How to build a financial model for a small business

What a financial model is for

A model answers practical questions: will the business pay for itself, when will it break even, how much money do you need to launch, and what happens if sales are 30% lower than planned. Banks and investors ask for it, but the main reader is you.

A good model is short. Twenty well-chosen lines beat a spreadsheet with forty tabs that nobody can check.

Step 1. Pick the horizon and the start month

For a new business plan 24–36 months by month. Shorter horizons hide the payback, longer ones become guesswork. Start from the month you begin spending money, not from the opening day: rent, deposits and salaries usually start earlier.

Step 2. Build revenue from drivers

Do not type “revenue: 20,000”. Break it into the numbers you can check and influence:

• Retail and food: average ticket × number of sales.
• Services: visits or hours × price, limited by capacity.
• Subscriptions: active customers × price, where the base grows with new customers and shrinks with churn.
• Online sales: ad budget ÷ cost per lead × conversion × average order.

Add a ramp-up: almost no business reaches full capacity in the first month.

Step 3. Split costs into variable and fixed

Variable costs grow with sales: cost of goods, payment and marketplace fees, commissions. Put them as a percentage of revenue or per unit.

Fixed costs do not depend on sales: rent, software, accounting, insurance. Put them as monthly amounts and add inflation if the horizon is longer than a year.

Step 4. Staff with the real cost of a salary

A salary is not the full cost of an employee. Payroll taxes and contributions add a significant share on top. Plan each role with a start month: hiring everyone in month one is the most common reason a startup runs out of money early.

Step 5. Investments, loans and depreciation

Fit-out, equipment and a launch budget are one-off payments. They leave your account in one month but serve for years, so profit spreads them through depreciation while cash takes the hit at once.

A loan brings cash in, but the repayments of principal do not reduce profit. That is why a business can show profit and still have no money.

Step 6. Taxes

Choose the tax base that applies to you: revenue, profit or a fixed amount. Taxes on profit are usually accrued from the start of the year, so a loss in spring lowers the tax in summer. Do not forget to pay yourself: owner payouts are not an expense in profit, but they leave the account.

Step 7. Read the cash flow, not only profit

Once revenue and costs are in, look at three numbers: the month of break-even, the payback month and the lowest cash balance. The lowest point is how much money you need before you start, plus a reserve.

Step 8. Scenarios and a sanity check

Make a pessimistic scenario: sales 30% lower, costs 10% higher. If the business survives it, the plan is robust. Then check the model for typical errors: growth of 20% a month means ninefold in a year, margins far above competitors, forgotten taxes or payroll costs.

Spreadsheet or a dedicated tool

A spreadsheet is flexible, but every formula is a place for a mistake, and someone else cannot quickly check where a total comes from. FinModel builds the same model from blocks with plain fields, keeps profit and cash separately, explains every number in words and warns about cash gaps. The AI assistant can assemble the first version from a description of your business and check the numbers against your market.

Try it free for 7 days