A three-way financial model — also called an integrated financial model — links a projected profit and loss statement, a projected balance sheet, and a projected cash flow statement into a single, consistent framework. When one input changes, all three statements update automatically.

This is the gold standard of financial modelling for growing businesses, and it is the format that banks, investors, and sophisticated boards expect when making major financial decisions.

Yet for many SME founders, the three-way model feels intimidating or inaccessible. It should not. In this guide I will explain what it is, why it matters, and how to build one.

Why a Three-Way Model Matters

Most business owners can produce a revenue forecast. Fewer can produce a proper P&L forecast. Almost none have a balance sheet and cash flow statement that integrates with their P&L — which means they have a fundamentally incomplete picture of their financial future.

Here is the problem: a standalone P&L forecast will tell you whether your business is profitable, but it will not tell you whether you have the cash to survive. The connection between profitability and cash is found in the balance sheet — specifically in working capital items like debtors, creditors, and inventory.

A three-way model makes that connection explicit. It forces you to think through:

When will customers actually pay you (not just when you invoice them)?
How much inventory will you need to carry at any given revenue level?
When will you pay suppliers?
What does all of this mean for your bank balance?

These are the questions that separate businesses that scale successfully from those that grow into a cash crisis.

The Structure of a Three-Way Model

Statement 1: Profit and Loss (P&L)

The P&L forecast is typically the starting point. It projects:

Revenue — by product line, segment, or channel, with volume and price assumptions explicit
Cost of goods sold / direct costs — as a function of revenue (using margin percentages or unit cost assumptions)
Gross profit and gross margin
Operating expenses — typically a mix of fixed costs (rent, base salaries) and variable costs (commissions, packaging)
EBITDA (earnings before interest, tax, depreciation, and amortisation)
Depreciation and amortisation
Interest
Tax
Net profit

The P&L is an accrual-based statement — it records revenue when earned and costs when incurred, regardless of cash timing.

Statement 2: Balance Sheet

The balance sheet is what most SME models omit, and its omission is what makes them incomplete. The balance sheet shows what the business owns (assets) and what it owes (liabilities) at a point in time.

For the purposes of a forward-looking model, the critical balance sheet items are:

Working capital:

Accounts receivable — projected based on revenue and debtor days assumption
Inventory — projected based on COGS and inventory days assumption
Accounts payable — projected based on COGS/purchases and creditor days assumption

Fixed assets:

Opening balance plus capital expenditure minus depreciation

Debt:

Opening balance plus new drawdowns minus repayments

Equity:

Opening balance plus net profit minus dividends/drawings

Statement 3: Cash Flow Statement

The cash flow statement is derived from the P&L and balance sheet movements. It shows actual cash generated or consumed during the period.

The key components are:

Operating cash flow:

Net profit
Add back: depreciation (non-cash)
Adjust for: changes in working capital (increase in debtors = cash outflow; increase in creditors = cash inflow)

Investing cash flow:

Capital expenditure (outflow)
Asset disposals (inflow)

Financing cash flow:

New debt drawdowns (inflow)
Loan repayments (outflow)
Equity injections (inflow)
Dividends/drawings (outflow)

Net movement in cash = Opening cash + Operating CF + Investing CF + Financing CF

How the Three Statements Connect

The elegance of a three-way model is in the connections:

P&L to balance sheet: Net profit flows into retained earnings in equity. Depreciation on the P&L reduces fixed asset values on the balance sheet. Tax on the P&L creates a tax payable liability.
Balance sheet to cash flow: Changes in working capital balances drive operating cash flow. Capital expenditure drives the investing cash flow section. Debt movements drive the financing section.
Cash flow to balance sheet: The closing cash balance on the cash flow statement must equal the cash line on the balance sheet. If it does not, the model has an error — and this built-in check is one of the model's greatest virtues.

When the model balances, you can trust it. When it does not, you know something is wrong.

Building the Model: Practical Steps

Step 1: Define Your Time Horizon and Granularity

For most SMEs, a monthly model over 12–24 months is appropriate. Annual models miss the cash flow timing detail that matters most for working capital planning.

Step 2: Build the Revenue Model

Start with your revenue assumptions. Be explicit about drivers: number of customers, average order value, sales volume. Avoid the temptation to build a single "revenue" line — the more disaggregated the better.

Step 3: Build the Cost Model

Separate fixed costs (which do not change with revenue) from variable costs (which do). This distinction matters for scenario analysis.

Step 4: Calculate Working Capital Assumptions

Set your debtor days (how long customers take to pay), inventory days (how much stock you carry), and creditor days (how long you take to pay suppliers). These three assumptions drive your working capital balances and therefore your cash position.

Step 5: Add Capex and Debt

Include any planned capital expenditure and the associated depreciation. Add opening debt balances and model repayments according to loan terms.

Step 6: Link the Three Statements and Check the Balance

Build the connections described above. The acid test is whether the balance sheet balances (assets = liabilities + equity) and whether the closing cash on the cash flow statement equals the cash on the balance sheet.

Using the Model

Once built, a three-way model becomes a powerful planning tool:

Scenario analysis — model best case, base case, and downside. What happens to cash if revenue is 20% below forecast?
Funding analysis — how much funding do you need, and when? The cash flow statement tells you precisely.
Covenant analysis — if you have bank debt with financial covenants, model whether you will breach them under different scenarios.
Investor presentations — a credible three-way model is a prerequisite for serious investor or lender conversations.

Building a three-way model takes time and attention to detail. But once it exists, it becomes the most powerful financial tool in your arsenal. Every significant decision — a new hire, a capital investment, a pricing change — can be tested through the model before you commit real money.

How to Build a Three-Way Financial Model