How to use it
- 1Type the cash you have in the bank today — not committed funding that hasn't arrived.
- 2Add total monthly expenses, including salaries and taxes. Spread annual bills across twelve months.
- 3Enter monthly revenue you actually collect, then a realistic month-over-month growth rate for revenue and for expenses.
- 4Read the runway and cash-out date. Switch to Table for month-by-month figures, or Copy link to share the scenario.
Examples
Pre-revenue team after a seed round
$1.2M in the bank, $70k/month expenses, no revenue, expenses growing 3% a month as the team hires. Simple runway says 17 months; with hiring baked in, the cash runs out after about 14 months. The difference is the hiring plan — that's the number to show the board.
Bootstrapped SaaS close to break-even
$90k cash, $22k expenses, $15k MRR growing 6% a month, costs flat. Net burn today is $7k, which looks like 13 months of runway, but revenue passes costs in month 8 and cash bottoms out around $62k. You never actually run out — the question becomes whether 6% growth is believable.
Checking whether a cost cut is enough
$300k cash, $50k expenses, $10k revenue growing 10%, expenses +2%. Runway is about 7.6 months. Cutting expenses to $40k buys about three more months (10.9) and pulls break-even from month 23 to month 20 — but cash still runs out first. The cut alone isn't enough; it has to be paired with a raise. Copy each scenario's link into your planning doc.
How runway is calculated
Net burn = monthly expenses − monthly revenue. Simple runway = cash ÷ net burn. If net burn is zero or negative you aren't spending down cash, so simple runway is unlimited.
The projected runway steps forward one month at a time for up to 60 months. Month 1 uses today's figures; from month 2, revenue is multiplied by 1 + revenue growth and expenses by 1 + expense growth. Each month's net result is added to the balance. When the balance crosses zero, we interpolate inside that month, so 7.6 months means cash runs out about 60% of the way through month 8.
Break-even is the first month where revenue is at least equal to expenses. The start raising date is six months before cash-out, a common rule of thumb for how long a round takes to close.
Limitations
- infoGrowth is compounded at a constant rate. Real revenue is lumpier — model a pessimistic and an optimistic case rather than trusting one line.
- infoIt assumes you collect revenue in the month it's earned. Annual prepayments, net-60 invoices and VAT or sales tax timing all shift cash between months.
- infoNo financing is modelled: loans, revenue-based financing or a new round would extend runway and aren't included.
- infoDates are counted from today using average month length (30.4 days), so the cash-out date is accurate to within a few days.
Questions people ask
What is a good runway for a startup?
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Aim for 18 to 24 months after a raise. Fundraising typically takes around six months from first meeting to money in the bank, so anything under 12 months means you're already close to needing to start. Under six months is an emergency: cut burn or raise immediately.
What's the difference between gross burn and net burn?
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Gross burn is everything you spend in a month. Net burn is gross burn minus revenue — the amount your bank balance actually drops. Runway is calculated on net burn, which is why growing revenue extends runway even when costs stay flat.
Should I include one-off costs like annual software contracts?
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Spread them. Divide an annual payment by twelve and add it to monthly expenses; otherwise the month you pay it looks like a crisis and the other eleven look better than they are. Do the same for annual plans your customers prepay.
Why does the calculator show two runway numbers?
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The small number under the headline is simple runway: cash divided by today's net burn, assuming nothing changes. The headline number applies your growth rates month by month, so revenue growth lengthens it and expense growth shortens it. Investors usually ask for the simple one; plan with the projected one.
How do I share the result with my co-founder or investors?
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Every input is saved in the page address as you type. Use Copy link and send it — the other person opens the same numbers. Nothing is stored on our side; the link itself carries the figures.