Vendor Reconciliation

By Nupur Mittal

Co-founder at OCTA — works with accounting firms on month-end close and reconciliation automation.

A vendor reconciliation matches a supplier's statement of account to the company's accounts payable subledger, then explains every difference — timing gaps, unrecorded invoices, goods received but not yet invoiced (GRNI), unclaimed credits, and disputed amounts. It confirms the AP balance in the books is complete and accurate. This page walks through the full process and format step by step, the red flags a careful reviewer watches for, and how accounting firms run vendor reconciliations faster with OCTA Flow while a human approves every entry.

Why vendor reconciliation matters, and where it goes wrong

Accounts payable is one of the few balance-sheet accounts where the other party sends you a second opinion every period: the vendor's statement of account. That makes vendor reconciliation different from most controls — it isn't just checking your own books, it's checking your books against an independent third-party record. When the two don't agree, the gap usually means something specific: an invoice the vendor sent that never made it into the subledger, a payment you made that hasn't been applied yet, goods that arrived before the invoice did, or a credit note sitting unclaimed. Left unreconciled, any of these can misstate the AP balance, delay a legitimate payment, or let a real liability go unrecorded for months.

For a firm, the pain is the sheer number of moving parts per vendor: dozens of invoices, partial payments, credit memos, and purchase orders, each needing to be matched on invoice number, date, and amount — with the added complication that neither the vendor's cut-off nor its formatting matches yours. A vendor statement showing a balance that doesn't tie to the subledger isn't cosmetic; it's either an unrecorded liability the financial statements are missing, a dispute that needs resolving before the next payment run, or a vendor who's about to call asking why they haven't been paid for an invoice you never received. The goal is a fully-explained reconciliation for every vendor, every period — not a balance close enough to move on from.

The vendor reconciliation process, step by step

A proper vendor reconciliation follows a consistent sequence. The steps below are the full procedure OCTA Flow executes; they also stand alone as a best-practice process any AP team can follow.

1. Confirm opening balances. Compare the opening balance on the vendor's statement to the opening balance in the AP subledger for the same vendor and period. A difference here usually points to a prior-period reconciling item that was never cleared — resolve it before reconciling the current period, or it will keep reappearing.

2. Match transactions. For every line on the vendor statement, locate the corresponding entry in the AP subledger. Match on invoice number, invoice date, and amount, allowing ±3 days on dates for mailing and posting timing. Anything that matches on all three is cleared. Anything that doesn't match on either side becomes a reconciling item.

3. Categorize the reconciling items. Sort every unmatched item into one of the following:

• Invoices in the GL, not on the vendor statement — could be a timing difference from the vendor's statement cut-off, a duplicate entry on your side, or an item the vendor is disputing.
• Invoices on the vendor statement, not in the GL — a potential unrecorded liability. If the goods or services were received, it needs to be booked.
• Payments in the GL, not acknowledged on the vendor statement — a payment that's in transit or has been misapplied by the vendor.
• Credits on the vendor statement, not in the GL — an unrecorded credit note (debit memo) that reduces what's actually owed.
• Disputed items — invoices that exist on both sides but disagree on quantity, price, or tax.

4. Check for goods received, not invoiced (GRNI). Where open purchase orders are available, identify any PO with a goods-received date but no matching vendor invoice yet. These GRNI items represent a real liability — the goods are on your shelves or in your systems — even though no invoice exists on either side of the reconciliation. They need to be accrued, not ignored.

5. Verify payment matching. Where remittance advices are available, confirm each payment recorded in the GL corresponds to a remittance sent to the vendor, and that the vendor has actually applied it on their statement. A payment the vendor hasn't applied is the single most common cause of a vendor calling about a "past due" balance that isn't really past due.

6. Compute the closing balance. Compare the vendor statement's closing balance to the AP subledger's closing balance for the same vendor and period. The difference is the sum of every unmatched item — it should net to zero once every reconciling item is accounted for.

7. Age the open items. For every unmatched item, calculate days outstanding from the invoice or item date:

• 0–30 days — Current
• 31–60 days — Aging
• 61–90 days — Overdue
• 90+ days — Long-overdue; investigate and consider write-off or escalation

8. Propose adjusting entries. For every unrecorded invoice or credit note confirmed as valid, prepare the entry for a person to review and post: Dr Expense/Asset, Cr AP for an unrecorded invoice; Dr AP, Cr Expense for an unrecorded credit note. The reconciliation isn't complete until these are recorded or formally approved.

The vendor reconciliation format (worked example)

The two-sided format ties the vendor's balance and the subledger's balance to the same figure. Here's a worked example for a single vendor at March month-end.

Vendor: Meridian Supply Co. — Period: March 2026

Both sides tie to $57,200. Invoice INV-3381 becomes an adjusting entry the firm posts to the books (Dr Expense/Asset $2,950 / Cr AP $2,950); the $1,200 payment in transit is a timing item that will clear once Meridian applies it to their records next period.

A separate item surfaces from the purchase-order check and doesn't touch the tie-out above, because no invoice exists yet on either side: PO #4471 shows goods received on 3/29 per the receiving report, but no vendor invoice has arrived. This is a GRNI accrual — an estimated $1,500 liability for goods already received. It's disclosed and accrued separately (Dr Inventory/Expense $1,500 / Cr GRNI Accrual $1,500) so the balance sheet reflects the obligation even before Meridian's invoice shows up, rather than waiting for a bill that could land a month later.

