Due Diligence in Excel: Structure Before the Deal

The time between letter of intent and signing is crowded with competing demands - legal reviews, site visits, management meetings, and data requests arriving in waves. Without a structured workbook, critical questions slip through the cracks and valuation assumptions go untested.

A purpose-built due diligence workbook in Excel gives you a single source of truth for the entire deal review process. This guide walks through building one sheet by sheet, with formulas and structure an SME buyer could actually use.

If you are new to the acquisition process, start with our overview of buying a small business and the valuation framework that underpins the numbers in this workbook.

Sheet 1: The Due Diligence Process Map

Rename the first sheet to "Process Map". This is your deal navigation tool. It keeps the team aligned on what has been done, what is pending, and who owns each workstream.

Columns to build

• Work stream (financial, legal, commercial, operational, management)
• Task description
• Responsible party
• Start date and target completion date
• Status (not started, in progress, completed, blocked)
• Document reference
• Key findings summary

Conditional formatting

Apply three-colour conditional formatting to the status column: RED for blocked items, AMBER for in progress, GREEN for completed. Use a helper column to flag overdue tasks:

=IF(AND(TODAY()>D2, E2<>"completed"), "OVERDUE", "ON TRACK")

Where D2 is the target date and E2 is the status cell.

Add a simple Gantt-style bar using WEEKDAY and conditional formatting across 12 monthly columns. This provides a one-glance view of whether the deal is on schedule.

Sheet 2: Financial Data Tab

Rename the second sheet to "Financial Data". This is where you load three years of historical financial statements and the latest interim period. Structure matters because every other sheet pulls from this tab.

Profit and Loss

Build a stacked layout with these rows:

• Revenue (segmented by product line or service type)
• Cost of goods sold
• Gross profit and gross margin percentage
• Operating expenses (rent, wages, marketing, administration, professional fees)
• EBITDA
• Adjustments (normalisation items: owner salary above market, one-off costs, non-recurring revenue)
• Normalised EBITDA
• Depreciation and amortisation, EBIT, interest, net profit

Key formulas:

Gross Margin % = Gross Profit / Revenue
EBITDA Margin % = EBITDA / Revenue

Add a "Quality of Earnings Ratio":

= Cash from Operations / Net Profit After Tax

A ratio consistently below 0.8 suggests earnings quality issues. Revenue may be recognised before cash is collected, or expenses are being deferred.

Balance Sheet

Include cash, trade debtors, inventory, fixed assets, intangible assets, trade creditors, accrued expenses, short-term and long-term debt, and shareholder equity.

Calculate working capital:

= Trade Debtors + Inventory - Trade Creditors

Track working capital as a percentage of revenue. A rising ratio means the business needs more capital to generate each dollar of sales.

Cash Flow Statement

Reconstruct from the P&L and balance sheet:

Cash from Operations = Net Profit + Depreciation + Amortisation - Increase in Debtors - Increase in Inventory + Increase in Creditors

Compare operating cash flow to EBITDA. A large and persistent gap signals aggressive accrual accounting.

For a deeper look at financial model building, see capital raising financial models.

Sheet 3: Valuation Cross-Check

Rename the third sheet to "Valuation Cross-Check". Run three methods side by side to triangulate on a fair price.

Method 1: Earnings Multiple Approach

Enterprise Value = Normalised EBITDA x Industry Multiple
Equity Value = Enterprise Value - Net Debt

Reference normalised EBITDA from your Financial Data sheet. Use a conservative multiple at the low end of the industry range and an optimistic multiple at the high end.

Build a sensitivity table using Excel's Data Table feature: set EBITDA multiple (2.0x to 6.0x) as the column input and normalised EBITDA (minus 10% to plus 10% of base case) as the row input. The resulting grid shows how valuation changes with each assumption.

Method 2: Discounted Cash Flow

Build a five-year projection with revenue growth, EBITDA margin, tax, capex, and working capital inputs.

Terminal value:

= FCF_Year_5 x (1 + Terminal_Growth_Rate) / (WACC - Terminal_Growth_Rate)

Discount using XNPV:

= XNPV(WACC, Total_Cash_Flow_Range, Date_Range)

The WACC range for most SME acquisitions is 12-18%. Run sensitivity on this range.

Method 3: Asset-Based Approach

Net Asset Value = Total Assets (at market value) - Total Liabilities

This gives the floor price. The negotiation happens between the asset floor and the income-based ceiling.

For a complete walkthrough of valuation methods, see our SME business valuation Excel model.

Sheet 4: Synergy and Integration Cost Estimator

Rename to "Synergy & Costs". This sheet separates hype from numbers. Synergies are easy to overestimate and integration costs are easy to underestimate.

Revenue synergies

• Cross-selling to existing customer base
• Geographic expansion using acquired distribution channels
• Product bundling opportunities
• Pricing optimisation post-acquisition

Estimate a conservative and an optimistic case for each. Use the conservative case in your base valuation.

