How to calculate your real runway

You raised money to build the product, hire the team, and prove something investors will fund again. You're probably spending more than you bring in. That's part of the plan.

The question is whether your cash lasts long enough to deliver that proof and close the next round.

A founder with $3 million in the bank and $150,000 of monthly burn can say, “We have 20 months.” Add the hires already in the plan, a slower sales ramp, and the time needed to fundraise, and that answer changes fast.

Here's how to calculate runway you can actually use to make those decisions.

Start with the quick calculation

Available cash ÷ monthly net cash burn = estimated months of runway

Use cash you can access and spend. Exclude restricted funds and financing that hasn’t arrived. Cash earmarked for hiring or other planned spending still counts; include those payments in the forecast when they’re due.

Net cash burn is cash paid out minus cash collected from operations. If you spend $200,000 and collect $50,000, your net burn is $150,000. Equity raised isn't revenue and doesn't reduce operating burn.

That calculation is a useful snapshot. It assumes the burn rate stays roughly the same. A startup adding engineers, building a sales team, or paying more to serve growing usage usually needs a month-by-month forecast.

As Sequoia puts it in its 2022 Extending Your Runway presentation: “Runway is not static.” Its framework connects the cash you have to the milestones you need to reach.

Work backward from the next fundable milestone

What will this round pay for? Be specific. For a seed-stage software company, that might mean customer cohorts that keep renewing, a repeatable sales process, and enough revenue to show the process works. For a hardware company, it might be a working product, manufacturing readiness, and paid deployments.

Agree on the evidence with your board and investors. A revenue target by itself doesn't establish that your company can raise.

In Y Combinator's seed fundraising guide, Geoff Ralston writes that “the amount you are asking for must be tied to a believable plan.” The useful principle is to connect the capital to the progress it buys. The guide's 2016 time and round-size examples aren't current market benchmarks.

Some of that work can overlap. Start investor relationships before you're actively raising. But don't assume investors will commit before the evidence exists, or that a term sheet means the cash has arrived. Techstars' fundraising toolkit warns founders to expect the process to “take longer than expected.”

Build a monthly forecast around how you spend and grow

Use a rolling forecast that reaches past your next fundable milestone and the raise after it, typically 18 months or more. If the milestone sits farther out, extend the horizon. Detailed near-term assumptions matter more than precise-looking numbers three years away.

1. Start with cash you can use

Reconcile your bank balances and accessible cash equivalents. Exclude restricted funds. Keep undrawn credit and a hoped-for round out of opening cash.

Put outstanding bills, signed contracts, and other obligations into the months you'll pay them. Don't subtract the same obligation from opening cash and then include it again in forecast spending. That counts it twice.

2. Build the hiring plan by start month

Include salary, employer payroll costs, benefits, recruiting, equipment, and any ramp time before a hire contributes to revenue. Separate hires you've committed to from hires that depend on hitting a target.

a16z's cash-management guidance for founders makes the connection directly: “knowing your headcount plan is essential to understanding your cash needs.”

3. Separate revenue from cash collection

Forecast new customers or new recurring revenue, churn, pricing, and when customers pay. An annual contract signed in March might pay in May. A paid pilot might never expand. Annual prepayments help cash today but also create a service obligation for the coming year.

Put cloud costs, support, implementation, and other costs of serving customers alongside the growth assumptions. More revenue doesn't automatically mean less burn.

4. Include the spending outside your monthly run rate

Model equipment, annual software renewals, security work, recruiting fees, and debt payments when they'll clear. A hiring plan can look affordable on salary alone and still leave out a substantial amount of cash spending.

Ending cash = opening cash + cash collected − cash paid out

Roll each month's ending balance into the next month's opening balance. Keep future financing on a separate line, and make the no-new-funding version your starting view.

How 20 months becomes 14

Consider an illustrative seed-stage B2B software company with $3 million in available cash. Last month, it collected $50,000 and spent $200,000. That gives it the headline 20 months of runway.

The operating plan adds three people in month four and another three in month seven. Sales, customer delivery, and operating costs rise too. Collections grow, but spending grows faster.

Illustrative assumptions, not a startup benchmark. Cash spent includes payroll and other operating payments. There are no new financing receipts, debt payments, capex, or income-tax payments in this example. A negative balance shows a funding gap.

The company isn't profitable. It doesn't need to be for this example to make sense. It does need to know what the additional spending will prove before the money runs out.

Your fundraising deadline arrives earlier

Suppose this team expects to have repeatable sales and retention evidence by month ten. It assumes six months for the next fundraise and adds three months for delays. Those are planning assumptions, not a promise about how long any raise will take.

Working backward from the reserve breach in month twelve gives an approximate fundraising start deadline around month three:

Monthly buckets make this approximate. Check actual payment dates before setting a deadline. Also avoid counting the same cushion twice: the cash reserve is a balance you intend to protect; the extra three months covers uncertainty in the fundraising schedule.

In its 2022 framework, Sequoia recommended reaching the funding milestone with another 12 months of runway. That was guidance for a difficult market, not a universal rule. Its lesson still applies: arriving at the milestone with almost no cash leaves you exposed.

This team can reduce or delay spending, bring forward credible evidence, or pursue financing earlier with a different amount or set of terms. A smaller team may extend runway but also delay the product. Reforecast both sides of that tradeoff.

Test three versions before you approve the next hire

a16z's 2022 down-market framework recommends scenario planning and adjusting spending as results develop. For this forecast, use three practical versions:

For Gulf South founders, Boot64 Ventures offers a useful local perspective: “Design for downside.” Its post suggests 18–24 months of runway alongside slower hiring and stronger commercial evidence. Treat that as guidance to test against your own plan, rather than a number to copy into a deck.

Set triggers while you still have options. For example: if new recurring revenue misses plan for two consecutive months, pause uncommitted hires and rerun the forecast. If the next milestone moves out, update the fundraising timetable that week. Don't let an unchanged fundraising date hide a changed business.

Refresh it monthly, and use it in real decisions

After each close, replace forecasts with actual results, reconcile cash, and explain the differences. Separate a delayed customer payment from a lost customer. Separate a delayed hire from a permanent saving.

Bring four things to the board: cash today, the reserve-breach month without new funding, the next milestone and its expected date, and the action required if the downside case develops.

When runway falls into the nine-to-six-month range, start the raise and build a Default Alive plan at the same time: what you would cut, in what order, and whether the company reaches profitability on the cash it has if the round slips. Keep it beside the longer forecast so you can still see whether the company can reach its next milestone.

Build your startup runway forecast

The runway calculator gives you a quick starting estimate. Use the longer forecast to connect that estimate to the business you're actually building.

Need help connecting your hiring plan, growth assumptions, and next raise? Work with Countabl to build a forecast you can use before you commit the cash.