Startup Runway Calculator
Months of runway, the zero-cash date and the burn multiple from cash, spend, revenue and growth — with the month it turns cash-flow positive, if it does.
Startup Runway Calculator: with the default inputs, runway is 11.1.
Everything you can actually spend, less anything already committed.
Total cash out each month — payroll, rent, software, everything. Not net of revenue.
Cash collected, not bookings. A signed contract you invoice in ninety days does not pay this month's payroll.
Compounding month on month. 8% a month is roughly 2.5× a year — fast, and rarely sustained for long.
Hiring and cost inflation. Setting this to zero is the most common way runway models flatter themselves.
Months until the cash balance hits zero. Blank when the business never runs out.
- In words
- 11 months of runway from $1,200,000, burning $120,000 net this month.
- Zero-cash date
- August 10, 2027
- Default alive or default dead?
- Default dead — at this growth rate the cash runs out before revenue catches spend. Raising, cutting or growing faster are the only three options.
- Net burn this month
- $120,000
- Gross burn this month
- $180,000
- Month revenue covers spend
- 21Blank if it doesn't within 50 years at these growth rates.
- Burn multiple
- 1.17Net burn over the next 12 months ÷ net new annualized revenue added. Under 1 is exceptional, over 2 is expensive growth.
- Net burn over 12 months
- $1,275,549
- Annualized revenue added in 12 months
- $1,093,082
- Cash left in 12 months
- -$75,549
- Start raising by month
- 5Runway less six months, because a round takes about that long to close.
Assumptions
- Revenue and spend compound at constant monthly rates from today's figures; month 1 uses the values as entered.
- Revenue means cash collected, not bookings or ARR.
- Runway is the point the cash balance crosses zero, interpolated within the month.
- The burn multiple uses the next twelve months of net burn over the annualized revenue added in that time.
- No seasonality, one-off costs, collection lags or step changes in cost.
- An expected raise, if entered, is assumed to land in full in the month given.
| Month | Revenue | Spend | Net burn | Cash at month end |
|---|---|---|---|---|
| 1 | $60,000 | $180,000 | $120,000 | $1,080,000 |
| 2 | $64,800 | $183,600 | $118,800 | $961,200 |
| 3 | $69,984 | $187,272 | $117,288 | $843,912 |
| 4 | $75,583 | $191,017 | $115,435 | $728,477 |
| 5 | $81,629 | $194,838 | $113,208 | $615,269 |
| 6 | $88,160 | $198,735 | $110,575 | $504,694 |
| 7 | $95,212 | $202,709 | $107,497 | $397,197 |
| 8 | $102,829 | $206,763 | $103,934 | $293,263 |
| 9 | $111,056 | $210,899 | $99,843 | $193,420 |
| 10 | $119,940 | $215,117 | $95,176 | $98,244 |
| 11 | $129,535 | $219,419 | $89,883 | $8,360 |
| 12 | $139,898 | $223,807 | $83,909 | -$75,549 |
Net burn is spend less revenue. Once it goes negative the business is generating cash and the balance turns back up.
How this is worked out
The formula
Net burn (month t) = spend₀ × (1 + spend growth)^(t−1) − revenue₀ × (1 + revenue growth)^(t−1)
Cash (month t) = cash (t−1) − net burn (t)
Runway = the month cash first goes below zero, plus the fraction that month covers
Simple runway = cash ÷ current net burn (the no-growth version)
Burn multiple = net burn over the next 12 months ÷ net new annualized revenue added
= Σ net burn (months 1–12) ÷ (revenue in month 13 − revenue now) × 12Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Cash in the bank
- Everything you can actually spend, less anything already committed.in dollars · 0 or more · defaults to 1200000
- Monthly spend (gross burn)
- Total cash out each month — payroll, rent, software, everything. Not net of revenue.in dollars · 0 or more · defaults to 180000
- Monthly revenue
- Cash collected, not bookings. A signed contract you invoice in ninety days does not pay this month's payroll.in dollars · 0 or more · defaults to 60000
- Monthly revenue growth
- Compounding month on month. 8% a month is roughly 2.5× a year — fast, and rarely sustained for long.a percentage · from -50 to 100 · defaults to 8
- Monthly spend growth
- Hiring and cost inflation. Setting this to zero is the most common way runway models flatter themselves.a percentage · from -50 to 100 · defaults to 2
- Starting from(under More options)
- The month the cash balance is measured. The zero-cash date counts forward from here.defaults to today
- Expected raise(under More options)
- Money you're confident will land. Leave at zero for the honest version.in dollars · 0 or more · defaults to 0
- Raise lands in month(under More options)
- A number.from 1 to 120 · whole numbers only · defaults to 6
What you get back
- Runwaymain answer
- Months until the cash balance hits zero. Blank when the business never runs out.
