Cash Runway Calculator: How Many Months You Have Left

Cash runway is the most important number on your financial dashboard. It is how many months until your bank balance hits zero at your current spending pace. Once you know that number, every business decision becomes clearer.

The calculation

Runway is one division problem:

Runway (months) = Bank Balance ÷ Net Monthly Burn

If your bank shows $400,000 and your net burn is $32,000/month: $400,000 ÷ $32,000 = 12.5 months. That is your runway.

What "net burn" actually means

Net burn is monthly expenses minus monthly revenue. Use cash actually received, not invoiced. A customer who owes you $10,000 but has not paid does not extend your runway by a single day.

Scenario	Monthly expenses	Monthly revenue	Net burn
Pre-revenue	$25,000	$0	$25,000
Some revenue	$60,000	$15,000	$45,000
Almost breakeven	$80,000	$72,000	$8,000
Profitable	$50,000	$65,000	−$15,000 (cash growing)

Runway thresholds — what each level means

Months of runway	Meaning	What to do
24+ months	Comfortable	Focus on growth, hire confidently
18-24 months	Healthy	Standard operating mode, plan next raise
12-18 months	Watch list	Tighten new spend, refine fundraising story
6-12 months	Action zone	Actively fundraising or cutting costs
3-6 months	Danger	Emergency cuts, bridge round, or wind down
Under 3 months	Critical	Daily cash management, hard decisions

Why 18 months is the magic number

VCs and seasoned operators repeat the "18 months of runway" rule for a reason. Here is the math:

• Months 1-6: Use the cash to do real work. Build, ship, learn.
• Months 7-12: Start showing results. Metrics improve, traction story builds.
• Months 13-18: Fundraise from a position of strength, not desperation.

If you only have 12 months, you compress the work phase to 3-6 months and start raising too early. If you have less than 9 months, investors smell the panic and discount your valuation.

Three ways to extend runway

1. Cut expenses. Direct, immediate, painful. Every dollar cut from monthly burn extends runway proportionally.
2. Grow revenue. Slower but compounding. Each new $1,000 of MRR shaves $1,000 off your monthly burn forever.
3. Raise more cash. The traditional answer, but it dilutes you and is not always available.

Most startups should pursue all three at once during a runway crunch. Cut expenses to buy time, accelerate sales to demonstrate momentum, then close a bridge round on those improved metrics.

The "zero date" mindset

Runway in months feels abstract. The exact date your money runs out is visceral. Our burn rate calculator shows the literal calendar date when your balance hits zero. Once you see "Aug 14, 2027" you stop thinking in vague months and start thinking in real time.

Tracking runway monthly

Runway is not a one-time calculation. Update it on the first of every month with fresh numbers:

• Pull bank balance from your business account
• Sum last month's expenses and revenue
• Recalculate runway
• Compare to last month — is it growing or shrinking?

If runway shrinks two months in a row, something is off. Either expenses crept up, revenue dipped, or both. Catch it early and you have time to react.