Cash Runway Calculator

Use this calculator to estimate how many months your business can continue operating based on current cash balance and monthly burn rate. Essential for startup planning, fundraising timing, budget management, and communicating financial position to investors and board members.

What this calculator does

The cash runway calculator helps you work out how long your current cash balance will last at your current rate of spending.

It uses:

• current cash balance
• monthly burn rate

This gives you cash runway in months - the single most important number for any business managing limited cash reserves.

How to use the cash runway calculator

1. Enter your cash balance - the total cash and cash equivalents currently available to the business, excluding restricted funds or credit facilities that are not yet drawn
2. Enter your monthly burn rate - the average amount of cash the business spends each month, net of any revenue if you want to use net burn rate
3. The calculator instantly shows your cash runway in months

Use net burn rate - monthly cash outflow minus monthly revenue - for the most accurate runway figure if your business has meaningful revenue. Use gross burn rate if you are pre-revenue.

Cash Runway Formula

Cash Runway = Cash Balance / Monthly Burn Rate

Where:

• Cash Balance = current available cash and cash equivalents
• Monthly Burn Rate = average monthly net cash consumption
• Cash Runway = number of months the cash balance will last at the current burn rate

Example calculation

If:

• Cash balance = 100,000
• Monthly burn rate = 20,000

Then:

• Cash runway = 100,000 / 20,000
• Cash runway = 5 months

At a burn rate of 20,000 per month with 100,000 in the bank, the business has approximately 5 months before cash runs out - assuming burn stays constant and no new revenue or funding comes in.

What is cash runway?

Cash runway is the number of months a business can continue operating before its cash balance reaches zero, based on its current rate of cash consumption.

It assumes burn rate remains constant - which is rarely true in practice, but gives a useful planning baseline. Rising revenue reduces effective burn and extends runway. Unexpected costs or slower-than-expected growth reduce runway.

Cash runway is most commonly used by startups and early-stage businesses managing capital between funding rounds, but it is a valuable metric for any business that needs to monitor how long its cash reserves will last.

What is a good cash runway?

Most experienced founders and investors use these benchmarks:

• 18 to 24 months - considered a healthy runway that allows time to grow, hit milestones, and raise the next round without being under pressure
• 12 to 18 months - manageable but worth monitoring closely and beginning fundraising conversations
• 6 to 12 months - a fundraising process should already be underway
• Under 6 months - critical - immediate action required on either reducing burn or securing funding

The general rule of thumb is to start a fundraising process when you have 9 to 12 months of runway remaining. Raising capital takes longer than most founders expect - typically 3 to 6 months from first conversation to funds in the bank.

Why cash runway matters for startups and growing businesses

Tracking cash runway helps you:

• understand exactly how much time you have before needing additional funding or reaching profitability
• plan fundraising timing with enough lead time to avoid a distressed raise
• make informed decisions about hiring, spend, and investment based on available runway
• communicate financial position clearly to investors and board members
• identify when burn reduction is needed to extend runway without raising more capital

How to extend cash runway

Four practical levers for extending runway without additional funding:

• Reduce burn rate - audit all spending and cut or defer non-essential costs, starting with the largest line items
• Accelerate revenue - focus commercial efforts on faster-closing deals or existing customers who can expand spend
• Improve payment terms - collect from customers faster and extend payment terms with suppliers where possible
• Defer capital expenditure - push back on non-critical equipment or infrastructure investment until runway is more comfortable

Even extending runway by 2 to 3 months can make a significant difference to fundraising outcomes and negotiating leverage.

Cash runway vs burn rate

These two metrics are directly linked and must be tracked together.

• Burn rate shows how fast cash is being consumed each month - the rate of change
• Cash runway shows how long the current cash balance will last at that rate - the time remaining

Burn rate is the input. Cash runway is the output. Use the Burn Rate Calculator to calculate your monthly burn rate before using this calculator for runway.

Cash runway vs cash flow

These measure different aspects of cash management.

• Cash runway focuses on how long current reserves will last - most relevant for businesses managing finite capital
• Cash flow measures the net movement of cash in and out during a period - most relevant for businesses monitoring ongoing liquidity

Use the Cash Flow Calculator to monitor ongoing cash movement alongside runway for a complete financial picture.

