Runway Calculator

How to use this calculator

1. Enter the Cash in the bank and your Monthly expenses.
2. Enter your current Monthly revenue and the Revenue growth per month you expect.
3. Read the Runway, or the time to break-even if revenue catches up with costs first.
4. Compare it with Runway at today's burn, and review the monthly cash table.

How runway is calculated

Net burn is monthly expenses minus monthly revenue. The simplest runway divides cash by net burn. The calculator also runs a month-by-month projection in which revenue grows at the rate you enter while expenses stay flat, and stops when cash hits zero or revenue reaches expenses.

Runway = Cash ÷ (Expenses − Revenue)

• Cash = money available now
• Expenses = total monthly costs
• Revenue = monthly income, growing by the monthly growth rate
• Net burn = Expenses − Revenue

Because growth shrinks the burn each month, the projected runway is longer than the flat one when growth is positive.

Example: $300,000 of cash

A business has $300,000 in the bank, $40,000 of monthly expenses and $15,000 of monthly revenue. Net burn is $25,000, so the runway at today's burn is 12 months.

With revenue growing 5% a month, cash lasts 19 months, but revenue is still only about $36,000 when it runs out, below the $40,000 cost. With 8% growth, revenue reaches break-even after 13 months with about $102,429 left. With no growth, the answer is the flat 12 months.

Using runway to decide

Fundraising, a new hire or a bigger campaign all take months to pay back, so decide while you still have time. Many founders try to keep a long cushion before raising or cutting costs, because a short runway weakens your negotiating position.

Test several scenarios: lower costs, slower growth, a delayed customer. If the growth case reaches break-even only barely, treat the flat case as your real plan. Link it with unit economics in the customer lifetime value calculator and the break-even calculator.

Ways to extend runway

• Cut or delay costs that do not drive revenue.
• Collect faster: shorter payment terms, deposits and annual billing.
• Raise prices on new customers.
• Negotiate supplier terms to pay later.
• Start fundraising or arranging credit well before cash gets low.

Assumptions and limits

Expenses are held flat, so any hiring or price increases are not modeled, and growth is a single constant percentage, which real revenue rarely follows. The tool ignores seasonality, delayed payments, taxes, debt repayments and one-off purchases. Revenue counted here is cash received, not invoices issued. It is a planning aid; confirm your numbers with your accountant, especially before relying on them for borrowing or investor discussions. For personal savings rather than a business, try the how long will my money last calculator.

Frequently asked questions