Every parts system you have ever been shown was built for somebody bigger than you.
It opens on a catalogue you are expected to build. It wants bin locations for racking you do not have, reorder points for stock you do not hold, and a stock take you will never do because there is nothing on the shelf to count except oil, filters and a box of bulbs. Ten minutes in, you close the tab and reach the entirely correct conclusion: this is more system than my workshop needs.
So the margin stays where it has always been. On the invoice the pads were £89. What they cost is on a factor invoice in a drawer, or in an email, or in the bank statement at the end of the month mixed in with forty others. You know parts make you money. You could not tell anyone how much.
This post is about the small version of parts, the one that fits a workshop that buys almost everything per job. It is two extra fields on a line you are already typing.
What most workshops actually do
The pattern is the same across two ramps or six. A car comes in, the technician finds the fault, the advisor rings the factor, the part is on the van by eleven. Somebody types "front brake pads" onto the job card with a price on it, the customer pays, the job closes.
Nothing in that sequence is wrong. It is fast, it works, and it is why independents can turn a job around in a morning when a franchise cannot. The only thing missing is the left-hand side of the sum. You recorded what you sold it for. You did not record what it cost you.
And because you did not record it, the number cannot exist later. Not on that job, not on that month, not on that customer. You are running a business where one of the two revenue streams has no cost attached to it.
Two fields
Here is the entire ask, on a workshop parts system that does not require you to hold stock.
When your advisor types a part onto a job card line, they fill in two more boxes: what it cost and who it came from. There is a third box for the supplier's invoice reference if you want it, and it is worth thirty seconds when a query comes back three months later.
That is it. No catalogue. No part record created. No stock level to maintain, no bin to assign, nothing to count. The line behaves exactly as a typed line always has, plus the cost.
What you get back is the sum:
BP-1147 front brake pads. Cost £41.20 from your factor, invoice 88213. Sold at £89.00. Gross profit £47.80, 53.7%.
On that job. On that invoice. In that month's numbers, as a parts figure separate from labour.
A quick note on what gross profit means here, because an accountant will ask. It is what you sold the part for minus the cost you recorded on the line. It does not carry carriage, it does not carry labour, and it does not carry any share of your overhead. It is the parts margin on that part, which is precisely the number nobody currently has.
Why the cost has to go on the line, not in the accounts
The obvious objection is that the cost is already captured. The factor invoice goes to the bookkeeper, it ends up in Xero, the accountant sees parts purchases at year end.
True, and useless for this. Your accounts know you spent £4,180 with a factor in March. They do not know which of those parts went on which job, what each was sold for, or which jobs made money on parts and which quietly did not. Cost and revenue are both recorded and they never meet.
That is the whole trick, and it is not a sophisticated one. The margin only exists at the point where what you paid and what you charged sit on the same line. Everything else in a parts module, the catalogue and the stock and the purchase orders, is machinery for workshops that need it. The margin does not need any of it.
What you find out
Dealers who start recording cost on the line tend to discover three things in the first month, and rarely the ones they expected.
A few jobs have almost no parts margin at all. Usually the ones where the part was priced by memory, from what it cost the last time, before the price moved. See stop pricing parts in your head for the fix.
One supplier is quietly more expensive than the others. Not across the board, which you would have noticed. On one category, where you always ring them first out of habit.
Parts are a bigger share of the month than assumed. Most workshop owners run on the labour figure because clocked hours force it to exist. The parts figure has been invisible, not small. We pulled that argument apart in your labour figure is honest, your parts figure is a guess.
When you outgrow two fields
The point of starting small is that nothing has to be decided up front.
If you do hold a shelf of consumables, or you start to, the rest is already there waiting: a catalogue you can import from a CSV with a dry run that tells you which rows it cannot read before anything is created, stock levels per branch, where each part lives on the shelf, reorder points, purchase orders to your suppliers, and deliveries booked in against the job that was waiting.
You switch those on when the workshop needs them. Plenty of dealers never will, and the two fields will still be earning their keep years later.
What this is not
Worth saying plainly, because parts software means different things in different corners of the trade.
This is a workshop parts department, built around the job card. It is not a trade counter. There is no customer-facing parts sale, no parts e-commerce, and no over-the-counter till. If you are a motor factor or a standalone parts retailer, this is not the tool for you and we would rather say so now.
It also does not plug into your factor's catalogue. The parts are yours, either typed on the job or in a catalogue you loaded. There is no live price lookup into a supplier's system.
Where to start
If you buy per job and hold nothing, do this: for the next two weeks, fill in the cost and the supplier on every parts line. Nothing else. At the end of the fortnight look at the parts gross profit figure and decide whether it was what you thought.
That is the whole experiment, and it costs you about four seconds a line.
Parts is part of Vehiso Workshop at no extra cost. It is not available on the Free plan, since Workshop itself is not.
