You build it from the real drivers — the size of the market, the unit economics, and the operating costs, assembled into a cashflow — and you treat the inputs you can't know yet as ranges instead of single guesses. Growth Forge® Software helps you do this with guided tools, so you don't need spreadsheet wizardry or a finance background: you bring the basic logic and assumptions about your business, and it handles the modeling and the math — walking you through market sizing, unit economics, and expenses, carrying your uncertain inputs as ranges, and showing you the range of outcomes your idea could produce rather than one number that looks precise and isn't. Built on BRI Associates' decades of practitioner experience in corporate innovation and new business development, it's free to start.
For a new business, the financial model is the thing investors ask for and founders put off — because almost every input is an assumption, and the ones that matter most are the ones you're least sure of. Build it on a blank spreadsheet and you hit two walls: it takes real Excel and finance skill just to construct something credible, and the moment you change a price, a segment, or the timing, you're rebuilding formulas — even though exploring exactly those changes is the whole point. And because a spreadsheet pushes every guess into a single cell, you end up with a five-year projection that reads to the dollar but rests on a hunch about adoption. The goal isn't a precise forecast. It's a defensible characterization of the opportunity — sound logic, plus insight into which assumptions are consequential enough to prioritize where you spend your evidence-gathering effort.
A model you can make a decision on — or raise on — needs a few things, none of which require you to be a finance expert. It should be built from the real drivers (market size, unit economics, and costs adding up to a cashflow, not a top-down number reverse-engineered to look good). It should be honest about uncertainty, carrying the values you can't know yet as ranges and making clear which assumptions the answer actually depends on. It should be tied to your strategy, so when you change a choice — a different customer, a new price, a staged launch — the numbers move with it instead of breaking. And it should match its depth to the decision: a quick back-of-the-envelope read when you're just exploring, a fuller model when real money is on the line.
In Growth Forge the financials are one dimension of your strategy — the Financial Logic of your Strategy Hypothesis Model — not a separate workbook you have to build. You bring the basic logic and the key assumptions about your business; Growth Forge does the modeling and the math. Guided tools handle the construction: Market Sizing quantifies the opportunity through segment-based conversion modeling, Unit Economics models the cost and profitability of a single unit, and Expense Planning captures fixed and variable costs to produce a full cashflow forecast — and because they share one underlying model, an input you enter in one is available in the others. You enter the values you can't know yet as ranges, and Growth Forge runs them through Monte Carlo simulation to show a distribution of outcomes instead of a single deterministic line. The Assumptions Manager keeps track of every assumption and ranks it by how uncertain and how consequential it is, so the few you should actually go test stand out. You can start with a quick low-fidelity pass and add depth as the decision gets bigger — all without Excel mastery or a strategic-finance specialist on the team.
A spreadsheet can do the arithmetic, but it asks you to bring the modeling skill, nudges every guess into a single number, and breaks when the strategy changes. A downloadable financial-model template gives you a structure but no guidance — you're still filling it in alone and hoping you set it up right. An AI chatbot can sketch a projection or poke at your assumptions, and AI genuinely helps — Growth Forge has AI assistants built in, too. What a standalone chatbot doesn't keep is a persistent, structured model that tracks which inputs you've validated and stays tied to your strategy. Growth Forge pairs that structure with AI: the guided, living version, a bit like TurboTax but for the economics of a new business, that's honest about uncertainty and moves with your strategy instead of against it.
What you get isn't a spreadsheet — it's a credible economic case you can defend to a co-founder, an investor, or your own gut, with the range of outcomes visible and the riskiest assumptions flagged so you know exactly where the idea is most exposed before you put real money behind it. That's the difference between a number you hope is right and a case you can actually stand behind.
Every Growth Forge trial comes pre-loaded with a worked example, modeled end to end, so you can see a full new-business financial case — ranges and all — before you build your own. It's the fastest way to see what guided modeling looks like without starting from a blank sheet.
Start a free 14-day trial and open the pre-loaded sample to see a finished model, then build the economic case for your own idea — guided, with uncertainty handled as ranges. If you'd like an expert to orient you, you can book a live walkthrough. You can also sketch the strategy first on the free Strategy Hypothesis Canvas and bring it in. Build a financial case you can defend, and find out where it's most exposed before you commit real money to it.
You use guided tools that help you build the model from the real drivers — you bring the logic and assumptions, and Growth Forge® handles the modeling and math. It walks you through market sizing, unit economics, and expenses, assembles them into a cashflow, carries the values you can't know yet as ranges, and runs Monte Carlo simulation to show a range of outcomes — so you get a credible model without spreadsheet skills or a finance background.
Right — and the rigor is built in. Growth Forge encodes the financial-modeling discipline BRI developed over decades of practitioner experience and uses with Fortune 500 clients, so a founder or project lead can produce credible market sizing, unit economics, and cashflow without Excel mastery or a strategic-finance specialist. You bring the judgment about your business; the platform carries the rigor.
You enter uncertain values as ranges rather than single guesses, and Growth Forge runs them through Monte Carlo simulation to produce a distribution of outcomes instead of one false-precise number. The Assumptions Manager then tracks every assumption and ranks it by how uncertain and how consequential it is, so you can see which few are worth going out and testing first.
A spreadsheet makes you bring the modeling skill and breaks when your strategy changes; a template gives you boxes but no guidance and no way to represent uncertainty. Growth Forge guides the build, carries uncertainty as ranges, keeps the model tied to your strategy so it moves when you change a choice, and keeps it as a living model you refine — not a one-time file.
Yes. You can start a free 14-day Growth Forge trial with a sample model pre-loaded so you have a finished example to learn from on day one, and you can sketch your strategy first on the free Strategy Hypothesis Canvas.
Founders, startup teams, and innovation project leads who need a believable financial case for a new product or new business — and who would rather not build it from scratch in a spreadsheet or hire a finance specialist to do it.
