Figurely

Cash Flow Runway Calculator

The total cash you can actually spend today: bank balance plus anything liquid you'd genuinely use to keep going.

Everything that leaves the account in a typical month: salaries, rent, software, contractors, your own drawings.

Cash you reliably collect each month. Use money actually received, not invoiced — late payers don't extend runway.

Try a scenario:
— Runway (months)
Monthly net burn — Expenses minus revenue — the cash you lose each month after what you bring in.
Runway (weeks) — The same runway expressed in weeks (≈4.345 weeks per month) for shorter, sharper planning.

Enable JavaScript to calculate instantly. The full method is explained below, so the page is useful either way.

Runway is the number that quietly kills businesses. Not a bad product, not weak demand — running out of cash before any of that gets fixed. A company can be growing, profitable on paper, and full of promising pipeline, yet still fail simply because the bank balance hit zero on a Tuesday and payroll was due on the Friday. Runway is how many months stand between you and that Tuesday, and it is the single figure every founder should be able to recite from memory.

This calculator works it out the way investors and CFOs do: net monthly burn against cash in the bank. You enter the cash you can actually spend, what leaves the account in a typical month, and the revenue you genuinely collect. It returns your monthly net burn, your runway in months, and the same figure in weeks for tighter situations. It is built for UK small businesses and freelancers, the logic is explained in full below, and it is honest about what it can't see — when revenue covers costs it tells you cash isn't the constraint rather than printing a meaningless number.

How this calculator works

Two short formulas do all the work:

Monthly net burn = monthly expenses − monthly revenue. This is the real rate cash leaves the business once the money coming in is netted off. Revenue doesn't have to cover costs for the figure to be useful — it just reduces how fast the balance falls.

Runway (months) = cash on hand ÷ monthly net burn. Each month consumes one net-burn's worth of cash; divide and you get how many months the balance survives. Runway (weeks) is that same figure × 4.345 (the average number of weeks in a month), useful when you're counting down rather than planning quarters. If revenue meets or beats expenses, net burn is zero or negative — there is no cash-limited runway at all — and the calculator says so plainly instead of dividing by zero or returning a misleading number.

Worked example

Suppose you have £30,000 in the bank, monthly expenses of £12,000, and monthly revenue of £4,000. Monthly net burn = £12,000 − £4,000 = £8,000. Runway = £30,000 ÷ £8,000 = 3.75 months, which is 3.75 × 4.345 ≈ 16.3 weeks. So at this rate the account empties in just under four months. That's the planning horizon: every decision about hiring, spending, or fundraising has to fit inside roughly sixteen weeks, and lifting revenue or trimming expenses both directly extend it.

Assumptions & limits

  • Burn is assumed steady. A one-off bill, tax payment, or seasonal dip will shorten real runway — re-run it whenever your monthly pattern changes.
  • No funding events are modelled: a loan, grant, or investment isn't counted until the cash is actually in your balance.
  • Figures are treated as cash, ex-VAT and net of what you collect. Invoiced-but-unpaid revenue doesn't extend runway; only money received does.

Frequently asked questions

What's a healthy runway?
A common rule of thumb is to keep at least 6 months, and 12–18 months is comfortable for a funded business. Under 3 months is a red flag that should be driving urgent decisions. The right floor depends on how predictable your revenue and costs are — volatile businesses need more.
What's the difference between burn rate and net burn?
Gross burn is everything you spend in a month. Net burn subtracts the revenue you collect, so it reflects the actual rate your cash falls. This calculator uses net burn because that's what determines how long your balance really lasts.
Why does it say there's no runway when I'm profitable?
If revenue meets or exceeds expenses your net burn is zero or negative, so cash isn't being depleted and runway isn't limited by it. Returning a months figure there would be meaningless, so the calculator flags it instead.
Should I include my own salary or drawings in expenses?
Yes — if you need to take money out to keep going, it's a real outflow and ignoring it overstates runway. Many owners run it twice, with and without drawings, to see both the true floor and the bare-survival floor.