Three-way matching compares three documents before a supplier invoice is approved for payment: the purchase order (what you agreed to buy), the goods receipt (what physically arrived) and the invoice (what you are being billed). When all three agree within tolerance, the invoice is cleared. When they disagree, the mismatch is held for a human to resolve.
Three-way matching is one of the oldest controls in business, and it survives because it answers a question every operation eventually gets wrong: are we about to pay for something we never received?
For a distributor buying the same catalogue items every week, the control is close to mechanical. For a make-to-order manufacturer it is not. Almost nothing you buy is a catalogue item, quantities change mid-order, suppliers ship in pieces, and the person who knows whether the goods were right is on the shop floor rather than in accounts payable.
The three documents
Matching compares three records that are created at three different moments by three different people.
| Document | Created by | Answers |
|---|---|---|
| Purchase order | Purchasing, at the point of commitment | What did we agree to buy, at what price, on what terms? |
| Goods receipt | Receiving, when the truck arrives | What physically turned up, in what quantity and condition? |
| Supplier invoice | The supplier, on their own schedule | What are we being asked to pay for? |
The three records provide independent evidence when responsibilities and permissions are separated. Matching helps reveal differences, but it does not itself prevent one person from controlling every step. Approval rights and review responsibilities must support the document check.
Why make-to-order is harder
The textbook version of matching assumes stable items, stable prices and complete deliveries. Make-to-order breaks all three assumptions.
- The item is unique to the job. You are not buying part number 4471, you are buying a fabricated bracket to a drawing. There is no catalogue price to match against, only the quoted price on that specific purchase order.
- The specification changes after the order is placed. A customer change order alters a dimension, purchasing revises the supplier order, and the invoice arrives priced against a revision nobody in finance has seen.
- Deliveries arrive in pieces. Four of six units ship this week, the balance in three weeks, and the supplier invoices each shipment separately.
- Ancillary charges arrive detached. Freight, crating, expedite fees and finishing charges land on the invoice without ever appearing on the original purchase order.
- Receiving is not a warehouse function. The material may be delivered straight to a bay, checked by the person who will install it, and never touched by anyone whose job is inventory.
Each of these turns a clean three-way match into an exception. Operations that run matching on paper usually respond by abandoning the control for anything awkward — which is precisely the population of purchases where errors are most likely and most expensive.
A worked example
A shop orders six fabricated frames at $420 each for a specific job, with $180 of freight expected.
| Event | Qty | Unit | Value | Match state |
|---|---|---|---|---|
| Purchase order raised | 6 | $420.00 | $2,520.00 | Committed |
| Receipt 1 — partial delivery | 4 | $420.00 | $1,680.00 | Received, unbilled |
| Invoice 1 — 4 frames + freight | 4 | $420.00 | $1,785.00 | Matched, freight to apportion |
| Receipt 2 — balance | 2 | $420.00 | $840.00 | Received, unbilled |
| Invoice 2 — 2 frames, revised price | 2 | $447.00 | $894.00 | Held — price variance |
| Total invoiced | 6 | — | $2,679.00 | vs $2,700 expected |
Under the example policy, Invoice 1 can proceed after the $105 freight charge has been accepted and its treatment agreed: quantity and item price match. Invoice 2 needs review because its unit price is approximately 6.4% above the order. These are illustrative outcomes, not a claim that every system automatically applies this policy.
The important detail is what the exception is. It is not necessarily an error. The supplier may have quoted a revised price against a change order that purchasing accepted verbally and never recorded. The match did its job: it stopped a payment that nobody in finance could substantiate and routed it to the person who can.
Most people describe three-way matching as fraud prevention. In a make-to-order shop the bigger return is cost accuracy. An unmatched price increase does not just overpay a supplier — it silently understates the cost of the job it belongs to, and the estimator keeps quoting future work off a number that was never true.
Setting tolerances
A match that fails on every rounding difference gets switched off within a month. Tolerances exist to keep the control alive by absorbing noise while still catching signal. Three settings matter.
- Price tolerance — the variance you will accept between order price and invoice price, usually expressed both as a percentage and an absolute cap, so a 5% tolerance on a $40,000 line does not quietly wave through $2,000.
- Quantity tolerance — how much over-delivery you will accept and pay for. This should be tighter than price tolerance, and often set to zero for anything made to order, since you did not want the extra units in the first place.
- Ancillary handling — whether unplanned freight and surcharges hold the invoice or are allowed through and posted to a variance account. Holding everything is safest; holding nothing is common and expensive.
Tolerances should be set per category, not globally. A 2% swing on commodity fasteners is noise. A 2% swing on a $60,000 subcontract is a conversation.
The exceptions that matter
A mature matching process is judged by how it handles the cases that do not match. Four recur constantly.
- Received, never invoiced. Goods have arrived but the supplier invoice has not. Check whether receipt-based valuation or accruals already capture the amount; missing invoices do not automatically mean the cost is absent from the books.
- Invoiced, never received. Either the receipt was not recorded or the goods genuinely did not arrive. Both are serious, and only one is the supplier's fault.
- Short shipment closed silently. The supplier ships five of six and invoices five. Nothing looks wrong, but a job is now missing a part and the purchase order is still nominally open for one unit.
- Substitution. The supplier sent an equivalent item at a different price. The invoice does not match the order line because it is not the same thing, and someone with technical judgement — not accounts payable — has to accept it.
How Datum handles it
Datum connects purchase orders, goods receipts and vendor bills so the team can review the records behind a purchase. Receipt and bill information remain part of the operational context rather than being reduced to a supplier reference alone.
Use the supported billing and approval workflow to review quantities, prices and bill-related cost changes. A document match, an approval and a payment are separate steps; a matching result should not be described as an automatic release of funds.
Related stock costs can be examined through receipt cost layers and cost amendments. The choice between Datum Accounting and supported external books is a separate part of the setup.
What to check in your setup
- Walk through partial receipts, previous bills, price changes and extra charges using your own purchasing examples.
- Confirm which validations and approval controls are available in your edition.
- Agree who reviews differences; require a demonstration before treating automated tolerance rules as an included capability.
Related questions
What is the difference between two-way and three-way matching?
Two-way matching compares only the purchase order and the invoice. Three-way matching adds the goods receipt, so you confirm that what you are paying for actually arrived. Two-way is common for services and subscriptions where there is nothing to receive. Three-way is the standard for physical goods.
What is a matching tolerance?
A matching tolerance is the small variance you are willing to accept without human review — for example, an invoice up to 2% or $25 above the purchase order price. Tolerances stop the finance team from investigating rounding differences and freight rounding while still catching real overbilling.
Does three-way matching require a formal purchase order for everything?
It requires one for anything you want matched. Operations that buy off email or by phone can still adopt three-way matching, but they need to record the commitment as a purchase order at the moment it is made rather than reconstructing it when the invoice arrives.
What happens when a supplier ships partial quantities?
Each receipt is recorded separately against the same purchase order line, and each supplier invoice matches against the received quantity available at that point. The purchase order stays open with a remaining balance until the full quantity is received or the line is closed short.