marginSetting target CPA bids
05Tips

How to lower your CPA

CPA falls when either cost per click drops or conversion rate rises. Conversion rate is usually the bigger lever.

Do this

  • Fix the landing page firstDoubling conversion rate halves CPA. That is far easier than halving click costs.
  • Feed the algorithm real conversionsImport offline sales or qualified leads so smart bidding optimises for buyers, not form spam.
  • Exclude existing customersUpload customer lists as exclusions on prospecting campaigns to stop paying for people who already bought.
  • Cut the bottom performersPause keywords, audiences and placements that spend twice your target CPA without converting.

CPA mistakes to avoid

  • Counting low-quality leadsA $10 CPL means nothing if none of those leads buy. Measure cost per qualified lead or per sale.
  • Setting targets below realityTarget CPAs far below your current CPA starve automated campaigns of volume.
  • Ignoring lifetime valueRepeat-purchase businesses can afford a CPA above first-order profit. Judge against CLV.
  • Changing too much at onceBig budget or target changes reset learning. Adjust gradually, around 15% to 20% at a time.
06FAQ

Frequently asked questions

What is a good CPA?

Any CPA below your break-even CPA is profitable. Break-even equals order value times profit margin, or lifetime value times margin for repeat customers.

How do I calculate CPA?

Divide total ad spend by the number of conversions. $5,000 spend and 100 sales gives a $50 CPA.

What is the difference between CPA and CAC?

CPA usually covers ad spend for one campaign. CAC includes all sales and marketing costs, such as salaries, tools and agency fees, divided by new customers.

What is target CPA bidding?

A Google Ads and Meta bid strategy where the platform sets bids automatically to get as many conversions as possible at or below the CPA you choose.

Why is my CPA rising?

Common causes are ad fatigue, rising competition, a landing page change, tracking breaking, or scaling budget too fast.

Can CPA be higher than order value?

Yes, if customers buy repeatedly. Subscription businesses often accept a first-order loss because lifetime value covers it.

The Big Growth team

Want ads that pay for themselves?

We plan, run and optimise Google, Meta and LinkedIn campaigns for businesses worldwide, with reporting tied to revenue, not vanity metrics. Our Google Ads management team optimises for CPA. Explore our social media advertising services.