Cash Runway Calculator
Total cash in bank accounts
Average cash received per month
Rent, salaries, subscriptions, insurance
COGS, contractor fees, commissions (0 if none)
Upcoming one-time expense (optional)
Find out how many months your business can survive at its current burn rate. Enter your current cash balance, monthly revenue, and monthly costs - the calculator shows your runway in months, the date your cash runs out, how much revenue you need to break even, and a month-by-month cash projection you can download. You can model a growing or shrinking revenue trend to see how improving or worsening performance changes your runway.
How to use this tool
- 1Enter your current cash balance - the total amount of cash in your bank accounts and liquid reserves, not assets or receivables.
- 2Enter your monthly revenue - the average cash you actually receive each month, not invoiced or deferred amounts. If revenue varies, use a realistic average.
- 3Choose a revenue trend. If revenue is stable, leave it as is. If growing or shrinking, select the trend and enter the monthly percentage rate (for example, 5 means 5% growth per month).
- 4Enter monthly costs: fixed costs are constant expenses such as rent, salaries, subscriptions, and insurance; variable costs fluctuate with activity such as cost of goods sold, contractor fees, and commissions. Enter 0 for variable costs if you have none.
- 5Optionally add a known one-time upcoming expense (such as a tax payment or equipment purchase) and the month number it falls in. The projection accounts for this spike.
- 6Read your runway in months and the colour-coded indicator. Download the month-by-month CSV to share with investors or your accountant.
Formula used
Example
Cash balance: $120,000. Monthly revenue: $8,000. Revenue trend: growing 10% per month. Fixed costs: $18,000 (3 salaries, office, tools). Variable costs: $2,000. Net burn in month 1: $12,000. The simulation shows revenue overtakes costs in month 9 (when MRR reaches $20,000), and the business survives to profitability with $42,000 remaining - a healthy outcome even though initial runway without growth would have been only 10 months.
Cash balance: $85,000. Monthly revenue: $22,000. Revenue trend: shrinking 8% per month (losing a major client). Fixed costs: $24,000. Variable costs: $4,000. Net burn in month 1: $6,000, rising as revenue falls. The simulation shows cash runs out in month 11. Break-even revenue is $28,000 - $6,000 above current revenue. The owner needs to either cut costs or replace the lost revenue within 6 months to maintain a safe buffer.
Common use cases
- Startup founders checking how long they can operate before needing to raise another funding round
- Small business owners assessing whether current cash reserves are sufficient to cover a slow season
- Freelancers and consultants estimating how long their savings buffer lasts between contracts
- Early-stage companies modelling the impact of hiring a new employee on their remaining runway
- Business owners preparing a cash flow summary for a bank loan or investor meeting
- Finance teams running scenario analysis on what happens if a major client cancels or revenue dips
Common mistakes
- Using invoiced revenue instead of cash received - if payment terms are 30-60 days, your actual cash inflow is lower than your invoiced revenue and your real runway is shorter
- Forgetting employer taxes, pension contributions, and benefits when entering salary costs - the true cost of each employee is typically 20-35% more than their gross salary
- Entering gross revenue without deducting cost of goods sold - if you are a product business, revenue is not profit; use net revenue or enter COGS as a variable cost
- Using a stable trend when revenue is clearly seasonal - if your business has strong and weak months, the stable average underestimates risk during slow periods
- Ignoring one-time upcoming expenses such as tax bills, lease renewals, or equipment replacements that will cause a cash spike
Frequently asked questions
What is cash runway?
Cash runway is the number of months a business can continue operating at its current burn rate before it runs out of cash. It is calculated by dividing the current cash balance by the net monthly burn rate (costs minus revenue). A runway of 12 months or more is generally considered comfortable; under 6 months is a warning sign that requires immediate action.
What is burn rate?
Burn rate is the net amount of cash a business spends each month above what it earns. Gross burn is total monthly spending. Net burn is gross burn minus revenue. For example, if you spend $20,000 per month and earn $8,000, your net burn is $12,000. That is the number that determines how quickly you are consuming your cash reserves.
What counts as cash balance?
Cash balance should include only liquid assets you can use immediately: current bank account balances and short-term savings. Do not include accounts receivable (money owed to you but not yet paid), equipment value, inventory value, or credit lines you have not drawn on. Be conservative - actual runway is only as reliable as the cash balance you enter.
My revenue is growing. Will the calculator account for that?
Yes. Select Growing under Revenue trend and enter your estimated monthly growth rate as a percentage. The calculator runs a month-by-month simulation where revenue compounds at that rate each month. If revenue grows fast enough to cover costs before cash runs out, the result will show the month you reach cash-flow break-even instead of a runout date.
How accurate is this estimate?
The estimate is as accurate as the inputs you provide. In practice, revenue and costs fluctuate month to month, customers pay late, unexpected expenses arise, and market conditions change. Treat this as a planning scenario rather than a precise forecast. Run multiple scenarios - optimistic, realistic, and pessimistic - to understand the range of outcomes.
What is break-even revenue?
Break-even revenue is the monthly revenue you need to earn to cover all costs exactly, with no net burn and no growth in cash. It equals total monthly fixed costs plus total monthly variable costs. If your current revenue is below this number, your cash balance is declining every month.
Should I include credit lines or loans in the cash balance?
Only include committed, available credit you plan to draw down and have access to immediately. Do not include credit lines you have not yet applied for or that depend on future approval. If you plan to raise investment or take a loan within the runway period, model that as a future cash inflow, not as current balance - otherwise you are overestimating your actual safety margin.
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