Key controls and red flags

The difference between matching transactions and a reliable vendor reconciliation is what you watch for. A careful reviewer flags:

• A vendor statement balance that doesn't equal the AP subledger balance beyond a rounding amount — the most serious flag
• Invoices on the vendor statement over 60 days old with no corresponding GL entry — unrecorded liability risk
• Payments recorded in the GL that the vendor hasn't acknowledged — misapplication risk, and the likely source of "past due" calls
• Duplicate invoice numbers in the AP subledger — a possible double payment
• Credits on the vendor statement that haven't been claimed — money left on the table
• GRNI items older than 30 days with no vendor invoice received — an accrual that's overdue for review
• Tax discrepancies (sales tax) between the vendor's invoice and what was booked

Catching these consistently, for every vendor and every period, is what turns a vendor reconciliation from a filing exercise into a genuine control over accounts payable.

What a completed vendor reconciliation produces

A finished vendor reconciliation isn't just a matched spreadsheet — it's a documented workpaper a reviewer can sign off on and an auditor can follow. A complete package includes:

How OCTA Flow automates vendor reconciliation

OCTA Flow does the mechanical matching for you and leaves the judgment — and the sign-off — with your team. The workflow mirrors the process above:

1. Pick the Vendor Reconciliation Skill. Flow already knows the full procedure: match transactions, categorize reconciling items, check open purchase orders for GRNI, verify payment matching, and age every open item.
2. Connect your data. Point Flow at the vendor's statement and your AP subledger, or upload the period's files. Open purchase orders and remittance advices sharpen the reconciliation further when they're available, but aren't required to run it.
3. Run. Flow matches every invoice, payment, and credit it can on invoice number, date, and amount, sorts what's left into unrecorded invoices, in-transit payments, unclaimed credits, disputed amounts, and GRNI, and builds the two-sided reconciliation.
4. Review findings by severity. Instead of a wall of matched lines, Flow surfaces only the exceptions — ranked by severity, each with a plain-English explanation and a recommended action: record the invoice, email the vendor, accrue the GRNI liability, or escalate an unexplained difference. Your team works the exceptions, not every line.
5. Sign off. Once the reconciliation ties and the entries are approved, Flow assembles the workpaper with the full audit trail intact.

The result: the line-by-line matching is done in a fraction of the time, and your people spend their hours on the invoices, credits, and disputes that actually need judgment.

Control and trust: Flow proposes, you approve

This is what matters most to a firm putting its name on the numbers: OCTA Flow never writes to your books on its own. Every adjusting entry and accrual is a proposal that a human reviews and confirms before anything is posted. Flow does the matching and shows its reasoning; a person makes the call.

That control model runs through the whole reconciliation:

• Findings, not silent changes. Flow raises what it found and what it recommends — you decide.
• Severity and escalation built in. An unreconciled difference or a stale GRNI accrual is flagged accordingly and can be escalated to a manager rather than quietly carried forward.
• A complete audit trail. Every match, proposed entry, approval, and override is logged, so the reconciliation is fully traceable end to end.

You get the speed of automation with the accountability of human sign-off — exactly what a liability account like accounts payable requires.

What the reconciliation draws on

To run a vendor reconciliation, Flow uses the same sources a preparer already works from:

• Vendor statement of account — the supplier's record of invoices, credits, and payments for the period (required)
• AP subledger — the company's accounts payable transactions for that vendor (required)
• Open purchase orders — used to identify goods received but not yet invoiced (GRNI) (optional)
• Remittance advices — payment notices sent to the vendor, used to confirm payments were received and applied correctly (optional)

Flow works from whatever your client has connected — it matches each input by its purpose, so it doesn't matter what the files are named or which vendor or accounting system they came from.

Related skills and terms

Frequently Asked Questions

How do you reconcile a vendor statement? Compare opening balances, match each transaction on the vendor statement to the AP subledger by invoice number, date, and amount, categorize what doesn't match (unrecorded invoices, in-transit payments, unclaimed credits, disputed amounts), check open purchase orders for goods received but not invoiced, and confirm the closing balances agree once every reconciling item is explained.

What is GRNI (goods received, not invoiced)? GRNI is a liability for goods or services a company has received but hasn't yet been billed for. It's identified by comparing purchase orders with a goods-received date against the vendor invoices on file — if the PO shows receipt but no invoice exists, the value should be accrued so the liability shows up on the balance sheet before the invoice ever arrives.

What's the difference between vendor reconciliation and accounts payable review? Vendor reconciliation matches one vendor's statement to the AP subledger, line by line, to confirm a specific balance is correct. Accounts payable review looks across the whole AP ledger — aging, duplicate payments, coding accuracy — as a broader control, and often relies on vendor reconciliations as supporting evidence.

What causes a vendor statement to not match the AP subledger? Common causes are an invoice the vendor sent that was never recorded, a payment that hasn't been applied by the vendor yet, an unclaimed credit note, goods received but not yet invoiced (GRNI), or a disputed amount where quantity, price, or tax doesn't match between the invoice and the booking.

How often should vendor reconciliations be done? At least monthly, as part of the close, for any vendor with meaningful invoice volume or balance. High-volume or strategic vendors are often reconciled more frequently so disputes and unrecorded liabilities surface before they affect a payment run.

Can vendor reconciliation be automated? The matching, categorization, aging, and exception-flagging can be automated and reviewed, while judgment calls — disputes, write-offs, GRNI estimates — stay with your team. That's the model OCTA Flow uses.

See how firms run faster, fully-explained vendor reconciliations with human sign-off → start a 30-day OCTA Flow trial.