You’ve finished the job. Customer’s paid. Boiler’s running sweet.
Job done, right?
But here’s the question most plumbers never ask: Did I actually make any money on that job?
Not “did I get paid,” that’s a given. I mean after materials, after labour, after all the bits you forgot to charge for, what was actually left in your pocket?
If you can’t answer that, you’re guessing. And when you’re guessing, you’re losing money on jobs you think are winners.
Let me show you how to work it out properly.
Start With Your Original Quote
Pull up what you quoted the customer.
What did you say it would cost?
- Labour: How many hours did you quote? Just you or did you need a mate?
- Materials: Radiators, pipes, fittings, boiler parts, valves, whatever you listed
- Total price
Write it down. That’s your starting point.
Now Work Out What It Actually Cost
This is the bit most plumbers skip. And that’s why they’ve no clue if they made money or not.
Here’s what you actually need to count:
Labour costs:
- How long did the job actually take?
- Did you quote 4 hours and it took 6 because the pipework was a nightmare?
- Did you need your mate for half a day you didn’t plan for?
- Did you have to come back the next day because you were waiting on a part?
Take the actual hours and multiply by your hourly rate. If you’re charging yourself out at £45/hour and your mate’s £15/hour, add it all up.
Materials costs:
- What did you actually spend at the merchant?
- Not what you estimated. What the invoices say.
- Did you have to make two trips because you forgot the compression fittings?
- Did you use something from the van you already paid for? (Still counts.)
Pull your invoices. Total it up.
Parts you didn’t charge for:
- Customer said “the tap’s dripping, can you have a quick look?”
- You replace a washer. Takes 10 minutes. You don’t charge them.
- Or you fit an extra isolator because “it should’ve been there anyway.”
That’s still your time and your materials. Cost it.
Other stuff people forget:
- Fuel. You drove 40 minutes each way. That’s not free.
- Parking if you had to pay for it.
- Van costs, insurance, tools (yes, these add up).
- That emergency call-out on Saturday you had to squeeze in.
Do The Maths
Right, now you’ve got your two numbers.
What you charged: £850
What it actually cost:
- Labour: 6 hours @ £45/hour = £270
- Mate’s time: 3 hours @ £15/hour = £45
- Materials: £280 (actual invoices)
- Extra bits you didn’t charge: £40 (tap washer, isolator valve)
- Fuel and other: £35
Total cost: £670
Profit: £850 – £670 = £180
£180 for 6 hours work. That’s £30/hour.
Better than minimum wage, but is that what you thought you were making?
And you thought this was a decent job because the customer didn’t complain about the price.
What This Tells You
Once you’ve done this for 5 or 10 jobs, you start seeing patterns.
Jobs always take longer than quoted? You’re underestimating how long things actually take. Your quotes are wrong.
Materials always cost more than you thought? You’re either guessing at the merchant or you’re not tracking what you’ve already got in the van.
You’re always throwing in extras? The “quick look” at the leaking tap or the “I’ll just fix that while I’m here” is costing you hundreds a month.
Certain jobs never make money? Small repairs, call-outs, “quick fixes” if they’re not clearing you at least £40-50/hour after costs, why are you doing them?
Why Plumbers Don’t Track This
Because it’s depressing.
You don’t want to find out that the boiler service you thought made you £200 actually made you £60 after you factor in the time, the parts, and the return trip because you needed a different flue adaptor.
But if you don’t know, you’ll keep making the same mistakes.
You’ll keep quoting too low. Keep doing freebies. Keep working 50-hour weeks and wondering why you’re skint.
The Jobs That Kill You
Here’s what I see all the time with plumbers:
The “while you’re here” jobs: Customer books you for a radiator replacement. While you’re there: “The kitchen tap’s dripping, can you look?” Then it’s “the shower’s losing pressure.” Before you know it, you’ve been there an extra 90 minutes and you’ve charged them nothing.
The emergency call-outs: Saturday afternoon. Burst pipe. You drop everything, drive 30 minutes, fix it in an hour. You charge £180. Feels decent. But you’ve just worked 2.5 hours (drive, fix, drive back), used £25 in parts, and burned your Saturday. After costs, you cleared £80. For a Saturday.
The “I’ll just do it properly” jobs: You’re fitting a new tap. Customer’s isolation valves are knackered. You know if you don’t replace them, you’ll be back in 6 months. So you do it. Don’t charge. Cost you £30 in parts and 20 minutes. Times 10 jobs a month, that’s £300 you’re giving away.
What To Do Next
After every job, spend 5 minutes.
Write down:
- What you quoted vs what it actually cost
- How long it really took
- What you did that wasn’t on the quote
Do this for a month. You’ll see exactly where your profit’s disappearing.
Then fix it.
Most plumbers are working twice as hard as they need to because they’ve no idea what jobs actually make them money.
Stop being one of them.
Need help working out where your money’s going? That’s what we do at Trade CS. We help UK trade businesses find the profit drains, fix them, and build systems that keep you profitable. Drop us a message.
