The Number One Tool Early Stage Founders Overlook
The minimum financial model every seed-stage founder needs,
With a16z speedrun SR006 kicking off live in San Francisco this week, we’ll be trying something new and shipping the newsletter to your inbox twice a week for the duration of the program.
Our first double-feature is a guest essay from a16z speedrun investing partner Emily Bennet with pro tips for early stage founders thinking about how to model financials.
“We’re Too Early for a Financial Model.”
I hear this constantly, often from pre-seed or seed founders with the most impressive resumes. They have run scaled teams and built products used by millions, yet assume the early stage is too uncertain to justify time in Excel. Maybe you feel the same.
The logic sounds reasonable. Customers are still forming, pricing is provisional, and growth channels are unproven. Any model you build now will be wrong in months, perhaps weeks. You don’t want to create false precision or lose credibility with investors. So financial modeling gets pushed to later, once the business feels more “real.”
That intuition is understandable. I believe it is also wrong.
In my career as a venture investor, one of the strongest predictors of failure I have seen is a refusal to think structurally about an uncertain future. And one of the best ways to structure your view of the future is to build a financial model.
Here is why.
Your Fastest Way to Learn Is Through Testing
One of the most consistent patterns I’ve observed in startup failure is a failure to learn fast enough. Companies rarely fail because their initial assumptions are wrong. They die because they stay wrong for too long.
Research on forecasting shows that people are poor at predicting outcomes under uncertainty, but better at improving decisions when assumptions are made explicit and updated as new information arrives. These people don’t have some magical predictive powers. Their gift comes from structured iterations of their world view.
That is exactly the role a financial model should play at the pre-seed and seed stages. The goal is not to produce an accurate forecast, but to externalize beliefs in a way that makes them testable.
Building a model forces clarity about what must be true for the business to work. When reality diverges, the gap becomes legible. A CAC that lands at $120 instead of $40 is no longer a vague sense that growth is hard. It is a concrete signal about where learning is required.
Surprise is the mind killer
One of the biggest dangers of skipping a financial model is being surprised.
I have worked with many early-stage teams who were shocked when runway disappeared faster than expected, when they lacked the metrics needed to raise the next round at a reasonable valuation, or when their business could not sustain itself economically. A model does not eliminate these risks, but it makes them visible early enough to act.
Financial models accelerate learning in three ways.
They surface the real constraint, quickly revealing whether retention, pricing, sales efficiency, or burn rate is the bottleneck.
They create tight feedback loops. When reality diverges from the model, you immediately see where and by how much, turning gaps into concrete questions.
They enable intentional pivots by clarifying which assumptions broke and why.
In practice, the best founders treat their model as a living document. They update it regularly, use it to set near-term goals, and communicate progress clearly. You do not need a three-statement, GAAP-perfect model. A single spreadsheet with key assumptions, burn, runway, and a few scenarios is enough, as long as the logic is clear and evolves.
The Three Things You Actually Need to Track
Seed-stage startups should focus on three key tiers of signals that answer the question: can this company survive, make progress, and ultimately work as a business?
Tier 1: Financial Viability
This is the baseline. You need a clear view of cash in, cash out, burn, and runway over the next 12 months. The goal is to eliminate surprises about survival.
Tier 2: Structural Goal-Setting
This is your OKR layer. Which outcomes signal real progress toward product-market fit? What must be true of the business for you to believe you are building something users genuinely want?
For a consumer company that is not yet monetizing, or a very early B2B company, the P&L may show only outflows. You still need a quantified north star. For example: “We will grow weekly active users by X percent month over month while maintaining Y percent retention in our core cohort.”
That metric matters less as an external narrative and more as an internal truth. It becomes the scorecard for whether the product is resonating with users. Consistent goal tracking also creates a baseline for comparison, allowing you to benchmark against similar companies and distinguish surface-level activity from real, competitive traction.
Tier 3: Business Model Efficiency
Finally, you need to pressure-test whether the business model can work at all. What does steady-state unit economics look like? Is there a path to durable, scalable ROI?
You will likely not know true LTV at seed, and that is okay. What you need is a defensible hypothesis. “We believe LTV will be roughly $500 based on comparable products, which implies CAC must stay below $150.” From there, you track early indicators such as cohort retention, payback, and expansion to see whether reality is converging toward that hypothesis or drifting away from it.
Where to start
Still, I know you have a million things to do. So, I wanted to make this as easy as possible. To help I created three interactive trackers to kickstart deeper visibility into the early metrics that matter:
Financial Viability Tracker - A straightforward cash tracking tool that answers the fundamental question: “Will we still have money at the end of the year?” It includes:
Revenue, fixed, and variable cost inputs
Current cash, monthly burn, and runway calculation
Structural Goal Setting Tracker - An OKR-focused tool that helps founders work backward from their next fundraise. It includes:
North star metric tracking with growth projections
Multiple objectives (OKRs) with progress tracking
Unit Economics Tracker: A tool for pressure-testing business model viability. It includes:
LTV:CAC ratio calculations
Cohort retention tracking
So yes, don’t reject the push to build a model. And use this as a starting point! You’ll have a much better grasp of your business as it naturally evolves.
Have other questions for Emily? Reply and let us know. And for more weekly dives into the world of early stage startups, subscribe below.
Hi, I tried to download both but the contentis blocked by the owner :(
Great article, Emily.
One thing I'd emphasize is that the output of the model is relatively unimportant ; as you said, it will be wrong in a few weeks. What matters is regularly revisiting the assumptions with actuals and then revising thinking and activities.
Of course, that assumes you are regularly and systematically capturing the base values. That's the part I often see people miss and, by doing so, much of the value of the model is lost.