Most founders find out they're out of runway one month too late. Drop in three numbers — cash in the bank, what you collect each month, and what you spend — and you'll see your net burn rate and the exact month your startup runs out of money.
Enter your cash on hand, monthly revenue, and monthly expenses to instantly see your net burn rate and how many months of runway you have left. Nothing is sent to a server — every number stays on your device.
Currency and monthly/yearly are display settings — no exchange rates are applied, so enter all figures in the same currency.
Tight runway. Consider trimming expenses or raising revenue.
That's roughly July 2027 at today's pace.
Under 12 months of runway? Track it every week instead of guessing — import your bank CSV, auto-reserve taxes, and see a 12-month projection.
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Net burn rate = monthly expenses − monthly revenue. If you spend $8,000 and collect $3,000, your net burn is $5,000/mo. Gross burn ignores revenue and counts total spend.
Runway = cash on hand ÷ net burn rate. With $50,000 in the bank and a $5,000/mo net burn, you have 10 months of runway at today's pace.
Most investors want to see 12–18 months. Under 6 months is a red flag: it's usually time to cut costs, raise prices, or start a raise.
FlowingPulse keeps your burn rate, tax buffer, and runway up to date automatically — one CSV drop and you're current.
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Gross burn is every dollar that actually leaves the bank account in a month: payroll and contractors, software, hosting, rent, ads, professional fees and tax payments. Accrual costs that have not been paid yet do not belong here — burn rate is a cash measure, not a profit measure.
Gross burn = sum of all cash outflows in the month
Net burn is what actually shrinks the balance. Use cash collected, not invoiced revenue: subtract processor fees, refunds and chargebacks, and count a payment in the month it clears. When collections exceed spend, net burn goes negative — you are cash-flow positive.
Net burn = gross burn − cash collected in the month
Runway answers a single question: at today's pace, how many months until the account hits zero? Because net burn is a per-month quantity and cash on hand is a stock, dividing one by the other cancels the currency and leaves months.
Runway (months) = cash on hand ÷ net burn
If net burn is zero or negative, runway is undefined in the mathematical sense — the balance is flat or growing, so the tool shows ∞ rather than a misleading number. If your burn is lumpy (annual insurance, quarterly tax), average the last three months before dividing, otherwise a single heavy month makes runway look far worse than it is.
Smoothed net burn = (net burn M1 + M2 + M3) ÷ 3
Two founders, one contractor, no revenue yet. They want to know whether to open a round now or after the next release.
Net burn $20,000/mo, runway 12.0 months. Fundraising takes 3–6 months, so the raise has to start by month 6 — the release has to ship before then or the round starts from a weaker position.
A solo-founder product at $14,000 MRR wants to know how much hiring headroom exists before runway drops under a year.
Net burn $3,500/mo, runway 25.7 months. Adding a $4,000/mo contractor pushes net burn to $7,500 and runway to 12 months — still inside the safe band, but only if revenue keeps growing.
Retainers arrive on different dates and one client pays quarterly, so a single month tells you nothing useful.
Smoothed net burn $6,000/mo, runway 10 months. The unsmoothed December figure showed 3 months of runway, which would have triggered a panic round of cuts for no reason.
Yes. Anything that leaves the bank account counts, including debt service, VAT or sales tax remittance, and estimated income tax payments. Excluding them is the most common reason a runway number turns out to be optimistic.
Use net burn for runway. Gross burn is useful for cost benchmarking and for a worst-case scenario in which revenue stops entirely, but the balance only falls by net burn.
Monthly, right after the month closes and the bank statement is final. Founders in a raise or a turnaround usually track it weekly against a rolling three-month average.
No. The calculation runs entirely in your browser and nothing is uploaded. Prefilled figures live only in the page URL, so you control who sees a link you share.