Free Cash Runway Calculator

Estimate how many months your business can operate before running out of cash, from balance, expenses, and income.

The cash runway calculator answers the single most important question for an early-stage business: how long can we keep operating with the cash we have? Enter your current cash balance, average monthly expenses, and average monthly income, and the calculator returns the monthly net burn (expenses minus income) and the runway in months — cash balance divided by net burn. The convention is explicit: burn is positive when expenses exceed income, and if income covers expenses the calculator refuses to produce a runway because the business is not burning cash. This is deliberately a simple, transparent model: it assumes expenses and income stay flat, ignores seasonality and one-off items, and treats the runway as a planning estimate rather than a forecast. Money arithmetic is decimal-exact and rounding applies only to display. Everything runs locally in your browser — your financial figures never leave your device and are never logged. Use this calculator monthly as a health check, before a fundraising conversation, or when deciding how long current reserves can fund product development.

Processed locally in your browser

How is the result calculated?

Startup check: 60,000 balance, 25,000 expenses, 5,000 income

A startup has $60,000 in the bank. Monthly expenses run $25,000 and monthly income is $5,000, so the net burn is $20,000/month. Runway is 60,000 / 20,000 = 3 months. With a typical 3–6 month fundraising process, this is a signal to reduce burn or accelerate revenue immediately — runway alone does not tell you how fast you can fix it.

Example input and output
Input	Value
cashBalance	`60000.00`
monthlyExpenses	`25000.00`
monthlyIncome	`5000.00`
Result	Net burn $20,000.00/month · runway 3.0 months

What is the formula and its assumptions?

Monthly net burn

net burn = monthly expenses − monthly income

Formula terms
Symbol	Meaning
`monthly expenses`	average total cash spent per month
`monthly income`	average cash received per month

Runway in months

runway = cash balance / net burn

Formula terms
Symbol	Meaning
`cash balance`	cash and equivalents on hand today
`net burn`	expenses minus income per month

A runway of 6.0 means the cash runs out in six months at the current burn. Include committed but not yet paid obligations in expenses for a more honest number.

What are the most common mistakes?

Using gross burn instead of net burn, which understates runway when income exists.
Including non-cash expenses like depreciation, which inflates burn and shortens the runway falsely.
Forgetting upcoming committed payments (annual licenses, payroll spikes) that are not yet in the monthly average.

What are the assumptions and limitations?

Assumes flat expenses and income — seasonality, hires, and product launches change the picture.
Runway is a planning estimate from averages, not a financial forecast or investment advice.
Cash balance should be cash and equivalents, not revenue that has not been collected yet.

Where do the numbers come from?

CFI — Burn Rate

Last reviewed August 4, 2026 · Version 1.0.0 · Toolivaro does not guarantee external content.

Frequently asked questions

What is burn rate?

Burn rate is how fast a business spends cash. Gross burn is total monthly expenses; net burn subtracts monthly income. Runway is calculated from net burn because income genuinely extends how long the cash lasts.

Why does the calculator refuse when income covers expenses?

If income exceeds expenses, the business is not burning cash — it is accumulating it, and a runway figure would be misleading. The calculator explains this instead of returning an infinite or negative number.

Should I include non-cash items in expenses?

No. Runway is about cash, so use cash expenses only: exclude depreciation and other non-cash accounting items, but include everything that actually leaves the account, including committed one-off payments due within the runway period.

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Reviewed by the Toolivaro editorial team per our methodology Methodology · Editorial policy