The minimum budget to test an advertising channel properly

Key takeaways

The minimum advertising budget for a fair test is the smallest sum that can produce about 20 enquiries, or at least six weeks of exposure. Below that, you are buying an anecdote. Social media has the lowest floor, which is why it is the usual place to start.

• Paid social: £300–£500 a month for two months.
• Leaflets: two drops to one area, about £600 to £1,500.
• Local print: three insertions, about £450 to £3,000.
• Local radio: three weeks, several thousand pounds.

What makes a test fair?

A fair test gives a channel enough exposure to work and enough responses to read. One advert shown once tests your luck. As a working rule, aim for about 20 tracked enquiries or six to eight weeks, whichever comes later, with the same offer throughout.

• Social media marketing vs traditional advertising: what works better for SMEs?
• How to test an advertising channel in six weeks

What is the minimum for social media?

For paid social, a practical floor is £300–£500 a month in advertising spend for two months. Platforms accept far smaller daily budgets, but very low spend reaches too few people to learn from. Unpaid posting needs no media budget and about three months of steady effort.

• Paid social budgets for UK small businesses
• Facebook ads versus boosted posts

What is the minimum for traditional media?

Traditional media need enough repetition to be noticed, which raises the floor. Using indicative UK ranges, these are sensible minimums.

• Leaflets: two drops to 5,000 homes, £600 to £1,500.
• Local newspaper or magazine: three insertions.
• Local radio: three weeks of airtime plus production.
• Outdoor: one well-placed site for four weeks.
• Direct mail: 300 to 500 letters to a chosen list.

• How much does advertising cost a UK small business?
• Advertising frequency: how many times must people see an ad?

Why do small tests give wrong answers?

Small tests give wrong answers because chance dominates. If a £100 advert brings two calls, was that the advert or the weather? One more or one fewer call would halve or double the result. Too small a test usually ends with a good channel being written off.

• Cost per lead by channel: comparing social media and offline

How do you size a test from your own numbers?

Work backwards from the enquiries you need. If you expect to pay about £25 an enquiry and want 20 to judge, budget £500. If you have no idea of the cost per enquiry, run the cheapest channel first to get one, then use it as a yardstick for the others.

• 1. Estimate cost per enquiry.
• 2. Multiply by 20.
• 3. Add production and time.
• 4. Check you can afford to lose the total.

What if you cannot afford the minimum?

If you cannot afford the minimum for a channel, do not buy a smaller version of it. Choose a cheaper channel and test that properly. A full test of social media teaches more than a third of a radio campaign.

• Free advertising for small businesses: 12 ways that work
• Choosing social media platforms with no budget

Is there a maximum for a test?

Yes: never test with money you cannot afford to lose. A common working rule is to keep about 10% of the advertising budget for tests, with the rest behind channels that already pay. A test is finished when it has answered its question, not when the money runs out.

• How to split a marketing budget between traditional and digital
• The advertising channel scorecard: pick where to spend

What does this look like in practice?

A pattern we see with cautious first-time advertisers: £50 is spent on a boosted post, nothing obvious happens, and paid social is dismissed for a year. The channel was never tested. It was sampled at a size that could not have shown anything either way.

• See client work
• Social Media Marketing for UK businesses

Checklist before starting a test

• One channel, one area, one offer.
• A budget large enough for about 20 enquiries.
• A tracking method in place before day one.
• A fixed end date and a decision rule.
• Money you can afford to lose.

Next step

Pick the channel you are most curious about and write down the smallest budget that could bring 20 enquiries. If you cannot afford it, pick a cheaper channel.