audit-xls

Audit a spreadsheet for formula accuracy, errors, and common mistakes. Scopes to a selected range, a single sheet, or the entire model (including financial-model integrity checks like BS balance, cash tie-out, and logic sanity). Triggers on "audit this sheet", "check my formulas", "find formula errors", "QA this spreadsheet", "sanity check this", "debug model", "model check", "model won't balance", "something's off in my model", "model review".

Audit Spreadsheet

Audit formulas and data for accuracy and mistakes. Scope determines depth — from quick formula checks on a selection up to full financial-model integrity audits.

Step 1: Determine scope

If the user already gave a scope, use it. Otherwise ask them:

What scope do you want me to audit?

selection — just the currently selected range

sheet — the current active sheet only

model — the whole workbook, including financial-model integrity checks (BS balance, cash tie-out, roll-forwards, logic sanity)

The model scope is the deepest — use it for DCF, LBO, 3-statement, merger, comps, or any integrated financial model before sending to a client or IC.

Step 2: Formula-level checks (ALL scopes)

Run these regardless of scope:

Check	What to look for
Formula errors	`#REF!`, `#VALUE!`, `#N/A`, `#DIV/0!`, `#NAME?`
Hardcodes inside formulas	`=A1*1.05` — the `1.05` should be a cell reference
Inconsistent formulas	A formula that breaks the pattern of its neighbors in a row/column
Off-by-one ranges	`SUM`/`AVERAGE` that misses the first or last row
Pasted-over formulas	Cell that looks like a formula but is actually a hardcoded value
Circular references	Intentional or accidental
Broken cross-sheet links	References to cells that moved or were deleted
Unit/scale mismatches	Thousands mixed with millions, % stored as whole numbers
Hidden rows/tabs	Could contain overrides or stale calculations

Step 3: Model-integrity checks (MODEL scope only)

If scope is model, identify the model type (DCF / LBO / 3-statement / merger / comps / custom) and run the appropriate integrity checks below.

3a. Structural review

Check	What to look for
Input/formula separation	Are inputs clearly separated from calculations?
Color convention	Blue=input, black=formula, green=link — or whatever the model uses, applied consistently?
Tab flow	Logical order (Assumptions → IS → BS → CF → Valuation)?
Date headers	Consistent across all tabs?
Units	Consistent (thousands vs millions vs actuals)?

3b. Balance Sheet

Check	Test
BS balances	Total Assets = Total Liabilities + Equity (every period)
RE rollforward	Prior RE + Net Income − Dividends = Current RE
Goodwill/intangibles	Flow from acquisition assumptions (if M&A)

If BS doesn't balance, quantify the gap per period and trace where it breaks — nothing else matters until this is fixed.

3c. Cash Flow Statement

Check	Test
Cash tie-out	CF Ending Cash = BS Cash (every period)
CF sums	CFO + CFI + CFF = Δ Cash
D&A match	D&A on CF = D&A on IS
CapEx match	CapEx on CF matches PP&E rollforward on BS
WC changes	Signs match BS movements (ΔAR, ΔAP, ΔInventory)

3d. Income Statement

Check	Test
Revenue build	Ties to segment/product detail
Tax	Tax expense = Pre-tax income × tax rate (allow for deferred tax adj)
Share count	Ties to dilution schedule (options, converts, buybacks)

3e. Circular references

Interest → debt balance → cash → interest is a common intentional circ in LBO/3-stmt models
If intentional: verify iteration toggle exists and works
If unintentional: trace the loop and flag how to break it

3f. Logic & reasonableness

Check	Flag if
Growth rates	>100% revenue growth without explanation
Margins	Outside industry norms
Terminal value dominance	TV > ~75% of DCF EV (yellow flag)
Hockey-stick	Projections ramp unrealistically in out-years
Compounding	EBITDA compounds to absurd $ by Year 10
Edge cases	Model breaks at 0% or negative growth, negative EBITDA, leverage goes negative

3g. Model-type-specific bugs

DCF:

Discount rate applied to wrong period (mid-year vs end-of-year)
Terminal value not discounted back
WACC uses book values instead of market values
FCF includes interest expense (should be unlevered)
Tax shield double-counted

LBO:

Debt paydown doesn't match cash sweep mechanics
PIK interest not accruing to principal
Management rollover not reflected in returns
Exit multiple applied to wrong EBITDA (LTM vs NTM)
Fees/expenses not deducted from Day 1 equity

Merger:

Accretion/dilution uses wrong share count (pre- vs post-deal)
Synergies not phased in
Purchase price allocation doesn't balance
Foregone interest on cash not included
Transaction fees not in sources & uses

3-statement:

Working capital changes have wrong sign
Depreciation doesn't match PP&E schedule
Debt maturity schedule doesn't match principal payments
Dividends exceed net income without explanation

Step 4: Report

Output a findings table:

#	Sheet	Cell/Range	Severity	Category	Issue	Suggested Fix

Severity:

Critical — wrong output (BS doesn't balance, formula broken, cash doesn't tie)
Warning — risky (hardcodes, inconsistent formulas, edge-case failures)
Info — style/best-practice (color coding, layout, naming)

For model scope, prepend a summary line:

Model type: [DCF/LBO/3-stmt/...] — Overall: [Clean / Minor Issues / Major Issues] — [N] critical, [N] warnings, [N] info

Don't change anything without asking — report first, fix on request.

Notes

BS balance first — if it doesn't balance, everything downstream is suspect
Hardcoded overrides are the #1 source of silent bugs — search aggressively
Sign convention errors (positive vs negative for cash outflows) are extremely common
If the model uses VBA macros, note any macro-driven calculations that can't be audited from formulas alone