The problem
Your suppliers are billing above contract, and nobody is checking
Price drift hides in lines too small to argue about and too numerous to review. An invoice price audit compares every line to the contract that was actually in force that day.
The error you never see
Overbilling on material spend is rarely fraud and almost never obvious. A price list expires and the supplier reverts to list. A quote applies to one job and quietly follows the SKU onto three others. A part number changes and the new one was never contracted. Each line is small enough to approve without a second thought, and there are thousands of them a month.
Why a normal AP review misses it
Accounts payable is checking that an invoice is arithmetically correct, matches a purchase order, and has not been paid twice. None of those checks compare the unit price to the contract in force on the invoice date — the one comparison that catches price drift.
- A three-way match confirms you received what you ordered, not that you paid the agreed price for it.
- Duplicate payment audits catch the same invoice twice; they say nothing about a wrong price billed once.
- Spot checks cover a few percent of lines, and the errors are spread thinly across all of them.
- Nobody reconciles the price list version history against invoice dates by hand — it is too slow to be worth it.
What a real invoice price audit checks
- Every line matched to the contracted price in effect on the invoice date, not today's price.
- Unit of measure normalized before comparison, so a per-square contract can be checked against a per-bundle invoice.
- Credits paired with their rebills, so a correction is not counted as both an overcharge and an undercharge.
- Unmatched lines explained by reason — unknown SKU, no price in effect, unit mismatch, substitution, freight — instead of dumped in one bucket.
- Undercharges classified as standing, quoted, or isolated, because a persistent discount is a negotiating fact.
Sizing the problem before you buy anything
Take annual spend against contracted price lists, multiply by a conservative one to two percent error rate, and subtract whatever share of lines you genuinely audit today. The remainder is what walks out the door each year. The calculator does this arithmetic and shows the recoverable portion separately, since not every documented error gets collected.
Common questions
- What counts as an invoice price error?
- Any line billed at a unit price different from the contracted price that was in effect on the invoice date, once units of measure are normalized and credits are paired with their rebills.
- How much do contractors typically lose to it?
- One to three percent of contracted material spend is the range we see where nobody audits systematically. It concentrates in a handful of suppliers and product families rather than spreading evenly.
- Can we not just do this in a spreadsheet?
- For one supplier and a stable price list, yes. It breaks down once you have dated price list versions, unit-of-measure differences, substitutions, and credit or rebill pairs to reconcile.
- How far back can we claim?
- That depends on your supplier agreements and local limitation periods. Most agreements allow at least the current contract term, which is why loading historical invoices at the start is worth the effort.
See your own numbers
Audit your first 500 invoice lines free. No card, no sales call.