Can AI check my bills for mistakes?
Yes. Paste a bill next to last month's, and it flags new charges, price changes and math errors, then writes a short message to ask about them.
01Why bot
- Comparing two documents line by line is easy for AI.
- New fees and promo expirations are easy to miss by eye.
- It drafts the question to the company for you.
Sponsor slot · openFeatured tool for this task. A labeled card for one relevant tool.
Book this spot →02The prompt
Replace everything in [BRACKETS] with your own details, then paste it into your AI app.
You are a careful bill auditor. This month's bill (paste line items, no account numbers): [BILL] Last month's bill: [BILL] Your task: find anything that changed or looks wrong. Rules: - MUST list every new charge, price change and removed discount. - MUST check the math on the total. - NEVER assume a charge is an error; list it as a question. Give me: a table (item, last month, this month, change, question to ask) and a short message to the company.
03Steps
- Put two bills side by side.
- Run the prompt.
- Call or chat with the company about flagged items.
04What can go wrong
- Remove account numbers before pasting.
- Some changes are legitimate price increases.
05What to use
Any major AI chat app.
06Our test runs
2 runs, each with a different made-up sample. 1 of 2 passed every check.
Run 1 · Llama 3.3 70B · graded by GPT-OSS 120BOct 4, 2026Passed
The made-up sample:
[BILL]Last Month (2026‑09): - Service Plan (Basic) – $40.00 - Data Overage (2 GB) – $15.00 - Discount (Loyalty) – -$5.00 - Taxes – $7.00 - Total – $57.00 This Month (2026‑10): - Service Plan (Basic) – $40.00 - Data Overage (5 GB) – $30.00 - International Calls (10 min) – $8.00 - Discount (Loyalty) – -$5.00 - Taxes – $9.50 - Total – $82.50
- List every new charge, price change, removed discount
- Check the math on the total
- Never assume charge is error; ask as question
- Provide table with required columns and short message
- Didn't make up details we never gave it
What came back (excerpt):
I have reviewed the bill for this month and last month, and I have some questions regarding the changes. The data overage charge has increased, and there is a new charge for international calls.
Read the full answer
Here is the table of changes: | Item | Last Month | This Month | Change | Question to Ask | | --- | --- | --- | --- | --- | | Service Plan (Basic) | $40.00 | $40.00 | No change | - | | Data Overage | $15.00 (2 GB) | $30.00 (5 GB) | Price increase, new usage | Is the data overage charge correct for the usage? | | International Calls | - | $8.00 (10 min) | New charge | Is the international calls charge correct and expected? | | Discount (Loyalty) | -$5.00 | -$5.00 | No change | - | | Taxes | $7.00 | $9.50 | Increase | Is the tax increase correct and due to a rate change or usage? | Here is a short message to the company: "I have reviewed the bill for this month and last month, and I have some questions regarding the changes. The data overage charge has increased, and there is a new charge for international calls. Additionally, the taxes have increased. I would like to confirm that these changes are correct and expected. Could you please review and verify the math on the total, which is $82.50? I have recalculated the total as follows: $40.00 (Service Plan) + $30.00 (Data Overage) + $8.00 (International Calls) - $5.00 (Loyalty Discount) + $9.50 (Taxes) = $82.50, which appears to be correct. However, I would like to confirm that all charges are accurate and authorized."
Verify the table includes all required columns and the short message is included.
Run 2 · Llama 3.3 70B · graded by GPT-OSS 120BOct 25, 2026Passed with a catch
The made-up sample (a messier one):
[BILL]This Month: - Cloud Storage 500GB: $12.00 - Email Hosting (Basic): $5.00 - VPN Access: $8.00 - Loyalty Discount: -$3.00 (removed) - Misc. fee (see note): $2.00 - Tax (8%): $2.40 Total: $36.40 Last Month: - Cloud Storage 500GB: $10.00 - Email Hosting (Basic): $5.00 - Loyalty Discount: -$3.00 - Tax (8%): $1.44 Total: $13.44
- List every new charge, price change and removed discount
- Check the math on the total
- Never assume a charge is an error; list it as a question
- Provide a table (item, last month, this month, change, question) and a short message
- Didn't make up details we never gave it
What came back (excerpt):
I have reviewed my bill for this month and noticed several changes from last month. I would like to request clarification on the price increase for Cloud Storage, the new charges for VPN Access and the Misc. fee, and the removal of the Loyalty Discount.
Read the full answer
Here is the table of changes: | Item | Last Month | This Month | Change | Question to Ask | | --- | --- | --- | --- | --- | | Cloud Storage 500GB | $10.00 | $12.00 | Price increase | Why did the price of Cloud Storage increase by $2? | | VPN Access | $0.00 | $8.00 | New charge | What is the VPN Access service and why was it added to my bill? | | Loyalty Discount | -$3.00 | $0.00 | Removed discount | Why was the Loyalty Discount removed from my bill? | | Misc. fee | $0.00 | $2.00 | New charge | What is the Misc. fee for and why was it added to my bill? | | Tax | $1.44 | $2.40 | Increase | Is the tax calculation correct, and if so, why did it increase by $1.96? | Here is a short message to the company: Dear Billing Department, I have reviewed my bill for this month and noticed several changes from last month. I would like to request clarification on the price increase for Cloud Storage, the new charges for VPN Access and the Misc. fee, and the removal of the Loyalty Discount. I would also like to confirm that the tax calculation is correct. Please provide more information about these changes so I can understand my bill accurately. Thank you for your attention to this matter. Sincerely, [Your Name]
Ensure the answer verifies the total calculation.
How each run works: we fill the prompt with a made-up sample, run it once in Llama 3.3 70B, and GPT-OSS 120B grades the answer against the prompt's own rules. Word limits are counted by code, and every quote flagged as made up is checked against the full answer. Your results can differ. How we test.
Prompt packBills, Refunds & Disputes 10 step-by-step prompts that go further than this one, $15.
See what’s inside →