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INHERITED WORKBOOK AUDIT · EXPLAIN THIS WORKBOOK

An inherited workbook audit for the model someone left you.

You opened a 14-tab Excel file from someone who left the team six months ago. You're supposed to use it to make a decision this week. An inherited workbook audit gives you the full map: every formula pattern, every external link, every hardcoded assumption, every hidden risk — plus a plain-English summary of what the model actually does.

Audit an inherited file freeSee pricing →

Free tier — 30 audits/month — no card required.

Inheriting a spreadsheet is inheriting a black box

Someone built it. They left. The documentation, if it existed, is out of date. You're supposed to use the workbook to make a call — and you have no idea where the assumptions live, what gets calculated from what, or which numbers are typed in versus derived.

Click-by-click discovery takes hours and still misses the silent risks. An inherited workbook audit produces the map in seconds: structural overview, formula inventory, hardcoded-value inventory, external link inventory, plus a natural-language summary of what the workbook is for and how it's organized.

How the inherited-workbook audit runs

  1. 1

    1. Upload

    Drop the file you inherited. .xlsx, .xlsm, or pick from Google Drive. Up to 50 MB on Pro.

  2. 2

    2. Structural map

    Sheet-by-sheet inventory: row count, column count, hidden state, formula density, last-modified date, and a short description of what each sheet appears to contain.

  3. 3

    3. Risk inventory

    Every formula error, every hardcoded value buried in a formula, every external link, every circular reference, every unusual function — listed with location and explanation.

  4. 4

    4. Plain-English summary

    An AI-written narrative that reads the workbook structure and explains, in 3-5 paragraphs, what the workbook seems to be for, how data flows through it, and where the load-bearing assumptions live.

What the inherited-workbook audit surfaces

Everything a careful spreadsheet inheritor would check by hand — except this version runs in under a minute and doesn't skip the boring parts.

  • Sheet-by-sheet structural map

    Visible sheets, hidden sheets, very-hidden sheets, and their relative size. Useful first orientation when the workbook has more than ~5 tabs.

  • Formula density per sheet

    Which sheets are mostly typed-in inputs vs. mostly derived calculations. Tells you where to look for assumptions (input-heavy) vs. logic (formula-heavy).

  • Hardcoded constants and their location

    Tax rates, FX rates, threshold values, fudge factors. Listed by cell so you can decide which to centralize into a named range and which to leave as-is.

  • External references (in or out of date)

    Every link to another workbook, OneDrive file, or Google Sheet. The first thing that breaks when you move the file to a new folder.

  • Named ranges and what they reference

    Often the load-bearing labels of an inherited model — "USDRate", "DiscountFactor", "AssumedGrowth". Listed with definitions so you can audit them.

  • Formula error inventory

    Every #REF!, #DIV/0!, #N/A — including the silent ones where the formula returns a value but the lookup is pointing somewhere wrong.

  • Workbook narrative summary

    AI-written, 3-5 paragraphs explaining what the workbook seems to do, how data flows, and where the critical assumptions live. Not a substitute for the original author, but a useful first orientation.

  • Macro and Apps Script inventory

    For .xlsm files: every VBA module and macro is listed (not executed). For Google Sheets: any attached Apps Script triggers. Tells you what runs automatically.

Frequently asked questions

Will the audit explain what the workbook actually does?

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Yes — via the AI-written narrative summary. It reads the workbook structure (sheet names, column headers, formula patterns) and produces a plain-English description of what the workbook seems to be for and how the calculations flow. It's a first-pass orientation, not a replacement for talking to the original author — but useful when the original author isn't available.

Can I run this on a workbook I don't fully understand?

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That's exactly the use case. The audit surfaces every formula, every assumption, every external reference, every error — without you needing to know where to look. By the end, you have the map of the workbook even if you didn't build it.

Does it work on .xlsm files with VBA macros?

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Yes — the audit reads the workbook content and lists every VBA module by name with its line count. We don't execute the macros (security boundary), so if the workbook's logic depends on macro runtime evaluation, run the macros in Excel first to produce the calculated state, then audit. The audit then catches the calculated values plus the macro inventory.

Is the AI summary trustworthy?

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It's a useful first orientation, not a substitute for human review. The summary identifies what the workbook seems to do based on structure and naming. For high-stakes models (board decks, regulatory filings, audit submissions), confirm the summary against the actual calculations before relying on it.

Can I share the audit output with a colleague?

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Yes. Download the annotated workbook (every issue as a cell comment) and the audit report (.xlsx). Send both to whoever needs to understand the inherited model. Pro Plus adds multi-viewer sharing — invite up to 3 read-only reviewers per run.

Further reading

Deep-dives from the SaferSheets blog

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