Cash Runway Calculator
Calculate months of runway and your zero-cash date from cash and monthly burn, with best, base, and downside scenarios side by side.
How do I calculate cash runway?
Divide your current cash balance by your average monthly net burn. If you hold $2,400,000 and burn $200,000 a month, you have 12 months of runway. Net burn is the real number to use (cash out minus cash in, not gross spend) and it should be averaged over at least three months, because a single month distorted by an annual insurance payment or a large collection will give you a runway figure that is confidently wrong in either direction.
How to use this tool
- 1
Enter your cash position
Use cash and cash equivalents you can actually access: exclude restricted cash and undrawn credit facilities.
- 2
Set your monthly net burn
Average the last three months of cash out minus cash in, so one unusual month does not skew the answer.
- 3
Read the scenarios
See base, downside, and improved cases side by side, with the zero-cash date for each.
Gross burn and net burn produce very different runways
Most runway mistakes are definitional, not arithmetic. Four distinctions decide whether your number is usable.
Gross burn vs net burn
Gross burn is total cash going out. Net burn subtracts cash coming in. A company with $400,000 of monthly costs and $250,000 of collections has a $150,000 net burn: using gross burn here would understate runway by more than half.
Accrual loss vs cash burn
Your P&L loss is not your burn. Depreciation, accrued but unpaid bonuses, and deferred revenue all break the link between reported loss and cash movement. Runway is a cash question and must be calculated from cash.
Averaged burn vs last month
One month is not a trend. Annual insurance renewals, quarterly tax payments, and semi-annual bonus runs create months that look nothing like the underlying rate. Average at least three, and note which months contain a one-off.
Available cash vs total cash
Restricted cash, customer deposits held in trust, and cash sitting in an entity you cannot easily move it out of are not runway. Undrawn credit is optionality, not cash: track it separately rather than adding it to the balance.
Numbers to sanity-check against
These thresholds are common planning conventions in US venture-backed and growth-stage companies, not a rule. A profitable, slow-growth business can operate comfortably at levels that would be alarming for a company raising every 18 months.
Why your real runway moves every month
A single average burn rate assumes next month looks like last month. It rarely does. Your actual runway bends around collections timing, the hire starting in March, the annual software renewals stacked in Q1, and the two customers who always pay 20 days late. Building the version that accounts for all of that means a rolling 13-week cash forecast rebuilt from source data every week, which is precisely the work that gets skipped when the person who would do it is answering board questions instead.
See how DataWyse answers thisQuestions finance teams ask about this tool
What is a good cash runway?
For a growth-stage company that expects to raise again, 18 or more months is comfortable and 12 months is the point where a plan should already be in motion. Below 6 months, options narrow fast. A profitable business with predictable collections can run comfortably on far less, because runway matters most when you are dependent on outside capital.
Should I use gross burn or net burn?
Net burn, for runway. Gross burn is useful for understanding your cost base and for stress-testing what happens if revenue stops entirely, but runway answers the question of how long your cash lasts given the business as it actually operates, and that includes money coming in.
Does a credit line count toward runway?
Track it separately. Undrawn credit is real optionality, but facilities carry covenants and can be reduced or withdrawn exactly when conditions deteriorate. Report runway on cash, then note available credit alongside it rather than adding the two together.
How often should runway be recalculated?
Monthly at minimum, weekly below 12 months of runway. The number moves with every large collection and payment, and the decisions it drives (hiring, spend approvals, fundraise timing) get harder the later you see the change.
Why does my runway differ from my P&L loss?
Because the P&L is accrual-based and runway is cash-based. Depreciation reduces reported profit without moving cash. Deferred revenue takes cash before it appears as revenue. Accrued bonuses hit the P&L months before they are paid. The two numbers answer different questions and should not match.
Is this tool really free?
Yes. No signup, no email required, no usage limit. It runs entirely in your browser: nothing you type is uploaded to a server or stored anywhere. We build these because the people who find them useful are the people who eventually need a financial analyst that works the same way.
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