Accounts Receivable Aging: What It Is & How Bookkeepers Use It

You're on a collections call. The customer says they sent payment three weeks ago. Your AR aging report shows $8,400 sitting in the 61-90 bucket. Someone is wrong, and you need to figure out who.

This is the moment the AR aging report earns its place in your monthly close. It's not just a list of old invoices. It's the document that tells you where the money is, who owes it, and how long they've been holding it. Bookkeepers who run it consistently catch problems early. Those who skip it find out months later when cash doesn't match the P&L.

TL;DR

Accounts receivable aging groups unpaid customer invoices by how long they have been outstanding. Use it monthly to tie AR to the general ledger, prioritize collections, catch misapplied payments, and decide when a reserve or write-off discussion needs documentation.

Quick Definition

What is accounts receivable aging?

Accounts receivable aging is a report that groups every unpaid customer invoice by how long it's been outstanding. The standard buckets are 0-30, 31-60, 61-90, and 90+ days past due. A business with Net 30 terms should have 80% or more of its total AR in the 0-30 bucket. Dollar amounts drifting into the 61-90 or 90+ range signal collection risk (or a bookkeeping error). Bookkeepers run it at month-end to flag past-due accounts, review payment application, and decide whether a bad-debt reserve is needed.

AR Aging Snapshot

AR Aging Example

A client has $47,000 of open AR: $31,000 current, $8,400 in 31-60, $5,100 in 61-90, and $2,500 over 90 days. The $31,000 bucket is cash planning. The $8,400 bucket needs reminder emails. The $5,100 bucket needs a named collections owner. The $2,500 bucket should not be written off automatically; first confirm whether the customer paid without remittance, disputed the invoice, or is genuinely uncollectible.

Key Takeaways

• Standard aging buckets: 0-30, 31-60, 61-90, and 90+ days past due. The 90+ column is where write-off conversations start.
• Healthy benchmark: On Net 30 terms, at least 80% of AR dollars should sit in the current (0-30) bucket. Anything else needs attention.
• Missing remittance is the most common cause of a "paid but aging still shows open" dispute: the customer sent money but didn't tell you which invoice it covered.
• IRC §166 requires actual worthlessness before you can deduct a bad debt on a tax return. Slow-paying doesn't qualify; documented collection failure does.
• Short-pays miscoded as bad debt inflate write-offs and understate the sales discount account. Check before writing off.
• AR aging vs. accrued revenue at year-end: open invoices on the aging are already recognized revenue under accrual. Don't double-count them.

What Accounts Receivable Aging Actually Is

AR aging is a subledger report. It lists every open invoice for every customer, grouped by how many days past the due date the invoice has gone unpaid. The total of all open invoices on the aging should tie exactly to the AR control account on your general ledger. If it doesn't, a journal entry was posted directly to AR without a customer record. That's worth investigating before you close.

The four standard buckets work like this:

• 0-30 days: Invoices due within the last 30 days. Normal territory for Net 30 accounts.
• 31-60 days: Mildly past due. First follow-up range.
• 61-90 days: Seriously past due. Active collection needed. Payment disputes often surface here.
• 90+ days: Collection risk. Reserve or write-off decisions live here.

The aging date matters. Most bookkeepers run the report "as of" the last day of the month. If you run it mid-month, buckets shift and the picture looks different. Use a consistent as-of date so the month-over-month trend means something.

One distinction to understand: the aging measures days past the invoice due date, not the invoice date. A Net 30 invoice issued October 1 has a due date of October 31. On November 15, it would appear in the 0-30 bucket (15 days past due), not the 31-60 bucket.

How Bookkeepers Use the AR Aging Report

The AR aging is a working document, not just a printout. Here's what a month-end close review looks like in practice.

Step 1: Pull the report as of month-end. Run it before you close the period. You want the balances current.

Step 2: Check the total against the GL. Pull your AR balance from the trial balance. The aging total should match to the cent. A mismatch usually means a journal entry hit the AR account directly. Find it and fix it.

Step 3: Review anything in the 61-90 bucket. Flag every customer with an invoice past 60 days. These need a call or email before they slip further. Assign follow-up by the next business day, not "sometime next week."

Step 4: Escalate the 90+ bucket. Invoices over 90 days past due have two possible futures: collected or written off. Decide which, and document the decision. If you're recommending a write-off, make sure you have evidence of collection attempts for the tax file.

Step 5: Check payment application on any disputed invoices. If a customer says they paid, look at the payment application before arguing. The issue is usually a missing remittance, covered below.

The accounts receivable article covers the underlying AR workflow in QBO, including how invoices move through the system and how payments get matched. Start there if you're new to how AR records are built.

Common Gotchas at Month-End

Three situations create most of the AR aging cleanup work. Knowing them upfront saves hours.