- In words
- Zero-cash date
- Default alive or default dead?
- Net burn this month
- Gross burn this month
- Month revenue covers spend
- Blank if it doesn't within 50 years at these growth rates.
- Burn multiple
- Net burn over the next 12 months ÷ net new annualized revenue added. Under 1 is exceptional, over 2 is expensive growth.
- Net burn over 12 months
- Annualized revenue added in 12 months
- Cash left in 12 months
- Start raising by month
- Runway less six months, because a round takes about that long to close.
What this assumes
- Revenue and spend compound at constant monthly rates from today's figures; month 1 uses the values as entered.
- Revenue means cash collected, not bookings or ARR.
- Runway is the point the cash balance crosses zero, interpolated within the month.
- The burn multiple uses the next twelve months of net burn over the annualized revenue added in that time.
- No seasonality, one-off costs, collection lags or step changes in cost.
- An expected raise, if entered, is assumed to land in full in the month given.
About this calculator
Runway is the number of months before the bank account reaches zero, and it is the only operating metric that is also a deadline. Everything else at a startup can be argued about; the date the payroll fails cannot.
Gross burn, net burn, and why the difference matters
Gross burn is everything going out — payroll, rent, cloud bills, the lot. Net burn is gross burn less the cash you actually collect. Runway is driven by net burn, but gross burn is the number you can cut this week, and in a crisis it's the one that matters, because the revenue line may not be as reliable as the spreadsheet claims.
Note the word collect. Bookings are not cash. A signed annual contract you invoice in ninety days does not pay this month's payroll, and a runway model built on ARR rather than collections is a model of a company that doesn't exist yet.
Why the simple formula is wrong
Cash ÷ net burn is the version everyone quotes, and it's wrong in two directions at once: revenue is growing, which extends the runway, and spend is growing too, which shortens it. This calculator compounds both. On the defaults — $1.2m of cash, $180k of spend, $60k of revenue, revenue growing 8% a month and spend 2% — the naive answer is 10.0 months and the honest answer is 11.1 months, because revenue outruns costs. Flip spend growth to 8% and the same company has 9 months.
Set spend growth to zero if you like, but almost every plan hires, and payroll is the line that grows.
Default alive or default dead
Paul Graham's question: on your current trajectory, with no new money, do you reach profitability before you reach zero? A default alive company can choose whether to raise. A default dead one has to, and everyone in the room knows it — including the investor. The status line answers that question directly, and it's worth re-answering every month, because the trajectory changes faster than the plan does.
The burn multiple
Coined by Craft Ventures' David Sacks: net burn ÷ net new annualized revenue. It answers "how many dollars did we burn to add a dollar of recurring revenue?" — a capital-efficiency measure that is much harder to game than growth rate alone. Rough scale: under 1× is exceptional, 1–1.5× is good, 1.5–2× is acceptable, above 2× means growth is being bought rather than earned, and above 3× the model needs fixing before the next round, not after it.
Reading the results
The zero-cash date is the one to put in the board deck. Start raising by subtracts six months from the runway, because a round takes three to six months from first meeting to cleared funds and you never want to be negotiating from a position of two months' cash. If you enter an expected raise under More options, treat the answer with suspicion: money you have not raised is not runway, and the calculator will say so.
What this doesn't model
Seasonality, one-off costs, collections timing, a hiring plan with actual start dates, or the way costs step rather than glide when you sign an office lease. It also assumes constant growth rates, which no company has. Use it to find the shape and the deadline; use a monthly cash forecast for the detail.
Frequently asked questions
▸How do you calculate startup runway?
Cash divided by net monthly burn gives the naive answer. The honest one compounds revenue growth and cost growth month by month and finds when the balance crosses zero — which can differ from the simple figure by several months in either direction.
▸What's the difference between gross burn and net burn?
Gross burn is total cash out; net burn is gross burn less cash collected. Runway depends on net burn, but gross burn is what you can actually cut, and it's the number to watch when revenue is uncertain.
▸What is a good burn multiple?
Under 1× is exceptional, 1–1.5× good, 1.5–2× acceptable, above 2× expensive. It measures dollars burned per dollar of new annualized revenue, so it exposes growth bought with money rather than earned with product.
▸How much runway should a startup have before raising?
Twelve to eighteen months after the round closes, and you should start the process with at least six to nine months left. Rounds take three to six months, and negotiating with two months of cash is negotiating from the worst possible position.
▸What does default alive mean?
Paul Graham's term for a company that reaches profitability on its current trajectory before it runs out of money — with no new funding. A default alive company chooses whether to raise; a default dead one has to, and investors can tell the difference.
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