Startup Runway Calculator

See how many months of cash you have left and the month it runs out, from a simple burn rate or from revenue and expenses that grow over time.

Results

Runway

14.5 months

At this pace cash runs out around January 2028.

Zero-cash date: January 2028
Monthly burn now: $120,000; Net burn in month 1
Monthly burn in a year: $152,189; Net burn in month 13
Cash in 12 months: $390,549
Break-even: Not modeled
Average burn until zero: $137,694

Cash balance by month

Cash out

TodayApr ’27Jan ’28

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The math

How runway is calculated

Runway is how long your cash lasts if nothing changes. The simplest version is cash divided by monthly net burn. This calculator goes one step further and lets burn, revenue and expenses grow each month, because they almost always do.

Project each month. Start from today’s balance and subtract that month’s net burn. With revenue and expenses, net burn is expenses minus revenue, each growing at its own rate.
Find the zero point. The month the balance crosses zero is your runway. The last month is counted partially, assuming spending is spread evenly through it.
Convert to a date. Adding the runway to today gives the zero-cash month shown on the chart.

If revenue grows faster than expenses, net burn shrinks and may turn positive before cash runs out. The calculator reports that as default alive and shows the break-even month.

Net burn in month m = burn x (1 + growth)^(m - 1)
  or = expenses x (1 + gE)^(m - 1)
       - revenue x (1 + gR)^(m - 1)
Cash after month m  = cash after month m-1 - net burn in month m
Runway              = months until cash reaches zero

Assumptions and simplifications

Growth rates compound monthly and stay constant. Real burn tends to step up with hires rather than rise smoothly.
Month 1 is the month starting today. Dates are approximate to the month.
No new funding, debt, interest income, taxes or timing gaps between billing and collection.
The projection runs up to 10 years.

Worked example

$2M cash, $120K burn growing 2% a month

Burn in month 1: $120,000
Burn in month 12: $149,205
Cash after 12 months: $390,549
Cash after 14 months: $83,127
Month 15 burn: $158,337
Flat-burn runway (no growth): 16.7 months

Runway14.5 months

Frequently Asked Questions

Common questions about the Runway calculator and the math behind it.

What is the difference between gross burn and net burn?

Gross burn is everything you spend in a month. Net burn is spending minus the cash that comes in, mostly revenue. Runway uses net burn, because that is how fast the bank balance actually falls. Switch the calculator to "Revenue and expenses" to model the two separately.

How many months of runway should a startup have?

There is no single right number; it depends on how long your next milestone and fundraise will take. Fundraising itself often takes several months, so many founders start well before the last six months of cash. Use the zero-cash date here to work backward from the milestones you need to hit first.

What does default alive mean?

A company is default alive if, at its current revenue growth and expenses, it reaches profitability before the money runs out, without raising again. In this calculator that is the case when cash never hits zero within the 10-year projection, usually because revenue growth catches up with expenses.

Why does burn growth change runway so much?

Growth compounds. A burn that rises 2% a month is about 27% higher a year later, so each month costs more than the last and the final months go fast. Try setting burn growth to zero to see the flat-burn runway, which is simply cash divided by burn.

Does this include fundraising, debt or one-off costs?

No. It projects the cash you have today with smooth monthly growth. Add expected one-off payments to monthly expenses as an average, or reduce starting cash by them. Model a planned raise by adding it to cash and rerunning.

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