Unbilled Work: How Much Is Your Trade Business Giving Away?

Ask most tradespeople what costs them money and you'll hear about materials going up, fuel, the van, the customer who still hasn't paid from March. Those are real. But there's another one that rarely gets mentioned, because nobody notices it happening.

It's the work that gets done and never makes it onto an invoice.

It's rarely the big jobs. It's the small ones: extras, second visits, the part taken from the van. None of them feels like a loss at the time, because no money goes out. The money just never comes in. We run an installation business in Horsham ourselves, so this is written from the van, not the boardroom.

Why Unbilled Work Hurts More Than It Looks

When a customer pays late, you still get the money eventually. When a job never gets invoiced, you've already paid for the labour, the fuel and usually the parts. Every pound you didn't bill is a pound straight off your profit.

That's what makes it expensive. Here's a simple illustration, with round numbers so you can check them. Say your business keeps 25p in every pound as profit after all its costs. To replace £240 of work you forgot to invoice, you'd need to win and do roughly £960 of new work (£240 ÷ 0.25). Forgetting one small job can undo the profit on four.

Where It Hides

Unbilled work tends to come from the same handful of places, whatever your trade.

The "while you're here" extra

You're fitting a new tap and the customer asks if you could look at the one in the cloakroom. Twenty minutes and a washer later, it's sorted. You meant to add it to the invoice. By the time you write it up that evening, it's gone from your head, or it feels awkward to charge for something so small.

Changes agreed on site

The customer decides halfway through that they'd like the socket moved, or a better valve, or one more radiator. You agree on the spot, by word of mouth. The original quote is what ends up on the invoice, because that's the only thing written down.

Parts from the van

Fittings, clips, a length of pipe, a fused spur. Taken from van stock, used, never recorded. Each one is small. Across a year of jobs they add up to a stock bill you paid and never passed on.

The Friday job

A job finishes late on a Friday. You'll invoice it on Monday. On Monday there's an emergency, and by Wednesday it's slid down the list. Some of these get found weeks later. Some never do.

The second visit

You go back because a part was on order, or because the customer wasn't in, or because something genuinely needed another look. Sometimes that visit was included. Sometimes it should have been charged, and nobody decided which.

The balance after a deposit

For bigger jobs you take a deposit. The deposit invoice goes out promptly because you need it to order parts. The balance invoice relies on someone remembering to raise it when the job is done, which is exactly when everyone's attention has moved to the next job.

How to Work Out Your Own Number

You don't need software for this. You need an hour, a cup of tea and your records for the last three months.

1. List every visit. From your diary, calendar, WhatsApp, the back of the van book, wherever it lives. Every time you or your team went to a customer.
2. Match each visit to an invoice. Put a tick next to every visit that appears on an invoice somewhere. Be strict: a visit that was "included" should be included on purpose, not by accident.
3. Look at the gaps. For each visit with no tick, ask: was this genuinely free (a warranty callback, a goodwill visit), or should it have been charged?
4. Check deposits. For every deposit invoice, is there a matching balance invoice?
5. Compare materials. Roughly, does what you bought from the merchant line up with what you charged customers for materials? A big gap suggests van stock walking out unbilled.

Then do the sum. Here's an example with made-up but realistic figures, not data from any real business. A small heating firm does about 60 jobs a month with an average invoice of £240. If one job a month slips through, that's 1 × £240 × 12 = £2,880 a year, all of it margin. If it's one a fortnight, it's nearer £6,240 (26 × £240).

Your number might be lower than that. It might be higher. The point is that most firms have never looked, and the only way to know is to check.

Habits That Stop It

Most of the fixes aren't clever. They just move the paperwork closer to the moment the work happens.

Invoice before you leave the drive

The single biggest improvement for most small firms. If you can raise the invoice on your phone while you're still outside the house, the job is fresh in your mind and the extras are still on your hands. It also tends to get you paid sooner, because the customer is looking at it while the work is in front of them.

Write changes down, even briefly

When a customer asks for something extra, send a one-line text: "Happy to move that socket, it'll be £65 on top of the quote." It takes ten seconds. It gives the customer a clear choice, it saves an awkward conversation at the end, and it gives you something to copy onto the invoice.

Decide your small-jobs rule in advance

A lot of unbilled work is really unpriced work: you didn't charge because you hadn't decided whether to. Pick a rule and stick to it. A minimum charge for any visit, a set price for common extras, or a clear "the first ten minutes are on us" policy. Customers are generally fine with whatever the rule is, as long as it's consistent and you tell them up front.

Raise the balance invoice when you book the job

If you take deposits, create the balance invoice as a draft at the same time as the deposit. Then the question at the end of the job isn't "did I remember?" but "is it right?".

One list, checked weekly

Keep a single list of "finished, not invoiced", and look at it at the same time every week. Friday afternoon works for a lot of people. If nothing's on it, it takes thirty seconds. If something is, you've caught it within days, not months.

Where Software Helps (and Where It Doesn't)

No system will invoice for a conversation it never heard about. If the extra was agreed over the fence and nobody wrote it down, software can't save you. The habits above matter more than any tool.

What software can do is keep that "finished, not invoiced" list for you, so it doesn't depend on anyone's memory. Any decent job management system that links jobs to invoices should be able to show you jobs marked complete with no invoice against them. It's worth asking that question of whatever you use now.

It's one of the reasons we built HomeHub Office, the system we use to run our own installs. Its review page lists every job marked finished with no invoice sent, every accepted quote that never became a job, and every invoice left sitting in draft, with the amount at stake next to each one. If you'd like to see the numbers behind this article worked through in more detail, there's a worked example and a calculator you can use with your own figures.

Whatever you use, do the three-month check. It's an uncomfortable hour for most of us, but it's usually the best-paid hour of the month.

And if part of the problem is customers who are slow to pay once the invoice does go out, we've written about that too: chasing quotes and invoices without being awkward.