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How to size a budget for a creative test

A test with too little budget cannot answer anything. A test with too much costs more than the lesson is worth.

Work back from results

Decide how many results per variant you need before you would trust a difference. Fewer variants need less budget.
Estimate cost per result from recent data for the same audience.
Budget per variant = results needed x cost per result.

Example with made-up numbers

You want 30 purchases per variant, cost per purchase is about 25 and you test 3 variants. Budget = 30 x 25 x 3 = 2,250.

Keep the test small enough

Test one change at a time, and limit variants to what the budget supports.
If you cannot afford the budget, test a cheaper step such as hook rate, and say so.

Stop rules

Write the stop rule and the verdict rule before launch, as numbers.
Do not extend a test because you dislike the result.

6 min read. Last updated 2026-10-07. Examples use made-up numbers.

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Decide how many results per variant you need before you would trust a difference. Fewer variants need less budget.
Estimate cost per result from recent data for the same audience.
Budget per variant = results needed x cost per result.

Terms in this guide

CPA Hook rate Creative ID

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