Cost synergies

• Headcount reduction in redundant roles
• Supplier consolidation and volume discounts
• Shared premises and overhead
• Technology platform consolidation
• Marketing spend efficiency

Integration costs

• Redundancy payments
• System migration and IT integration
• Brand and signage changes
• Legal and restructuring advisory
• Customer contract renegotiation
• Working capital injection

Net synergy is calculated as:

= (Revenue_Synergies_Conservative + Cost_Synergies_Conservative) - Integration_Costs

Include a sensitivity column showing the impact if synergies are delayed by 12 months or integration costs run 30% above estimate.

Sheet 5: Risk and Red Flag Tracker

Rename to "Red Flag Tracker". Every deal has issues. The question is whether you know about them and have a plan to address them.

Register columns

Built-in alerts

Use a formula to flag critical items:

= IF(AND(D2="High", F2="Yes"), "CRITICAL - REVIEW BEFORE SIGNING", "Monitor")

Where D2 is the probability column and F2 is the deal breaker column.

Add a summary cell at the top:

= COUNTIF(G:G, "Open")

This tells you how many unresolved items remain. The deal should not proceed to signing with open deal breaker items.

Add a hyperlink column to reference source documents:

= HYPERLINK("filepath", "Evidence Document")

This turns your workbook into a data room directory.

Making the Workbook Deal-Ready

Before presenting this workbook to your deal team or investment committee, take these final steps.

Input validation

Use Excel's Data Validation tool on every assumption cell. Set reasonable minimum and maximum ranges. A mistyped decimal in a valuation model can swing the purchase price by hundreds of thousands.

Version control

Add a hidden sheet called "Version Log" with columns for version number, date, author, and change description. Every time you update an assumption, log it. This protects you during negotiations when someone questions which numbers are in the model.

Print-ready summary

Create a dashboard sheet that pulls key metrics from every tab: deal name and date, valuation range from the Valuation Cross-Check sheet, number of open red flags, net synergy estimate, and implied purchase price range. Use simple cell references to build this dashboard. It becomes the one-page executive summary for the deal.

Further Reading

For a complete overview of this topic, see the Financial Modelling in Excel: The Complete Guide for Australian Businesses (2026).

Frequently Asked Questions

What sheets should a due diligence workbook include?

A practical due diligence workbook should include at least five core sheets: a due diligence process map, a financial data tab with three years of P&L, balance sheet, and cash flow statements, a valuation cross-check tab comparing DCF, multiple, and asset-based approaches, a synergy and integration cost tab, and a risk and red flag tracker. Optionally, add a sensitivity analysis sheet for key deal variables.

How do I do a quick DCF valuation in Excel for an acquisition?

Use the XNPV function for accuracy: =XNPV(discount_rate, cash_flow_range, date_range). Forecast free cash flow for five years. Calculate terminal value using the perpetuity growth formula: final year FCF times (1 plus long-term growth rate) divided by (WACC minus growth rate). The terminal value typically represents 60-80% of total enterprise value. Always run sensitivity on WACC and terminal growth rate.

What financial red flags should I look for during due diligence?

Key red flags include: revenue growing faster than cash from operations (aggressive revenue recognition), declining gross margins year over year, EBITDA adjustments exceeding 20% of reported EBITDA, unusually high working capital requirements, customer concentration above 30% from a single client, recurring related-party transactions, frequent auditor changes, and tax payable growing slower than profit (potential aggressive tax positions).

How do I track risks in a due diligence workbook?

Build a red flag register with columns for risk description, financial impact estimate, probability (high/medium/low), source document reference, mitigation strategy, deal breaker flag, and status (open/addressed/waived). Colour code cells: red for unresolved deal breakers, amber for items requiring further investigation, green for cleared items. This register becomes the basis for your final due diligence report.

What is the correct structure for a due diligence data room in Excel?

A well-structured data room workbook has a summary dashboard as the cover sheet, a process map showing the deal timeline and responsible parties, separate data sheets for financials (P&L, balance sheet, cash flow), a valuation work sheet, a synergy estimator, a risk register, and a document checklist. Each sheet should have a consistent header with version number, date, and confidentiality notice.

Start Building Your Workbook

The workbook described here takes a few hours to build but saves days of confusion. Each sheet serves a specific purpose: the Process Map keeps the team on track, the Financial Data tab provides clean inputs, the Valuation Cross-Check prevents overpayment, the Synergy & Costs sheet tests the deal thesis, and the Red Flag Tracker ensures nothing is buried.

Downloading a template is less useful than building your own. The act of constructing each formula forces you to understand the relationship between revenue and working capital, between EBITDA multiple and terminal value, between a red flag and a deal breaker. That understanding is the real value.

Start with the Process Map. Add the Financial Data sheet. Build each valuation method one formula at a time. By the time you finish, you will know the target business better than most investment bankers would in twice the time.