Nothing to hand? Load the — a small budget sheet built the way it should be — the , where a SUM stops one row short and a single cell in the copied column was edited by hand, or the , where a three-statement model carries a #REF!, a circular chain and a balance sheet that does not balance.
Paste the formulas — the scan is free
Press Ctrl+` in Excel (Cmd+` in Sheets) so the cells show their formulas rather than their results, select the block and copy. The browser splits it into real cells at their real addresses, tokenizes every formula, builds the reference graph, and reports what needs no judgement at all: error values, a SUM that stops one row above the last populated cell, the one cell in a copied column whose structure differs from its neighbours, constants typed inside formulas, circular chains, links to other workbooks, volatile functions and lookups with no exact-match argument or IFERROR guard. No upload, no AI, no cost.
The AI audits — this is the metered part
A modeller's pass over the whole sheet: what the sheet is trying to do, which of the browser's flags are real defects and which are deliberate, and the things only judgement catches — a formula that is syntactically fine and economically wrong, a sign convention that flips halfway down, a growth rate applied to the wrong base. The integrity checks are run explicitly and reported even when the answer is “not applicable”: totals tie to their components, the balance sheet balances, cash rolls forward, signs are consistent. Every finding carries the corrected formula, not just a complaint. Pricing is honest too: a worst-case amount is reserved before the run and only what the run actually uses is charged — the meter next to the button shows both.
Fix, re-paste, compare
The audit comes back as something you can act on, not just read. Copy the sheet with fixes applied hands back your own pasted block with every corrected formula already sitting at its own address, so you select the top-left cell and paste once instead of transcribing cell by cell; fixes that are not a formula for one cell (“move the 0.04 into a labelled input”) are listed separately as manual steps rather than dropped. Copy a single finding for the ticket or all of them for the review, export the findings, the integrity checks and the coverage reconciliation as CSV, email the open questions to whoever owns the sheet, and download the whole audit as Markdown or JSON.
Past audits are saved to your account, not just this browser, so a run made on one machine is there when you sign in on another. Pin any run as a baseline — usually the sheet as you first found it — and every audit after it opens with a named comparison: which findings cleared, which are still there and which are new, listed cell by cell rather than counted.
Does the free browser scan send my spreadsheet anywhere?
No. The scan parses the pasted block into cells, tokenizes every formula and builds the reference graph entirely in your browser, with no upload and no account. Nothing leaves the page until you press the audit button, and the three bundled examples replay a saved run without a sign-in or a charge.
Do I have to paste the values or the formulas?
The formulas. Press Ctrl+` in Excel or Cmd+` in Google Sheets to switch the sheet to Show Formulas, then select and copy the block. A paste of results tells the audit nothing about how the numbers were reached. Set the top-left cell of the block so the addresses in every finding match what you see in your own sheet — if that box is empty or unreadable the page says so rather than silently assuming A1.
Can I paste the corrected formulas straight back into my sheet?
Yes. “Copy the sheet with fixes applied” rebuilds the block you pasted with each corrected formula substituted at its own address and hands it back tab-separated, so formulas containing commas survive; select the cell the page names and paste. Anything the audit could not place — a fix with no single cell, or an address outside the block you pasted — is reported to you instead of being applied silently.
How do I tell whether my fixes actually worked?
Fix the cells, paste the sheet again and run it. The result opens with a comparison against your pinned baseline, or against the run before if you have not pinned one, naming the findings that cleared, the ones still present and any that are new — so a re-run answers “did that land?” rather than handing you a second list to read from scratch.
What does a run cost, and what happens if I am signed out?
A worst-case amount is reserved before the run and only what the run actually uses is charged; the meter beside the button shows both before you commit. Signed out, or with a balance below this model's minimum, the page says so at the button — naming the shortfall and offering sign-in or top-up — rather than failing after you submit. The browser scan and the three examples stay free either way.
What does the audit check beyond formula mechanics?
Model integrity, reported explicitly as pass, fail, unknown or not-applicable: totals tie to their components, the balance sheet balances, cash rolls forward and sign conventions stay consistent. Every mechanical flag the browser raised must be either confirmed or explicitly set aside by the audit, and anything it never mentioned is listed as still open.
A derived work of @anthropics/audit-xls, the open-source spreadsheet-audit skill from Anthropic's financial-services plugins (Apache-2.0).