How to work out an advertising test budget
Written by the Lets Elevate team · Reviewed 2 November 2026
Choose a test budget from what you can afford to learn, rather than assuming a certain return. Separate advertising spend from training, management and page-building costs.
Start with contribution, not headline revenue
Estimate what a customer contributes after the costs of delivering the service. Then consider the proportion of qualified enquiries that become customers. Use evidence where you have it and conservative assumptions where you do not.
A fictional worked example
| Input | Illustration |
|---|---|
| Contribution per customer | £400 before advertising and overheads |
| Qualified-lead close rate | 20% |
| Expected contribution per qualified lead | £400 × 20% = £80 |
Paying £80 for each qualified lead would consume that expected contribution before overheads and profit. This is a simplified illustration, not a recommended lead price or a forecast. Leave room for uncertainty and other acquisition costs.
Write down the controls before launch
- The maximum test loss you can accept.
- The actual platform budget type and spending exposure.
- A review date and a person responsible for checking spend.
- The evidence that would make you continue, change or pause.
What if there are no sales?
Do not report a zero acquisition cost. A cost-per-customer figure is unavailable when the denominator is zero. Record the spend, review the journey and lead quality, and consider the length of your sales cycle.
Next: build a campaign brief and test the landing page.