Startup Runway Calculator: Months of Cash at Current Burn
Work out a startup's runway — the number of months its current cash will last at the current rate of net burn.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Months of runway |
|---|---|
| $500k cash · $50k burn | 10 |
| $2M cash · $150k burn | 13.33 |
| $120k cash · $20k burn | 6 |
| $8M cash · $400k burn | 20 |
How This Calculator Works
Enter the cash on hand and the net monthly burn — cash out minus cash in. The calculator divides one by the other to give the months of runway. The figure assumes today's burn rate holds; revenue growth extends it, faster hiring shortens it.
The Formula
Recovery Period
Fixed Cost is the upfront amount, Benefit per Period is the recurring gain that pays it back
Worked Example
A startup with $500,000 in the bank burning $50,000 a month has 10 months of runway. Under 12 months is usually the trigger for opening the next round — fundraising itself takes months, and closing on empty rarely ends well.
Key Insight
Runway is the most important number on a startup's dashboard, because it sets the deadline for every other decision. Most founders watch a six-month minimum: any closer and the choice between cutting costs and raising is no longer theirs to make.
Frequently Asked Questions
What is runway?
It is the number of months a startup can keep operating at its current burn rate before cash runs out. Cash on hand divided by net monthly burn.
Gross or net burn?
Use net — cash out minus cash in. Gross burn ignores revenue and overstates how quickly the bank account drains, which paints an unfair picture of a revenue-generating company.
When should I start fundraising?
Most founders kick off a round with 9 to 12 months of runway left. Fundraising itself takes months, and conditions almost always tighten as the deadline approaches.
What if burn is uneven?
Use the recent three- to six-month average. A single noisy month — a one-off bonus, a large refund — distorts the figure and is not what 'current burn' usually means.
Does this assume revenue stays flat?
Yes. The runway shown is at today's net burn. Revenue growth lengthens it, faster hiring shortens it — rerun the figure whenever burn changes meaningfully.
Related Calculators
Methodology & Review
Runway is cash on hand divided by net monthly burn. Net burn is monthly cash out minus monthly cash in. The figure assumes the current burn holds; growth in either direction shortens or extends it.
Written by Ugo Candido · Last updated May 17, 2026.