When to use this calculator

Use this calculator when you want to:

• calculate your current runway before a board meeting or investor update
• model the impact of cost reductions on how long your cash will last
• evaluate different burn scenarios to inform hiring or spend decisions
• assess funding urgency and plan the timing of a capital raise
• compare runway across different months to track whether the cash position is improving or deteriorating

Common mistakes when calculating cash runway

Common mistakes include:

• using gross burn rate when the business has significant revenue - net burn gives a more accurate runway figure
• including restricted cash, undrawn credit facilities, or expected but not yet received funding in the cash balance
• assuming burn rate is fixed when it is likely to change as the business grows or contracts
• ignoring the time it takes to raise funding - a runway of 6 months is not enough time to complete most fundraising processes

Related calculations

Once you know your cash runway, you may also want to:

• Use the Burn Rate Calculator to calculate your monthly burn rate
• Use the Cash Flow Calculator to monitor ongoing cash movement
• Use the Working Capital Calculator to assess short-term liquidity position
• Use the Revenue Forecast Calculator to model when revenue growth might reduce net burn and extend runway

Useful resources

• Stripe - payment infrastructure with real-time revenue reporting to help track net burn and runway accurately
• QuickBooks - accounting software for tracking cash balances, outflows, and burn rate over time
• Xero - cloud accounting platform with short-term cash flow forecasting to model runway scenarios
• Brex - business banking and spend management platform designed for startups managing limited runway

FAQs

What is cash runway?

Cash runway is the number of months a business can continue operating before its cash balance reaches zero, based on its current monthly burn rate.

How do you calculate cash runway?

Cash Runway = Cash Balance / Monthly Burn Rate.

What is a good cash runway for a startup?

18 to 24 months is considered a healthy runway. Most experienced investors recommend starting a fundraising process when 9 to 12 months of runway remains - raising capital typically takes 3 to 6 months from first conversations to closing.

Should I use gross or net burn rate for runway calculation?

Use net burn rate - monthly cash outflow minus monthly revenue - for the most accurate runway figure if your business has meaningful revenue. For pre-revenue businesses, gross and net burn rate are the same.

What happens when cash runway runs out?

If the cash balance reaches zero and no new funding or revenue covers ongoing costs, the business cannot meet its obligations. This is why proactive runway management - extending runway through cost reduction or accelerating fundraising - is critical before reaching that point.

Can runway increase over time?

Yes. If monthly revenue grows faster than monthly costs, net burn rate decreases and runway extends automatically. A business that reaches cash flow breakeven - where revenue covers all costs - has infinite runway in theory.

How does runway affect fundraising negotiations?

Founders with longer runway negotiate from a position of strength - they are not under pressure to accept unfavourable terms. Short runway forces founders into distressed raises where investors have more leverage. Maintaining 18 months or more of runway is the most reliable way to preserve negotiating power.

What is the difference between cash runway and payback period?

Cash runway measures how long current cash will last. Payback period measures how long it takes to recover an investment from its returns. They are different concepts used in different contexts - runway for cash management, payback period for investment evaluation.

Interpreting your result

Your cash runway result should always be interpreted in context:

• compare it against your historical baseline
• review it alongside the main commercial or operational drivers behind the metric
• compare it across products, channels, periods, or segments where relevant
• avoid interpreting the result in isolation without checking the underlying input values

A single period can be noisy, so trend direction over several periods is usually more useful than one standalone result.

Data quality checklist

Before acting on this result, verify:

• the inputs use the same time period and reporting basis
• one-off anomalies are identified separately from steady-state performance
• discounts, refunds, taxes, or fees are handled consistently where relevant
• the underlying values are complete enough to support a meaningful conclusion

Small input inconsistencies can materially change the result.

How to improve this metric

Practical ways to improve this metric depend on the underlying business model, but often include:

• identify the main driver behind the result before making changes
• test one variable at a time so the impact is easier to measure
• compare performance by segment rather than only at an overall level
• review the metric regularly so changes can be caught early

Improvement is most reliable when measurement definitions remain stable over time.

Benchmarks and target setting

A good target depends on your industry, business model, and stage of growth.

When setting targets:

• compare against your own historical trend before relying on outside benchmarks
• define both minimum acceptable and aspirational target ranges
• review targets whenever pricing, cost, demand, or channel mix changes materially
• pair benchmark review with the underlying commercial context, not just the final number

Your own historical performance is usually the most practical benchmark.

Reporting cadence and decision workflow

For most teams, a simple cadence works best:

• Weekly: monitor the metric when trading conditions or campaign activity change quickly
• Monthly: compare the result against target and prior periods
• Quarterly: reassess assumptions, targets, and the main drivers behind the metric

A practical workflow is to calculate the metric, identify the primary driver of change, test one improvement, and then review the next comparable period before scaling.

Common analysis scenarios

You can use this metric in several practical scenarios:

• monthly performance reviews
• pricing, margin, or cost analysis
• planning and forecasting discussions
• investor, lender, or management reporting

In each scenario, pair the result with the underlying business context so decisions are not made on one number alone.

FAQ extensions

Should I compare this metric across channels?

Yes, but only when definitions and attribution rules are consistent.

How many periods should I review before making changes?

At least 3 comparable periods is a good baseline unless there is a clear data issue or one-off event.

What should I do if this metric improves but profit declines?

Check whether costs, discounts, conversion quality, or downstream profitability changed at the same time.