Small business marketing budget: how much, and where to put it

Aug 18
3 min read

Updated: Aug 27

Introduction

The usual advice is to spend some percentage of revenue on marketing. It is memorable and close to useless, because it takes no account of your margins, your customer lifetime value, or what you are trying to fix.

A budget derived from your own numbers is both more defensible and usually different from what the percentage rule suggests.

1. Build a small business marketing budget from unit economics

Start at the other end. Rather than asking what you can afford, ask what a customer is worth.

Work out the gross profit an average customer produces over their whole relationship. Divide by three to get a sensible maximum acquisition cost — that leaves room for overheads and for your estimate being optimistic.

Now multiply by how many additional customers you want. That is your acquisition budget, and it is tied to something real.

If a customer produces $240 in gross profit, your working ceiling is around $80, and thirty additional customers means roughly $2,400. That figure has a rationale behind it.

2. Separate build from spend

Two categories that behave completely differently and should never share a line.

Build is one-off work that creates something durable: measurement, tracking, a pricing structure, a loyalty mechanic, documented procedures. It has an end and it leaves an asset.

Spend is ongoing: media, tools, production. It buys results while it runs and stops when it stops.

Businesses that budget only for spend never accumulate anything. Businesses that budget only for build have machinery and nothing running through it.

3. Fund the build first, once

If you are starting from little, the first allocation should be the measurement layer.

It is the cheapest component and it makes every subsequent decision informed rather than guessed. Without it you cannot calculate acquisition cost or lifetime value, which means you cannot set a budget from unit economics at all — you are back to the percentage rule.

Spend on measurement before spend on media. It feels like a delay and it is the opposite.

4. What percentage rules get wrong

The reason they mislead is that they ignore margin.

A business at 60% gross margin can afford several times the acquisition cost of one at 20%, on identical revenue. A percentage-of-revenue rule treats them the same and will overspend one and starve the other.

They also ignore where you are. A business fixing retention needs almost no media budget and some build budget. A business with excellent retention and no visibility needs the reverse.

5. Do not split a small budget across many channels

The most common allocation mistake. Four channels at a quarter each means none accumulates enough data to optimise, and you finish the quarter knowing nothing about any of them.

Concentrate on the one that matches your situation, run it long enough to gather real conversion data, and get cost per customer below what a customer is worth. Add a second channel only once the first is working and funded.

Sequential beats parallel when the constraint is information rather than money.

6. Hold a testing reserve

Set aside a modest portion — a tenth or so — for things you have not tried, and treat it as research rather than performance.

Judge it on what you learned, not on return. A test that establishes a channel does not work has done its job, and doing that cheaply is the point.

Without a reserve, businesses either never test or test with money they needed, and both are worse.

7. Review it against results, quarterly

A budget set annually and left alone stops matching reality within a quarter.

Review it against actual acquisition cost and lifetime value. If acquisition cost is comfortably below the ceiling, increase the budget — you are buying profit. If it is above, the answer is not more money but fixing conversion or the offer.

That is the loop that makes a budget a decision rather than a guess.

Conclusion

Set the budget from what a customer is worth rather than from a percentage of revenue: gross profit per customer, divided by three, multiplied by the customers you want.

Separate build from spend, fund the measurement first, concentrate rather than splitting, hold a small testing reserve, and review quarterly against actual results. A budget derived this way tells you when to spend more — which a percentage rule never can.