What is Invoice Aging?
Invoice aging tracks how long invoices have been outstanding — showing which are current, which are overdue, and which are at serious collection risk. Learn how to use invoice aging to manage cash flow and improve payment collection.
What Is Invoice Aging?
Invoice aging is the practice of tracking how long each outstanding invoice has been unpaid — measured in days past the invoice due date. It's the day-to-day companion to the accounts aging report. While the accounts aging report gives you a portfolio-level view of your receivables health, invoice aging focuses on the individual invoice level: "Invoice #247 for Bright Media is 23 days past due. I need to follow up." Invoice aging is critical because: - The longer an invoice ages, the less likely you are to collect it - Aging invoices are an early warning system for cash flow problems - Tracking aging helps you prioritize which invoices to follow up on first
The Aging Buckets
Invoices fall into these standard buckets: | Bucket | Description | |---|---| | Current | Not yet due, or paid | | 1-30 days past due | Just overdue — likely just forgotten | | 31-60 days past due | Moderately overdue — needs attention | | 61-90 days past due | Seriously overdue — at risk | | 90+ days past due | Critical — likely uncollectable or in dispute |
Why Invoice Aging Matters
The collection probability curve: | Days Overdue | Probability of Collection | |---|---| | 0-30 days | 90%+ | | 31-60 days | 70-80% | | 61-90 days | 50-60% | | 90-180 days | 20-30% | | 180+ days | <10% | Every day an invoice goes uncollected, the odds of ever collecting it drop. This isn't about being aggressive — it's about being realistic about your cash.
How to Track Invoice Aging
Method 1: Your Invoicing Software Modern invoicing platforms (like Eonebill) automatically track aging — showing you at a glance which invoices are overdue and by how many days. Method 2: Spreadsheet Tracking If you're doing this manually, create a simple aging schedule: | Invoice # | Client | Amount | Due Date | Days Past Due | Aging Bucket | |---|---|---|---|---|---| | 247 | Bright Media | $8,000 | Feb 15 | 23 days | 1-30 | | 241 | Crestwood | $12,000 | Jan 30 | 45 days | 31-60 | | 238 | Apex LLC | $5,500 | Dec 20 | 87 days | 61-90 | | 229 | OldTown Café | $3,200 | Nov 10 | 136 days | 90+ | Method 3: Sort Your AR by Due Date The simplest method: open your accounts receivable list and sort by due date — oldest first. That's your aging-driven to-do list.
Responding to Invoice Aging
Bucket 1: 1-30 Days Past Due Action: Friendly reminder Tone: Casual, helpful > "Hi [Client], just a heads up that Invoice #247 for $8,000 was due [date]. Just wanted to make sure it didn't slip through. Let me know if you need anything from our end!" Most invoices in this bucket are paid within a few days of the first reminder. People forget; a gentle nudge works. Bucket 2: 31-60 Days Past Due Action: Firm reminder + phone call Tone: Direct, professional Call the client. Ask directly: - Is there an issue with the invoice? - Is there a dispute about the work? - When can we expect payment? Try to identify if there's a real problem — cash flow issue, dispute, or just negligence — and address it. Bucket 3: 61-90 Days Past Due Action: Formal notice + demand Tone: Serious, formal Send a formal past-due notice. Consider: - Stopping work on any ongoing projects for this client - Requiring payment plan or partial payment before continuing - Reviewing your contract for collection/termination rights Bucket 4: 90+ Days Past Due Action: Final notice + collection action Tone: Final Send a final notice with a hard deadline. Options: - Collections agency referral - Small claims court (for smaller amounts) - Legal action (for larger amounts) - Write off as bad debt (and potentially claim as tax deduction)
Example: Following Up on an Aging Invoice
Day 1 (March 20): Invoice #251 for $4,200 becomes overdue (due date was March 19). Automatic email reminder sent. Day 7 (March 27): No payment. Send second reminder email. Day 14 (April 3): Still no payment. Send firm email: "Payment is now 15 days overdue. Please respond within 5 business days." Day 21 (April 10): No response to emails. Call client directly. Client says: "We've been having cash flow issues. Can we pay in two installments?" Negotiate payment plan. Day 25 (April 14): Send payment plan agreement: $2,100 now, $2,100 in 15 days. Client signs. Day 26 (April 15): Receive first installment ($2,100). Send receipt. Day 41 (April 30): Receive second installment ($2,100). Invoice closed. This proactive follow-up saved a $4,200 invoice that might otherwise have gone uncollected.
Preventing Invoice Aging
The best solution to aging invoices is prevention: 1. Clear payment terms — Net 30 or less; state clearly on every invoice 2. Easy payment options — Credit card, ACH, online payment portal 3. Upfront deposits — Collect 25-50% upfront, especially for new clients 4. Automated reminders — Send reminders the day an invoice becomes due 5. Regular AR review — Weekly review of aging report, not just when cash gets tight
The Bottom Line
Invoice aging is your early warning system — catch problems early, follow up consistently, and don't let invoices sit forgotten for months. The 1-30 day bucket is where most problems get solved with a single email or call. Waiting until 90+ days to act means you're likely writing it off. (Manage AR proactively →) (Speed up collections →) (Understand cash flow →) Key Takeaways: 1. Invoice aging = tracking how many days each unpaid invoice is overdue 2. The older an invoice gets, the less likely you are to collect it 3. Follow up at 1 day, 7 days, 14 days, and 30 days — escalating each time 4. Call clients when emails aren't working 5. After 90 days, consider collections or write-off Stop late payments before they age — Try Eonebill Free Eonebill's automated reminders and aging dashboards keep your invoices from aging into oblivion — follow up automatically, get paid faster. View Pricing → | Glossary Home → | Home →