Tools
Cash runway calculator: months of cash left
How many months of cash do you have left?
Enter two numbers — your cash on hand and your average monthly net burn — and see how long your cash lasts at the current rate. It’s plain arithmetic on your own figures, not advice: nothing is sent anywhere, and a QuickBooks® ProAdvisor can help you turn it into a real forecast.
ToolsCash Runway CalculatorBy TechBrot2026-10-21
§ TL;DR
Cash runway is how long your cash lasts at your current burn: runway = cash on hand ÷ average monthly net burn. This tool does that one calculation on your own numbers. If you’re cash-flow positive, it says so — there’s no runway limit.
It’s a model of your inputs, not financial advice, and it runs entirely in your browser. A fractional CFO conversation turns a single number into a forward forecast.
§ 01 · The calculator
Calculate your cash runway.
Enter your figures; the result updates as you type. Your figures are worked out in your browser and are never sent to us. Our analytics records that the tool was used and which field you changed, never what you typed. Nothing else is sent until you decide to book a call.
Cash runway
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Enter your cash on hand and average monthly net burn above.
§ 02 · No black box
How cash runway is calculated.
Runway answers one question: at the rate you’re spending net of revenue, how long until the cash runs out? The math is runway in months = cash on hand ÷ average monthly net burn, where net burn is your monthly expenses minus your monthly revenue. If revenue exceeds expenses, net burn is zero or negative — you’re not burning cash, so there’s no runway limit, and the tool says exactly that instead of dividing by zero.
The hard part isn’t the division — it’s getting an accurate burn number. Burn should be an average over a few representative months, not your best or worst single month, and it should reflect real cash movements, not accrual timing. That’s why accurate books matter: a runway figure built on guesswork is worse than none.
This is a flat-rate snapshot — it assumes today’s burn holds steady. In reality burn changes with hiring, seasonality, and growth. Use the number as a sanity check, then build a real forward forecast. That’s a model of your inputs, not advice.
STEP 1
Your own numbers
in your browser
STEP 2
Runway figure
instant, open math
STEP 3
Free discovery call
30 min · no obligation
STEP 4
A cash-flow forecast
on your real books
§ 03 · Related
Where to go next.
§ 04 · Questions
Questions about cash runway.
Does this calculator store or send my numbers?
No. The calculation runs in your browser, using only the figures you type, and those figures are never sent to us. Like the rest of the site, the page reports to our analytics that the tool was used and which field you changed, never what you typed. Nothing is stored on our side unless you choose to book a call and tell us yourself. You do not have to give us your name or email to use it.
Why did it say ‘no runway limit’?
Because the net burn you entered was zero or negative — your revenue covers or exceeds your expenses, so you’re not drawing down cash. There’s no finite runway in that case. If your situation changes and you start burning cash, runway = cash ÷ monthly burn.
Should burn include one-time costs?
For a steady-state runway figure, use a normal recurring burn and treat big one-offs separately, or you’ll understate your true runway. The cleaner approach is a proper rolling forecast that schedules known one-time items — which is what a fractional CFO builds.
How accurate is this?
It’s exact arithmetic on your inputs, but it’s a flat snapshot — it assumes today’s burn holds. Real runway moves with hiring, seasonality, and growth. Treat it as a sanity check on your own numbers, not a forecast or advice.
How can TechBrot help beyond the number?
We keep your books accurate so burn and cash are real figures, and our cash-flow and fractional CFO engagements build forward forecasts that show runway changing over time. Start with a free discovery call to talk it through.
From a number to a forecast