Free calculators
Do the maths before you spend on ads.
Three calculations we make before any budget: the ROAS below which you lose money, the budget that brings the number of customers you want, and the real cost of a customer. Fields start with the illustrative examples from our guides; replace them with your own numbers.
What ROAS do you need to not lose money?
ROAS measures revenue, not profit. The threshold comes from your contribution margin: what is left of an order after goods, shipping, fees and returns.
- Contribution margin
- 35%
- Break-even ROAS
- 2.86
- Target ROAS
- 4.00
- Threshold in the platform, if values include VAT
- 3.46
Below break-even ROAS, every order from ads costs you money. If the platform receives order values including VAT, reported ROAS is inflated, so compare against the last row inside the platform.
Full guide: break-even ROAS →How much budget for how many customers?
Don't start from a "typical" CPM. Start from what you can afford to pay for a customer and how many leads become customers.
- Left per sale after CAC
- 30 €
- Maximum cost per lead
- 5 €
- Leads needed per month
- 80
- Monthly budget
- 400 €
- Daily budget (approx.)
- 13 €
Monthly budget = customers wanted × maximum CAC. Maximum cost per lead = maximum CAC × lead-to-customer rate. Take the rate from your real sales, not from market averages.
Full guide: how much Facebook and Instagram ads cost →What does a new customer really cost?
Cost per lead shows what you pay for a contact. CAC shows what you pay for a customer who bought, with all acquisition costs of the same month.
- Cost per lead
- 20 €
- CAC from ads only
- 667 €
- Full CAC
- 1,000 €
- Lead-to-customer rate
- 3.0%
Compare campaigns by cost per customer, not cost per lead: a cheap lead is not a cheap customer. Assign customers to the month the lead came in, not the month the contract was signed.
Full guide: cost per lead vs customer acquisition cost →The calculation runs only in your browser. Your numbers are not saved or sent anywhere.
Frequently asked questions
What is a good ROAS for an online store?
There is no universal good ROAS. A ROAS is good if it is above your break-even point, which comes from your margin: break-even ROAS = 1 ÷ contribution margin. At a 35% margin the threshold is about 2.86; at 50% it is 2.
Why is platform ROAS higher than real ROAS?
Because the platform may receive order values including VAT and shipping, and each platform attributes conversions by its own rules. Compare the threshold with the value sent to the platform, and check budget decisions against real sales.
How do I find my lead-to-customer rate?
From your CRM or a simple sheet: how many leads came in during a month and how many became customers in the following 30–90 days. Without the lead source saved, you can't calculate it per campaign.
What goes into full CAC?
Ad spend plus the fixed acquisition costs of the same period: agency fee, tools, creative and sales-team time, divided by the new customers from the same lead cohort.
Start the diagnostic
Want these calculations on your real data?
The free 3-minute diagnostic shows where your acquisition breaks: ads, website, form or measurement.