Startup Financial Metrics Every Founder Should Know Cold

TL;DR: An investor can tell in about 90 seconds whether you run your business or just work inside it. They ask for a few numbers and watch whether you answer instantly or reach for a spreadsheet. Know these four startup financial metrics cold: your runway, your gross margin, your CAC payback, and whether you are default alive or default dead.

The four numbers investors test you on

You do not need a finance degree to pass the test. You need to have looked at your own numbers recently enough to recite them.

The founders who raise fastest are rarely the ones with the most polished story. They are the ones who never get caught not knowing their own company. When an investor asks a basic number and you answer without flinching, you signal control. When you reach for a spreadsheet, you signal the opposite, and the rest of the conversation gets harder.

Here are the four startup financial metrics that matter most. Look at them once, then keep looking.

1. How to calculate runway

Runway is cash in the bank divided by your net monthly burn.

If you have $600,000 and you burn $50,000 a month, you have 12 months of runway. This number determines every other decision you make: when to hire, when to raise, how aggressively to spend. "I think it is around a year" is not an acceptable answer about your own company.

2. What is a good gross margin?

Gross margin is revenue minus the direct cost of delivering your product, expressed as a percentage.

A SaaS business should usually be high, often 70 percent or more. A services business that scales with headcount is usually much lower. Gross margin is the difference between a business that gets more profitable as it grows and one that simply gets bigger. If you do not know yours, you do not yet know whether you have a real business or an expensive hobby. A weak gross margin also drags down your burn multiple as you scale.

3. What is a good CAC payback period?

CAC payback is how many months of a customer's revenue it takes to earn back what you spent to acquire them.

Under 12 months is healthy for most startups. If it takes 30 months to recover what you spent winning a customer, you do not have a growth engine, you have a leak. CAC payback is the fastest way to tell whether spending more on growth will compound or just drain the bank.

4. Default alive or default dead

This one comes from Paul Graham, and it is the most important question on the list.

If you keep your current growth rate and your current spending, and you never raise another dollar, do you reach profitability before the money runs out?

If yes, you are default alive. If no, you are default dead.

Most founders do not actually know their answer, because they assume the next round will come and never run the math on what happens if it does not. That assumption is what turns a fixable problem into a fatal one. By the time you discover you are default dead, your options have already narrowed.

The reason it matters even if you fully intend to raise: a default-alive founder raises from strength. They can walk from a bad term sheet and wait for the right investor. A default-dead founder raises from need, and everyone across the table can sense it.

How to use these

Write all four on a single sticky note today. Update them monthly. That is the entire discipline.

If your default-alive math comes back as dead, you have two levers: grow faster or spend less. Pick the one you can actually move in the next 90 days, and move it. And reframe the goal of raising. The point of a raise is to accelerate a business that already works, not to rescue one that is sinking.

Frequently asked questions

How do you calculate runway? Divide your cash in the bank by your net monthly burn. With $600,000 in the bank and $50,000 of monthly burn, your runway is 12 months.

What is a good gross margin for a SaaS startup? Software businesses typically aim for 70 percent or higher. Services businesses that scale with headcount usually run much lower, which is normal for that model.

What is a good CAC payback period? Under 12 months is healthy for most startups. The longer the payback, the more cash is tied up before each customer becomes profitable.

What does "default alive or default dead" mean? It is Paul Graham's question: at your current growth and spending, and without raising again, do you reach profitability before the cash runs out? If yes, you are default alive. If no, you are default dead.

Where this fits

These four numbers pair with your burn multiple, the single cleanest read on capital efficiency. To pressure-test how well you read your own books, take the free accounting literacy quiz, and if you are weighing a raise, the VC readiness quiz gives you an honest read on whether you are fundable yet.

Want help

Getting these numbers right, keeping them current, and walking into any investor conversation able to answer cold is most of what we do at Startup Geek. Book a free consultation. No pitch.