Cash Runway Calculator

Divide the cash balance by net monthly burn to find the month funding runs out.

About Cash Runway Calculator

Flat-burn runway is a simple division, but burn almost always rises as headcount grows. Treating burn as a geometric series and solving for the number of months gives a materially shorter and more honest answer. Plans that assume flat burn overstate runway by months, and the shortfall lands exactly when a raise is hardest to complete.

Formula

Cash Runway

With burn growing g% a month, runway solves cash = burn × ((1+g)^n − 1) ÷ g for n

g: Monthly growth in burn
n: Runway in months

Worked example

With the default values below, Cash Runway Calculator returns Runway of 12.6. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cash availableminimum 0: 1,200,000
Net monthly burnminimum 0: 80,000
Monthly growth in burnaccepts 0–100 %: 3 %

Results

Runway: 12.6 months
Runway if Burn Stays Flat: 15.0 months
Months Lost to Rising Burn: 2.4 months
Start Raising Within: 3.6 months
Verdict: Plan a raise now

Step by step

1Values used
2Cash Runway
3Runway= 12.6 months
4Runway if Burn Stays Flat= 15.0 months
5Months Lost to Rising Burn= 2.4 months
6Start Raising Within= 3.6 months
7Verdict= Plan a raise now

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Cash Runway calculated?

With burn growing g% a month, runway solves cash = burn × ((1+g)^n − 1) ÷ g for n Flat-burn runway is a simple division, but burn almost always rises as headcount grows. Treating burn as a geometric series and solving for the number of months gives a materially shorter and more honest answer.

Why does Cash Runway matter?

Plans that assume flat burn overstate runway by months, and the shortfall lands exactly when a raise is hardest to complete.

What values do I need to enter?

This calculator takes 3 inputs: Cash available, Net monthly burn, Monthly growth in burn. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.