What is a 3PL invoice audit?

A 3PL invoice audit is a line-by-line check of a third-party logistics invoice against two things: the prices you agreed in your contract, rate card or quote, and your own records of what actually happened - the orders you shipped, the stock you received, the space you used. Every billed amount is either proved right, proved wrong, or marked as needing evidence. Anything proved wrong becomes a dispute with your 3PL, backed by the contract text and the arithmetic.

Why 3PL invoices need auditing at all

A 3PL invoice is not one price. It is hundreds or thousands of small charges - receiving, storage, picks, packaging, labels, returns, account fees - each billed on its own unit, tier and rule. The total can look reasonable while individual lines are wrong: a pick billed at the wrong tier, a delivery received once and billed twice, a fee that was never in the contract, a surcharge that only applies in peak weeks billed in March.

Spot-checking does not catch this. The errors are small, they repeat every month, and each one is buried in an export nobody has time to recompute by hand. An audit exists to check all of it, every month, the same way.

What an audit compares

Every charge on the invoice should be provable from three sources:

• The invoice itself. Lines should add up, quantities should match their rates, and nothing should appear twice.
• The contract, rate card or quote. Each price, tier, free allowance, minimum and exclusion you agreed. This is the document that decides what a charge was allowed to be.
• Your own records. Your order export shows what shipped. Your receiving and inventory records show what arrived and what space it took. A charge for an order that never shipped fails against this source even if the rate is right.

An audit that uses only the invoice finds arithmetic errors. An audit that also uses the contract finds wrong rates and invented fees. An audit that uses all three finds charges for things that never happened.

The checks

A complete audit runs the same checks on every invoice:

• Duplicate charges: the same order, receipt or fee billed more than once.
• Rates above contract: a unit price higher than the rate card says.
• Line arithmetic: quantity times rate that does not equal the amount billed.
• Fees not in the contract: charge types your agreement never mentions.
• Recurring surcharges: the same extra appearing every cycle without a rule behind it.
• Peak fees out of season: peak or holiday surcharges billed outside the window the contract allows.
• Minimum top-ups: a top-up to a monthly minimum that is larger than the shortfall, or billed when you were already above it.
• Totals against your orders: what you were billed per order compared with what your store says shipped.
• Fee spikes: a charge type that suddenly costs far more than it did last month.

Each finding needs its evidence attached: the contract sentence with the agreed price, the record that shows what happened, and the arithmetic that produces the correct amount. A dispute without those three things is an opinion, and 3PLs refund proof, not opinions.

What you get

The output of an audit is not a feeling that the bill is high. It is a report in which every billed amount has a status - supported, a calculation mismatch, in conflict with the contract terms, needing more evidence, or not tested - and the statuses add up to the invoice total. Nothing is waved through, and nothing is accused without its working shown. For the amounts proved wrong, you get a dispute letter ready to send, the deadline it has to be sent by, and a record of every credit your 3PL promises, so a promised credit that never appears gets noticed.

By hand, by spreadsheet, or by service

You can audit by hand, and for a handful of orders a month you should: the quick check finds duplicates, new fees, lines that do not add up and fee spikes from the invoice alone, free. The cost of doing it by hand grows with order volume, because every line has to be matched against the contract and your records one at a time.

Audit services and software differ mostly in what they charge and what they need from you. Some take a percentage of whatever is recovered, which makes small errors not worth their time and large bills expensive. Some need integrations with your store and your 3PL's systems before they can start. Feeproof charges a flat monthly price by order volume - from $59 a month - works from the files you already have, and audits your three most recent invoices free, so the first audit shows what your invoices contain before you pay anything.

Start with the invoice you already have

The fastest first audit needs no setup: run the invoice quick check on your latest export, or turn your quote into a rate card you can check against. If you want the full check against your contract, the first audit is free.