What it means
The clock starts at the due date, not the invoice date. An invoice issued on 1 March with 30-day terms is due on 31 March and becomes past due on 1 April, so payment terms have to be recorded accurately for the status to mean anything.
Finance teams sort past due balances into ageing buckets, most commonly 1 to 30 days, 31 to 60, 61 to 90 and over 90 days. The buckets exist because collection probability drops steeply with age, and a balance sitting beyond 90 days is treated very differently from one that slipped by a week.
Past due status drives real decisions rather than just reporting. Credit controllers use it to place accounts on hold, sales teams use it before agreeing new orders, and lenders use it to classify loans and set aside provisions for expected losses.
Being past due is not always a sign of financial distress. A great deal of late payment is administrative, caused by a disputed line, a missing purchase order number or an invoice sent to the wrong inbox, which is why the first collection step should be a query rather than a demand.
The accounting consequence is provisioning. Once a balance is sufficiently overdue, the business recognises an allowance for doubtful debts against it, reducing reported profit before any formal write-off happens.
In practice
Real-world examples.
Example
A building supplier runs a weekly ageing report and finds $240,000 of receivables past due, of which $52,000 is beyond 90 days. It stops delivering to the three worst accounts and refers the oldest balance to a collection agency.
Example
A homeowner misses a mortgage instalment by eleven days. The loan is past due and a late charge applies, but because it clears before the 30-day mark the lender does not report it to the credit bureau.
Example
A software vendor discovers that a large past due balance is not a payment problem at all: the customer's accounts payable system rejected the invoice because the purchase order number was missing. Reissuing the invoice correctly clears $86,000 in a single week.
Formula
Calculation
Days past due = Current date - Due date
Late fee = Outstanding amount x Monthly late fee rate x Number of months past due
A printing company issues an invoice for $18,000 on 1 March with net 30 terms, making it due on 31 March. The customer has still not paid on 15 May. April contributes 30 days and May contributes 15, so the invoice is 45 days past due and sits in the 31 to 60 day ageing bucket.
The contract allows a late fee of 1.5% a month. One month's fee is $18,000 x 0.015 = $270, and 45 days is 1.5 months, so the accrued late fee is $270 x 1.5 = $405. The customer therefore owes $18,000 + $405 = $18,405, and the printing company's credit policy places the account on hold until the balance clears.Case study
Seen in the real world.
Belltower Interiors is an illustrative, fictional commercial fit-out contractor that grew quickly and stopped watching its ageing report. Revenue reached $9,000,000 while receivables climbed to $2,400,000, roughly 97 days of sales outstanding, and almost $700,000 of that was more than 90 days past due.
The finance manager sorted the past due balances by cause rather than by size. Around 40% were genuine disputes over variations that had never been formally approved, 35% were administrative failures such as missing reference numbers, and only 25% reflected customers who could not or would not pay. Belltower had been sending identical chasing letters to all three groups.
The fix was procedural: variations approved in writing before work began, invoices validated against the customer's reference format before sending, and a separate escalation path for genuine non-payers. Days sales outstanding fell to 64 within two quarters and the over-90-day bucket halved, an illustrative reminder that most past due balances are created upstream of the collection call.
Watch out
Common mistakes.
- Counting days from the invoice date instead of the due date, which overstates how overdue a balance really is and damages relationships with customers who are paying on time.
- Treating every past due balance as a credit problem, when a large share is caused by disputes and administrative errors that a phone call would resolve.
- Leaving old past due balances on the ledger at full value, which overstates assets and delays the provision that should already have been recognised.
Questions
People also ask.
When does a past due account get written off?
Practice varies, but many businesses provide fully against balances beyond 90 or 120 days and write them off once collection efforts have genuinely been exhausted.
Does past due mean the same thing as delinquent?
They are close, though delinquent tends to be used for loan instalments and carries a stronger implication of credit deterioration than a merely late trade invoice.
Can late fees always be charged?
Only if the contract or the applicable local rules allow it, and many businesses waive the fee for good customers while still using it as leverage with persistent late payers.
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