Stale Balances from Short-Pays Miscoded as Bad Debt

A customer sends $940 against a $1,000 invoice. They deducted $60 as a "return" or "adjustment." The bookkeeper, not seeing a credit memo, codes the $60 short as Bad Debt Expense and marks the invoice paid.

The problem: the $60 reduction might not be a bad debt. It could be a pricing dispute resolved with a discount, an unapproved deduction, or a legitimate return that should go against a Sales Returns and Allowances account. Booking it as bad debt overstates bad debt expense and understates the correct contra-revenue account. At tax time, the bad debt deduction may not hold under IRC §166 because the debt was collected, just not in full.

The fix: don't code short-pays as bad debt without documentation. If the customer took a discount they weren't entitled to, that's a collections issue or a dispute, not a write-off. If the discount was approved, use a Sales Discount account, not Bad Debt.

Open Invoices Misapplied Across Multi-Invoice Payments

A customer owes invoices #1021, #1022, and #1023. They send one check for the combined amount but don't send remittance advice specifying which invoices it covers. The bookkeeper matches the payment to #1021 (the oldest or the largest). #1022 and #1023 stay open on the aging.

A month later, the customer's team calls about invoice #1022 being past due. They think it's paid. The check cleared their bank. Neither side is wrong. The payment hit your bank account; it just wasn't applied to the right invoices.

Missing remittance advice is the single most common reason AR aging shows "past due" on invoices a customer believes are settled. The fix is procedural: when a lump-sum payment arrives without remittance, call the customer before posting. Get the invoice breakdown. Apply it correctly. Note the call in the customer record.

For the payment reconciliation process more broadly, this scenario is why remittance advice handling is its own workflow step.

AR Aging vs. Accrued Revenue at Year-End

At year-end, some bookkeepers see open invoices on the aging and also enter accrued revenue for the same unbilled work. That creates a double-count.

Here's the distinction:

• Open invoices on the aging: Already billed. Already revenue (under accrual). Living in AR as an unpaid balance.
• Accrued revenue: Work performed but not yet billed. Goes to the books as Accrued Revenue (asset) and Revenue (income). No invoice in the system yet.

If an invoice appears on your AR aging, it's already been recognized as revenue. Don't accrue it again. Only accrue work that's been performed but hasn't been invoiced as of the last day of the period.

This confusion most often surfaces when a client delays invoicing past the month-end. The work is done in December, the invoice goes out January 3. The bookkeeper asks: "Do I have December accrued revenue?" Yes, if there's no invoice in the system. But if the December invoice was created and is sitting open on the aging, the revenue is already there.

How Growthy Handles AR Aging

Growthy pulls bank and payment platform transactions as they clear and matches them against open invoices in your books. When a lump-sum deposit arrives without remittance, it flags the transaction for review instead of guessing at invoice application. You see the candidates, confirm the match, and move on. The routine matching categorizes automatically on returning books at 90%+ accuracy. The edge cases surface to you for review and approval.

The features overview shows how the matching layer works across AR, AP, and bank rec.

FAQ

How often should I run the AR aging report?

Run it at the end of every month as part of your close checklist. If you have clients with high invoice volume or slow-paying customers, a weekly pull in the 31-60 bucket helps you catch things before they hit 90 days.

What does it mean when the AR aging total doesn't match my balance sheet?

It means a journal entry was posted directly to the AR control account without going through a customer invoice. This bypasses the subledger and creates a permanent mismatch. Find the journal entry, reverse it, and re-enter it correctly as a customer transaction.

When can I write off an AR balance as bad debt under IRC §166?

Section 166 requires the debt to be actually worthless, not just slow-paying. To support the deduction, document your collection attempts: emails, calls, demand letters, any response from the customer. If the customer has filed bankruptcy, get that documentation. A high AR aging balance alone doesn't satisfy §166. You need evidence that collection is genuinely not possible.

Should I include current (not-yet-due) invoices in my AR aging?

Yes. The aging report typically includes all open invoices, including those in the 0-30 bucket that aren't past due yet. This gives you a complete picture of total outstanding AR, not just the past-due portion. The "current" column shows what's coming due in the next 30 days.

What's the difference between AR aging and AR subledger reconciliation?

AR aging groups invoices by how old they are. AR subledger reconciliation compares the total of all open customer balances (from your customer center) to the AR account on the GL. They answer different questions: aging tells you how overdue the balances are; subledger reconciliation tells you whether the books agree on the total. Do both every month.

Running a clean AR aging each month is one of the fastest ways to stay ahead of cash flow problems. Bad debt reserves, §166 write-offs, and collections disputes all start here.

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Author note: Bobby Huang is a partner at SDO CPA and creator of Growthy. Growthy is bookkeeping software, not a CPA firm. This content is educational, not tax, legal, or accounting advice. Full disclaimer.

Related: Accounting & Bookkeeping Glossary, Accounts Receivable (AR): What It Is & How It Works, Payment Reconciliation Guide