What is Cost Per Acquisition (CPA)?

CPA is the total ad spend divided by the number of conversions. A conversion can be a purchase, sign-up, form fill, or any goal you define. Lower CPA means each conversion costs less.

It depends on your product margin and average order value. A rule of thumb: CPA should be below 30% of the revenue per conversion. Use the break-even field to find your exact threshold.

How is ROAS calculated?

ROAS (Return on Ad Spend) = Total Revenue / Total Ad Spend. A ROAS of 3 means you earned $3 for every $1 spent on ads. Most e-commerce businesses target a ROAS of 2–5x depending on margins.

What is break-even revenue per conversion?

Break-even revenue per conversion equals your CPA — it is the minimum revenue each conversion must generate to recover the ad spend. If your average order value is above this number, your campaign is profitable.

How do I lower my CPA?

Improve ad targeting to reach higher-intent audiences, optimize landing page conversion rate, test ad creatives, exclude poor-performing placements, and adjust bids based on conversion data.

Can I use this for non-e-commerce campaigns?

Yes. CPA applies to any campaign goal: lead generation, app installs, newsletter sign-ups, free trial activations, etc. Just define what counts as a conversion and enter the corresponding numbers.

CPA Calculator

Enter your ad spend and conversions to calculate CPA, ROAS, and break-even revenue per conversion.

Campaign Inputs

Total Ad Spend ($) *

Number of Conversions *

Total Revenue ($) (optional — for ROAS)

Target CPA ($) (optional — for volume goal)

Enter your ad spend and conversions, then click Calculate CPA.

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Summary

Enter your ad spend and conversions to calculate CPA, ROAS, and break-even revenue per conversion.

How it works

Enter your total ad spend for the campaign period.
Enter the number of conversions (purchases, sign-ups, leads, etc.).
Optionally enter total revenue generated to calculate ROAS.
Optionally enter your target CPA to see how many conversions you need.
Results update instantly — CPA, ROAS, break-even, and efficiency rating.

Use cases

Evaluate Google Ads or Meta Ads campaign efficiency.
Set CPA targets before launching a paid campaign.
Compare CPA across multiple ad sets or channels.
Calculate break-even revenue needed per conversion.
Report campaign ROI to clients or stakeholders.
Determine budget adjustments to hit a target CPA.
Audit historical campaigns for profitability.
Benchmark e-commerce ad performance against industry norms.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu