You don’t need accounting software or a bookkeeper to catch this. You need your email inbox, which already contains nearly every receipt, invoice and payment confirmation your business has generated this month — and a free AI tool that’s very good at spotting patterns once you give it the raw list.

This is different from a one-off expense audit. Most “track your expenses with ChatGPT” guides show you how to do this once. The actual value comes from doing it every single month, consistently, so subscription creep gets caught within weeks rather than discovered eighteen months later when you finally go through your bank statement line by line.

Step 1 — Search Your Email for Receipts and Invoices

Don’t scroll through your inbox manually — search it with specific terms. Each of these searches, run separately, surfaces a different slice of your spending:

Restrict each search to the last month and work through the results. Most genuine business expenses will surface through at least one of these terms.

Step 2 — Copy the Raw Details Into a Document

For each result, copy three things into a simple text document: the vendor name, the date, and the amount. You don’t need to format it neatly — ChatGPT handles messy, inconsistent formatting well. A raw, unstructured list like the one below works perfectly:

Step 3 — Run the AI Categorisation and Money Leak Prompt

Paste your raw list into ChatGPT or Claude with this prompt:

You are a financial assistant helping me find wasted spend in my small business. Below is a raw list of receipts, invoices and payment confirmations I found in my email this month — vendor, date, and amount for each.

Please:
1. Categorise each item (e.g. software/subscriptions, office supplies, marketing, professional services, other)
2. Flag any subscription or recurring charge that looks like it might be forgotten or rarely used
3. Identify anything that looks duplicated or overlapping with another tool I'm already paying for
4. Tell me the 3 categories where I spent the most this month
5. If I provide last month's summary for comparison, tell me what changed significantly

Be specific and direct. Don't pad with generic financial advice — base everything only on the data below.

[PASTE THIS MONTH'S EMAIL RECEIPTS HERE]

Step 4 — Review Flagged Items First

Step 5 — Cancel or Consolidate What You Find

Act on this immediately, not “at some point.” If the report flags a subscription you haven’t used in months, cancel it the same day — before the next billing cycle locks in another charge. If two tools overlap, decide which one to keep and cancel the other.

Step 6 — Compare to Last Month Going Forward

Frequently Asked Questions