Outstanding Invoices: How to Track, Chase & Close Open Balances (2026)

An outstanding invoice is any invoice you have issued that has not yet been paid. This includes:

• Open invoices — sent, within payment terms, not yet due
• Overdue invoices — past the due date with no payment received
• Disputed invoices — client has raised a question or objection
• Pending invoices — awaiting approval in a client's procurement system

Outstanding invoices represent your accounts receivable (AR) — the total money owed to your business. Managing outstanding invoices is essentially managing your AR. For broader context on this, see our accounts receivable management tips.

The terms are often used interchangeably, but they mean different things:

The foundation of managing outstanding invoices is a reliable payment tracking system. You need to be able to answer these questions instantly:

• How many invoices are currently outstanding?
• What's the total outstanding balance?
• Which invoices are overdue, and by how many days?
• When did I last follow up on each overdue invoice?

Option 1 — Spreadsheet: Use a Google Sheet or Excel tracker with columns for Invoice #, Client, Amount, Invoice Date, Due Date, Status, and Last Follow-Up. Use a filter to show only unpaid/overdue rows. Free to set up; requires manual discipline. Use our free invoice tracker spreadsheet as a starting point.

Option 2 — Dedicated tracker: InvoiceGrid gives you a visual Kanban board (Pending → Reminded → Follow-up → Paid), an aging overview, and a chase history log for every invoice. No manual status updates needed — you log actions as you take them and the system shows you what needs attention today.

Whatever system you use, the non-negotiable fields per invoice are: invoice number, client, amount, due date, current status, and the date and content of your last follow-up.

Not all outstanding invoices need the same urgency. Invoice aging categorises your outstanding balances by how overdue they are:

• Current (0 days) — invoices within payment terms. No chasing yet; send pre-due reminder 3–5 days before.
• 1–30 days overdue — recently overdue. Likely an oversight. Friendly follow-up tone. Most invoices get paid at this stage.
• 31–60 days overdue — serious delay. Firmer tone, reference late fees, set a payment deadline.
• 61–90 days overdue — escalation territory. Consider a formal letter and mention legal action.
• 90+ days overdue — collections or legal action. Evaluate whether to write off or pursue. See our bad debt write-off guide.

Use our free AR aging report tool to generate an aging summary from your invoice data instantly. For a detailed guide on aging reports, see invoice aging report guide.

1. Invoice sent → log immediately. Add the invoice to your tracker the moment you send it. Set the status to "Unpaid" and note the due date.
2. 3–5 days before due date → pre-due reminder. A brief, friendly email with payment details attached. Many clients appreciate the nudge and pay before the due date.
3. Due date (if unpaid) → polite reminder. Reference the invoice number, amount, and that it's due today. Make it easy to pay by including your payment details.
4. 7 days overdue → friendly follow-up. Assume it was overlooked. Keep the tone warm. Include the invoice as an attachment. Log this in your chase history.
5. 14 days overdue → firmer tone. Reference late fees if applicable. Request a specific payment date. Ask if there's a dispute or issue you're not aware of.
6. 30 days overdue → escalation warning. Mention that you'll need to take further action if not resolved by a specific date. Keep it professional but unambiguous.
7. 60+ days overdue → final notice. One last formal email before escalating to collections or legal action. Document everything.

See our comprehensive guide on how to chase unpaid invoices for the full escalation ladder.

These templates cover the most common outstanding invoice follow-up scenarios. Replace the bracketed fields with your details.

Outstanding Balance (Multiple Invoices)

Use when a client has several open invoices and you want to consolidate the follow-up.

Outstanding Payment Reminder (Single Invoice)

For a single overdue invoice, 7–14 days past due.

Letter for Outstanding Payment (Formal)

For 30+ days overdue where you want a more formal tone.

For a full library of templates at every stage, see our complete reminder email library, overdue invoice email templates, and collection letter templates.

The best way to manage outstanding invoices is to prevent them from becoming overdue in the first place. Key prevention strategies:

• Invoice immediately. Send the invoice the day you complete the work, not days or weeks later. Late invoicing signals low urgency to the client.
• Use shorter payment terms. Net 14 or Net 7 instead of Net 30 reduces the window for delay. See our guide on payment terms for choosing the right terms.
• Require deposits. A 25–50% upfront deposit reduces the total outstanding balance and filters out clients who won't pay. Our freelance contract payment terms guide covers how to structure this.
• Make it easy to pay. Include a direct payment link or your bank details in every invoice. Every extra step between "intent to pay" and "paid" increases the chance of delay.
• Send a pre-due reminder. A brief reminder 3–5 days before the due date catches invoices that are sitting in someone's inbox unread.
• Include a late fee clause. Clients are more likely to pay on time when they know a fee will accrue. See our guide to charging late fees.

If a client hasn't paid after multiple reminders, you have several escalation options:

• Formal demand letter — a legally worded letter explicitly requesting payment within a set deadline and stating the consequences of non-payment. See our demand letter templates.
• Small claims court — for amounts under the local small claims limit (£10,000 in the UK, $10,000–$25,000 in most US states). Fast, inexpensive, and no lawyer required. In England and Wales, file through Money Claim Online. See our guide on taking an unpaid invoice to small claims court.
• Debt collection agency — they collect the debt for a fee or percentage of the amount recovered. Good for larger amounts where legal action isn't practical.
• Write off the debt — if the cost of pursuing exceeds the amount owed, write it off as bad debt. See our bad debt write-off guide for the tax implications.