Guide

Your marketing budget, set by the gap in your schedule

Skip the generic "spend 7-10% of revenue" advice. Here's a formula that sets your marketing budget from the actual gap in next month's schedule, with a worked example and three spending states depending on how booked you are.

Why the 7-10% rule doesn't fit an owner-operator

The 7-10% of revenue rule comes from corporate marketing budgets, where the job is brand-building across a whole year. It assumes a marketing department, a sales funnel and a business that needs to grow every quarter regardless of capacity.

You don't have that problem. You have a fixed number of hours in the week. Some weeks they're all booked. Some weeks they're not. Spending a flat percentage of revenue makes no sense when the real question is simpler: how many hours am I short next month, and what will it cost me to fill them?

A plumber turning revenue over £150,000 a year on the 8% rule would spend £12,000 on marketing whether he's booked solid for six weeks or has three empty days next week. That's not a budget, it's a guess dressed up as a formula.

The formula: budget from unbooked hours, not from revenue

Here's the actual calculation:

Budget = (unbooked billable hours next month × hourly rate × target fill rate) × acceptable acquisition cost %

Each part matters:

• Unbooked billable hours — look at next month's schedule right now. Count the hours you could fill but haven't. Not total hours in the month, just the gap.
• Hourly rate — your real billable rate, not your day rate divided by 8. If you haven't worked this out properly, run it through the hourly rate calculator first, because everything downstream depends on it being right.
• Target fill rate — you won't fill every gap. 70% is a realistic target for most trades chasing new work; be more conservative if your close rate on leads is weak.
• Acceptable acquisition cost % — the share of that revenue you're willing to spend to win it. This is the lever you control, and it should move with how desperate the gap is.

Worked example

Take an electrician with 40 unbooked billable hours in next month's diary, billing £95/hour, aiming for a 70% fill rate.

Step	Calculation	Result
Revenue at stake	40 hrs × £95/hr × 70%	£2,660
Acquisition ceiling	15% of £2,660	£400 (approx)

That's the whole answer: £400, not £1,500. A flat 8% of, say, £15,000 monthly revenue would have suggested £1,200 — nearly three times what the actual gap justifies. The gap-based number is smaller because it's tied to real hours you need to fill, not to money you've already earned elsewhere.

Run this against last month's actual jobs through the job profitability calculator to sanity-check that £95/hour is what you're really clearing after materials and callback time, not just what you invoice.

The acquisition ceiling depends on how full you are

The percentage you apply isn't fixed. It should scale with urgency. Three states cover most weeks:

State 1: booked 3+ weeks out — 2-3%

You're not short of work, you're short of nothing. Spend goes on keeping the pipeline warm for later, not filling anything now: a referral thank-you scheme, asking happy customers for reviews, a occasional post showing recent jobs. This is reputation maintenance, not lead generation. Anything more is money you can't justify against an empty slot that doesn't exist.

State 2: booked 1-2 weeks out — 5-8%

There's a real but modest gap forming. This is the zone for steady, repeatable channels: Google Business Profile upkeep, a boosted post to a local area, retargeting past customers who haven't booked in a while. Nothing urgent, nothing expensive per lead. You're topping up, not scrambling.

State 3: gaps next week — 10-15%

This is the worked example above. You need bookings fast, so the money goes into the fastest-converting channel you have, usually paid search on high-intent terms, or a same-week promotion to your existing list. Don't spread this across five channels to "test" — you don't have time to test, you have hours to fill by Friday. Put it where you already know leads convert.

Schedule state	Acquisition ceiling	Where the money goes
Booked 3+ weeks	2-3%	Referrals, reviews, reputation only
Booked 1-2 weeks	5-8%	Steady low-cost channels, GBP, retargeting
Gaps next week	10-15%	Fastest-converting paid channel

The floor nobody should go below when full

Even in State 1, don't drop to zero. A business with a full diary and no marketing spend at all is one slow month away from a crisis, because reputation channels take weeks to produce a booking, and you won't start them in time once the gap appears. Keep a minimum spend running at all times, even if it's just the cost of a review-request tool and an hour a month asking for referrals. Treat that floor as a fixed cost, the same way you'd treat insurance: cheap while you don't need it, expensive to have skipped when you do.

Check the number against your break-even point

Before you commit any acquisition budget, check it doesn't push you below what the business actually needs to survive the month. Run your fixed costs through the break-even calculator so you know the minimum billable hours you need regardless of marketing spend. A gap-based marketing budget only works if the gap itself is realistic, don't chase hours you can't afford to leave unbilled while you wait for the campaign to convert.

Putting it together each month

This isn't a one-off calculation, it's a five-minute check you run at the start of every month:

1. Count unbooked billable hours in the coming month's diary.
2. Multiply by your real hourly rate and a realistic fill target.
3. Pick the acquisition ceiling that matches how booked you are.
4. Spend that number, in the fastest-converting channel your urgency demands.
5. Never let spend drop below the reputation floor, even when fully booked.

The result moves with your actual schedule instead of your last quarter's revenue. Some months it will be £400. Some months it will be £4,000. That's the point, the budget follows the gap, not a fixed percentage that has no idea whether you're busy or not.