How to Build a Startup Financial Model for Fundraising and Runway

A useful startup financial model answers a small number of important questions: how cash changes, which assumptions drive the outcome, how much funding is needed, and what the company can achieve before the next financing point.

It should be understandable to the founders who use it. A complicated workbook is not a better model if nobody can explain the logic.

What should a startup financial model include?

• an assumptions section with clear inputs;

• a revenue model based on the real commercial drivers;

• a hiring plan with start dates, salaries and employer costs;

• operating costs, capital spending and major commitments;

• integrated profit and loss, cash flow and balance sheet;

• monthly runway and funding requirements;

• base, downside and upside scenarios.

How should revenue be modelled?

Use the drivers that management can explain and monitor. A subscription business may model leads, conversion, customer starts, churn and average revenue. A deep-tech business may model development milestones, pilots, contracts and delivery capacity.

A simple driver model is usually more credible than a smooth percentage growth curve. It makes it possible to explain why the number changes and what evidence would support it.

How should founders model hiring?

Build the plan person by person or role by role, with realistic start dates and full employer cost. Include recruitment fees, benefits, equipment and the delay between approving a role and the person becoming productive.

Hiring is often the largest controllable cost in an early-stage company. A scenario that moves three hires by one quarter can be more useful than changing every expense by 10%.

How do you calculate runway?

Runway is not simply current cash divided by last month’s burn. Use a month-by-month cash forecast that includes payroll, taxes, annual payments, committed projects, customer receipts and the timing of the proposed round.

The model should show when the company reaches a minimum cash buffer, not only the month in which cash becomes negative.

What do investors expect from the model?

Investors normally want the model to match the pitch deck and use of funds. They will test the main assumptions, the relationship between capital and milestones, and what happens if revenue or hiring moves more slowly.

The model does not need to predict the future perfectly. It needs to show that the team understands the economic drivers, cash consequences and decisions available.

Common modelling mistakes

• hard-coding figures throughout the workbook;

• using growth percentages that are not connected to customers or capacity;

• forgetting VAT, payroll taxes, payment timing or annual costs;

• showing one optimistic case with no downside;

• failing to reconcile the opening position to the accounts;

• building a model that only the adviser can operate.

Frequently asked questions

How many years should the model cover?

Monthly detail for 24 to 36 months is often useful, with less detailed later years if needed. The right horizon depends on the funding and business cycle.

Should the downside case assume zero revenue?

Not always. A useful downside changes the assumptions most likely to move, such as sales timing, churn, hiring or a smaller round.

Can an existing model be repaired?

Yes. Start by checking the opening balances, core logic, assumptions and cash flow before adding more detail.

See our financial modelling service, or use our monthly or quarterly reporting and planning package to connect management accounts, budget comparisons and cash forecasts.

Important: This article is general information, not financial or investment advice.