Who should pay for a reconciliation, the 3PL or the brand?

Whoever needs the answer more. In practice, a 3PL defending a large claim or protecting a key account, or a brand deciding whether to renew. The method is the same either way, and the evidence is only persuasive if the other side can check it, so share the working.

Can a brand reconcile without access to the 3PL's WMS?

Usually, yes. Most 3PL client portals export on-hand by SKU, receipts against ASNs, shipments, adjustments and returns. Those five, plus the brand's own ASNs and orders, cover most of the method.

Field guide · 3PLs and their clients

3PL inventory reconciliation:
settling a dispute with evidence

A brand says it sent 1,200 units. The 3PL's WMS says 1,080. Both are usually right about something. This guide shows how to reconcile the two records item by item, classify every difference, and end the argument with evidence instead of a write-off split down the middle.

Updated 19 September 2026
Written by WMSAudit
A Ravenspire LLC company
9 min read

Short answer

3PL inventory reconciliation compares a client's expected inventory with the 3PL's WMS balance item by item, at a common cut-off, in base units. Most of the gap usually falls into a few types: timing, status, receiving shortages against the ASN, unit-of-measure conversion, and returns in process. Genuine loss is what remains after those are explained, and each type needs different evidence.

Three records, not two

A client inventory dispute looks like two numbers disagreeing: the brand's expected balance and the 3PL's WMS balance. There are actually three: the brand's ledger (built from ASNs sent and orders shipped), the 3PL's WMS ledger (built from receipts and transactions), and the physical stock. Each is correct about the events it recorded, and each is blind to the events it didn't.

That's why splitting the difference or writing it off doesn't end the argument: the mechanism that produced the gap is still running. The only durable resolution is to classify every unit of difference by why the two ledgers disagree.

A worked example: 1,200 expected, 1,080 on hand

One SKU · brand ledger vs 3PL WMSIllustrative arithmetic

Reconciliation of a 120-unit difference between a brand and its 3PL
Difference type	Units	Evidence
Brand expects	1,200	ASNs sent − orders shipped, from the brand's system
Timing: orders shipped after cut-off	−36	Ship confirmations timestamped after the snapshot
Receiving: ASN said 10 cases of 12, arrived as 10 of 10	−20	Receipt count vs ASN; the vendor's pack changed
Status: damaged on receipt, in hold	−24	Hold-location balance, with status history
Returns received, not yet inspected	−28	Returns queue: counted by the brand as restocked, not yet available in the WMS
Unexplained	−12	No transaction explains it: investigate as possible loss
3PL WMS available on hand	1,080	1,200 − 36 − 20 − 24 − 28 − 12

Gap120 units· explained by evidence108· genuinely in question12

A 120-unit argument has become a 12-unit investigation and three process fixes: agree the cut-off, send the pack change back to the vendor, and decide how returns in inspection are reported. Without the classification, the brand sees 10% shrink and the 3PL sees a client who can't count.

The seven difference types

Timing: Receipts, shipments or adjustments on different sides of the snapshot in the two systems. They reconcile by themselves once the cut-off is aligned.
Receiving vs ASN: The ASN said one thing and the dock counted another. Shortages that were never claimed become the brand's "missing" stock.
Unit of measure: The brand thinks in eaches and the 3PL receives in cases, or the pack changed. A difference that's a clean multiple of a pack is a conversion, not a loss. See unit-of-measure errors.
Status: Stock that's physically present but held: damaged, QA, quarantine, expired. The brand counts it; the 3PL's available figure doesn't.
Returns in process: Received but not yet inspected or restocked, so it's in one ledger and not the other.
Shipment errors: A mis-pick shipped the wrong SKU: one item short, another over by the same amount. Look for equal and opposite differences across SKUs.
Genuine loss: What remains after the six above: shrink, unrecorded damage, disposal. Only this part belongs in a loss claim.

How to reconcile

Step 01

Agree one cut-off, in writing

One date and time, one time zone. Both sides export as of that moment. Most disputes shrink by a third at this step alone.

Step 02

Convert everything to base units

Do the conversions yourself from each side's pack data. Don't accept either system's converted figures, or a UOM difference disappears into the arithmetic.

Step 03

Compare by SKU, then by SKU and status

Totals hide offsetting differences. Mis-ships show as equal and opposite across SKUs; status differences show only when available and held are compared separately.

Step 04

Classify every unit of difference

Use the seven types, with the evidence record that supports each classification. Whatever can't be classified stays "unexplained". Don't force it into a category.

Step 05

Fix the mechanisms, then settle the remainder

Timing, UOM and returns-reporting differences are process fixes. Only the unexplained remainder is a commercial conversation about liability.

For 3PLs: the records that win disputes

Receipt count against ASN, line by line, with the variance recorded and communicated to the client the same day.
Status history: when stock went into hold, why, and who released it.
Adjustment reason codes that name a mechanism. COUNT VAR wins nothing in a dispute.
Client-visible reporting of held, damaged and returns-in-process quantities, so the client's ledger can include them.
Pack changes logged with the date first received, and the client notified.

For brands: what to ask your 3PL for

On-hand by SKU and status, as of an agreed cut-off
Receipts against your ASNs, with counted quantity and variance
Shipments with ship-confirm timestamps
Adjustments with reason codes
Returns received, inspected and restocked, with dates

Most 3PL portals export all five. With your own ASNs and order history, that's enough to classify nearly every unit of a dispute.

The operational takeaway

In a 3PL relationship, an unexplained inventory gap costs more than the units: it costs trust, and eventually the account. Classifying the gap turns an argument into a short list of process fixes and a small, honest remainder.

The same method underpins three-way inventory reconciliation inside a single operation.

Questions

Who should pay for a reconciliation, the 3PL or the brand?: Whoever needs the answer more. In practice, a 3PL defending a large claim or protecting a key account, or a brand deciding whether to renew. The method is the same either way, and the evidence is only persuasive if the other side can check it, so share the working.
Can a brand reconcile without access to the 3PL's WMS?: Usually, yes. Most 3PL client portals export on-hand by SKU, receipts against ASNs, shipments, adjustments and returns. Those five, plus the brand's own ASNs and orders, cover most of the method.