Runway is the single number investors ask about first, and the one that should drive most of your decisions. The Burn Rate & Runway calculator works it out from three inputs and then lets you test changes before you commit to them.
The three numbers you need
- Current cash balance — what's actually in the bank today, not including money you've been promised.
- Monthly revenue — cash coming in during a typical month. Enter
0if you're pre-revenue; that's a real answer, not a blank. - Monthly expenses — everything going out: payroll, contractors, software, rent, ads.
You can type shorthand in any money field: 50k becomes 50,000 and 1.2m becomes 1,200,000.
What it calculates
Gross burn is total cash going out each month. Net burn is expenses minus revenue — what the bank balance actually loses. Investors ask for both: a company spending $200k a month covered by $180k of revenue burns $20k, but it is still a $200k-a-month operation, and that matters when revenue is volatile. If revenue exceeds expenses you're profitable and runway is effectively infinite.
Runway is your cash balance divided by net burn: how many months until the account hits zero at today's rate.
Zero cash date is that same figure on a calendar, which tends to feel a lot more urgent than "7.4 months".
How to read your runway
- Under 6 months — most investors expect a raise to already be underway. Fundraising typically takes three to six months, so this is the point where runway becomes the constraint on everything else.
- 6 to 12 months — a good window to open conversations. You have enough time to walk away from a bad term sheet.
- Over 12 months — comfortable. Focus on growth; you're raising from strength rather than necessity.
Default alive or default dead
This is the most useful question in startup finance, and it is not the same as "how much runway do I have". Enter your monthly revenue growth and the tool simulates forward: does revenue grow to cover expenses before the cash runs out?
- Default alive — you break even with money still in the bank. You'll see which month, and how much cash is left when you get there.
- Default dead — the money runs out first. You'll also see roughly what monthly growth rate would have got you there, which turns a verdict into a target.
- Profitable — revenue already covers expenses.
Expenses are held flat in this simulation. That's deliberate and slightly optimistic in the other direction: most companies add cost as they grow, so if you're default dead with flat expenses, you're default dead.
A founder can be default dead while every individual number on the page looks reasonable. That's exactly why it's worth stating plainly.
When to start raising
If your cash runs out, the tool shows a start raising by date — six months before zero cash, because a round typically takes three to six months to close. It's the difference between raising from a position of strength and raising because you have to.
Hitting a runway target
Set a runway target (18 months is a common goal after a raise) and the tool tells you what closes the gap: cut $X of monthly expenses, or add $Y of monthly revenue. Both numbers close the same gap — founders just act on the two levers differently.
Scenario modeling
The second card models changes without touching your real numbers:
- New monthly hires and average monthly cost per hire — the fastest way to see what a hiring plan costs you in months of life. Use fully-loaded cost (salary plus taxes, benefits, and tooling), not just salary.
- Additional monthly revenue — a new contract or price change.
- Additional monthly expenses — a new tool, office, or ad budget.
The Runway Analysis panel shows your current position and the modeled one side by side, so you can see exactly how many months a decision costs.
Save scenario keeps a named plan — "hire two engineers", "cut ads 30%" — and the Saved Scenarios table compares them all against your current position, showing runway gained or lost for each. Click a name to load it back into the model. Previously you could only hold one scenario at a time, which made "two hires or four?" impossible to see side by side.
Saving and exporting
Everything saves automatically as you type — the header shows when. Use Export CSV to pull both scenarios into a spreadsheet — including gross and net burn, the start-raising date, your default alive/dead verdict, and every saved scenario — to share with a co-founder, board member, or accountant.
Trying it out first
If you're not ready to enter real numbers, click Show me an example to load a sample company. It's clearly labelled while it's loaded, and one click clears it.