Ad budget calculator
The useful question is not how much to spend but how to split it. This calculator divides a monthly budget between testing and scaling, then converts the testing share into the number of variations it can actually resolve, which is the constraint most plans ignore.
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The formula
Testing budget = monthly budget x testing share
Variations resolvable = (testing budget / CPM) x 1,000 / 2,000
Twenty percent to testing is the common convention and it is a starting point rather than a law. What makes it right or wrong is the second line: if the testing share cannot deliver about 2,000 impressions to each variation in a set, the test is unresolvable and the money is spent learning nothing.
How to read the result
- The production row is usually the surprise. Filling a month of test slots costs a small fraction of the media needed to read them, which is the argument for testing more rather than for producing less.
- If resolvable variations comes back under 8, shrink the set rather than the budget. Fewer, larger changes are readable at low spend; twelve small ones are not.
- Scaling budget should sit behind proven creative only. Money spent scaling an untested ad is testing at scaling prices.
What people get wrong
- Allocating a testing percentage without checking it can resolve a set.
- Counting production as the expensive half. At about €1.52 a variation it is rarely more than a few percent of the media.
- Running a testing budget with no separate scaling budget, so every winner immediately competes with its own successors.
- Leaving the split fixed as spend grows. A larger budget against the same audience needs a larger share going to creative, not a smaller one.
Frequently asked questions
How much of my ad budget should go to creative testing?
Twenty percent is a reasonable default, but the binding test is whether that share delivers about 2,000 impressions to each variation you want to read. If it cannot, either raise the share or test fewer variations.
How do I know if my testing budget is big enough?
Divide it by your CPM, multiply by 1,000, and divide by 2,000. If the answer is under 8 you cannot resolve a normal creative set.
Does production cost change the split?
Less than people expect. At about €1.52 per variation, filling a month of test slots is typically a few percent of the media budget needed to read them.