A bounded scenario, not a cash forecast. Enter operating cash flows only and verify whether financing, taxes, one-time costs, or owner draws belong in your assumptions.
Calculation details
Planning estimate only. Platform fees, taxes, payment costs, and policies can change; verify current terms before pricing.
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More options
What does this calculator estimate?
Cash flow runway calculator: turn burn rate and cash balance into months of runway so you know when your startup needs funding. Free, runs in your browser.
How this calculator works
Formula
Starting cash is updated month by month by adding modeled revenue and subtracting modeled expenses; each may compound by its entered monthly change. Runway is the first month ending cash reaches zero or below.
Worked example
$10,000 starting cash with $2,000 monthly revenue and $3,000 monthly expenses reaches zero at month 10 when both remain constant.
Assumptions to verify
- Revenue and expenses change at constant monthly rates after month one.
- Financing, taxes, owner draws, and one-time cash flows are excluded unless included in inputs.
- A result beyond the horizon means only that cash stayed positive during the modeled months.
Frequently asked questions
Is this a forecast?
No. It is a bounded scenario using constant assumptions.
What does beyond the horizon mean?
Cash remained above zero during the selected months; it does not mean unlimited runway.
What is operating break-even?
The first modeled month in which revenue is at least expenses before financing and excluded cash flows.
Cite this tool
BoringToolsKit. “Cash-Flow Runway Calculator.” boringtoolskit.com/cash-flow-runway-calculator/ (reviewed July 2026). Free to reference in articles, syllabi, and answer posts with a link.
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