Formula
Runway Months = Cash Balance / (Monthly Expenses - Monthly Revenue)
Interactive Widget
Chart
About SaaS Runway Calculator
Runway measures how many months a business can continue operating at its current burn rate before running out of cash, assuming no additional funding is raised and no changes are made to revenue or spending. It is calculated by dividing current cash balance by net monthly burn — the gap between monthly expenses and monthly revenue.
Runway is one of the most consequential numbers for a startup because it sets a hard deadline: it determines when the business needs to either become cash-flow positive, raise additional capital, or cut costs. Most experienced operators track runway monthly rather than calculating it only when it becomes urgent.
Benchmarks
Most investors want to see at least 12 to 18 months of runway at all times, since fundraising itself typically takes 3 to 6 months — a business that waits until it has less than 6 months of runway left is fundraising from a position of weakness.
Runway calculations become misleading if revenue or expenses change materially month to month. A business should recalculate runway regularly using trailing 3-month average burn rather than a single month, since one unusually good or bad month can distort the picture significantly.
Frequently Asked Questions
How much runway should a startup have?
Most investors and experienced operators recommend keeping at least 12 to 18 months of runway at all times. Since fundraising typically takes 3 to 6 months to close, waiting until runway drops below 6 months puts the business in a weak negotiating position.
What happens when monthly revenue exceeds monthly expenses?
When revenue exceeds expenses, net burn is negative — the business is cash-flow positive and technically has infinite runway at the current rate, since it is generating more cash than it spends rather than depleting its balance.
Should I use a single month or an average to calculate burn?
A trailing 3-month average is more reliable than a single month, since one unusually large expense or one exceptionally strong revenue month can distort a single-month calculation significantly. Recalculating runway monthly using the recent average gives an early warning of trend changes.
Want this calculated automatically from real data?
Connect Stripe in read-only mode and Dnoise calculates Runway Months automatically every month — no spreadsheets, no manual entry.
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