You negotiate your prices, you watch your food cost, you count your stock. Meanwhile an invoice arrives with a price that is not the agreed one, a quantity that is not what was delivered, or a line nobody ordered. It gets paid. Nobody saw it.
Checking supplier invoices is one of the few areas where you recover margin without selling anything more and without renegotiating anything. Here is how to go about it.
Why it is a blind spot
Three reasons stack up, and they are structural.
The invoice arrives after the fact. It is matched against a delivery days, sometimes weeks later. By then nobody remembers whether the 12 kg stated were really 12 kg in the box.
Whoever receives is not whoever pays. In the kitchen, people check freshness and temperature, rarely unit prices. In the office, someone sees a total that looks like the previous totals.
The gap is always small. Nobody disputes €4 on a €380 invoice. But €4 per invoice, across four deliveries a week and ten suppliers, becomes a budget line.
That is exactly the profile of a lasting loss: too small to trigger an alarm, too regular to be negligible.
The principle: match three documents
A serious check does not compare two documents, but three:
| Document | What it states |
|---|---|
| The purchase order | What you asked for, and at what price |
| The delivery note | What actually arrived |
| The invoice | What you are being asked to pay |
This is three-way matching. Comparing only invoice to delivery note verifies quantities but lets price drift through. Comparing only invoice to order verifies prices but cannot see what was missing from the box.
Both checks are needed, and they catch different things.
The five most common discrepancies
1. The price that is not the negotiated one
The most frequent, and the costliest over time. A rate was agreed, an increase is applied without notice, or the old price reappears on a promotional reference. The gap is often a few cents per unit.
It is the easiest one to catch — provided the reference price is in front of you when you check.
2. Quantity invoiced higher than quantity received
A missing case, an item rejected on delivery for non-conformity, an incomplete pallet. The invoice, meanwhile, simply repeats the original order.
This case assumes you have recorded the actual receipt, not just waved the delivery through.
3. The line nobody ordered
A substitute product sent without agreement, an item added by mistake, a backorder from a previous delivery billed twice. It appears on no purchase order.
4. The pack-size change
The subtlest trap. The price per case has not moved, but the case went from 6 × 1 kg to 6 × 800 g. The price per kilo rose by 25% without any displayed price changing.
A check that only looks line by line sees nothing. Only the price brought back to the unit of use reveals it.
5. Ancillary charges
Delivery fees billed although free-delivery threshold was met, small-order charges, fuel surcharges. Legitimate or not, they must at least be seen — and related to the cost of the goods they come with.
The method, in practice
Checking every line of every invoice is not realistic. Here is a workable setup.
1. Record the receipt as it arrives. This is the piece that is almost always missing. Without the quantity actually received, no matching is possible — you can only compare the invoice to itself.
2. Systematically check your high-value families. Meat, fish, spirits: they concentrate the value, therefore the risk. The rest can be spot-checked.
3. Look at the price per unit of use, not per case. It is the only way to see pack-size changes.
4. Set an explicit tolerance threshold. Below it, let it go; above it, dispute. Without a threshold, you dispute everything for a month and then nothing.
5. Keep a record of what you disputed. A supplier who knows you check makes fewer mistakes. That may be the real benefit of the whole exercise.
What to do when a discrepancy appears
Do not pay while you work it out, and do not block the whole invoice over one line either.
The usual approach: report the discrepancy in writing, quoting the purchase order and delivery note numbers, and ask for a credit note rather than a refund — it is simpler for everyone and offsets against the next invoice.
Bear in mind that most discrepancies are not deliberate: a data entry error, a rate not updated in the supplier’s system, a substitution decided by the picker. A factual tone gets a credit note far faster than an accusing one — and preserves a relationship you need.
What it actually represents
Let us run the numbers for a venue buying €200,000 a year.
Average undetected discrepancy : 1% of purchases
1% × €200,000 = €2,000 / yearOne point of discrepancy is €2,000 leaving with nothing in return. For a restaurant whose net result is counted in tens of thousands, that is not an accounting detail.
And unlike a supplier renegotiation, this gain is not up for discussion: it is yours by right, you only have to claim it.
There is a second, less visible but longer-lasting effect: as long as invoiced prices do not flow back into your costs, your food cost is wrong. You steer on theoretical purchase prices while paying the real ones. That is the subject of our article on calculating food cost — a ratio is only worth as much as the prices feeding it.
The other cost: time spent
We always talk about the money recovered. We forget that checking has a price of its own, and that this price decides whether it happens at all.
Take an ordinary invoice. Keying it into your management tool takes three to five minutes depending on the number of lines. Matching it against the order and the delivery note takes as long again. Call it six minutes per invoice, which is optimistic as soon as you have to find the delivery note in a pile.
40 invoices / month × 6 min = 4 h / month
4 h × 12 = 48 h / year
48 h × €22/h fully loaded ≈ €1,050 / yearA working week a year, for a mid-sized venue. And this time has a particularity: it is almost always absorbed by the owner, outside service hours. On Sundays, in the evening, between two rushes.
That explains the scenario you see everywhere: the check is set up diligently in January, held for three weeks, then dropped. Not through negligence, but because a routine costing half a day a month does not survive a busy month.
A check you have no time to run returns nothing. Which is why the time question is not secondary to the margin question: it governs it. The €2,000 of discrepancies above are only recovered if somebody looks, every month, without giving up their evening.
Our article on the ROI of food cost software breaks down this double lever — margin on one side, time on the other — and how to put figures on both using your own data.
Automating what can be automated
Done by hand, this check is sound: it is simply too costly in time to last. Keying an invoice takes minutes, matching it takes as many — and that is precisely why checking ends up being skipped.
This is exactly what FoodCostOS’s supplier invoice scanning automates: the invoice is read from a photo or a PDF, automatically matched against what you ordered and received, and discrepancies are flagged before you confirm. The prices read then update your purchase costs, so your margins reflect what you actually paid.
The checking stays yours. What disappears is the keying.
Frequently asked questions
Do I need to check every invoice?
No, and trying to check everything is the surest way to check nothing. Focus on your high-value families and on suppliers where discrepancies have already shown up. The rest can be spot-checked, a few invoices a month.
What tolerance threshold should I set?
There is no standard. Many venues use an absolute threshold (a few euros, say) alongside a percentage threshold on the line. What matters is that it is written down and known by whoever checks, otherwise each case is decided on the spot and the routine erodes.
Can a supplier refuse a credit note?
They can dispute it, rarely refuse it when the discrepancy is documented. This is where the signed delivery note matters: it is your evidence. Without a record of what was actually received, the discussion comes down to your word against theirs.
Can one invoice cover several deliveries?
Yes, commonly so with suppliers who deliver several times a week and bill fortnightly or monthly. Matching must then be done delivery by delivery, not on the total — a correct total can perfectly well hide two discrepancies that cancel each other out.
How long should supplier invoices be kept?
Retention is set by your local accounting and tax rules — ten years in France, six in the UK, and it varies elsewhere. Digital archiving is generally accepted under conditions; check the specifics with your accountant.
Where do I start if I check nothing today?
Take your three main suppliers and one month of invoices. Match them against your orders. Within half a day you will know whether you have a problem, and with whom — which beats building a full routine only to discover it finds nothing.