Burn Rate and Runway Calculator
Compare cash runway under direct net burn or gross outflows minus cash inflows. See four burn scenarios and a cash trajectory capped at 60 months.
How the runway scenario works
Enter available cash and choose a burn mode. In gross mode, enter monthly cash outflows and cash inflows. In direct net mode, enter the monthly net burn amount itself, which may be positive, zero, or negative.
For positive net burn, runway is the cash balance divided by net burn. Zero net burn leaves the balance flat. Negative net burn means the modeled cash balance grows because entered inflows exceed outflows.
Review the four scenario multipliers and the monthly cash balance table. Runway can be fractional because it divides cash by monthly net burn. The trajectory shows up to 60 months and is capped at zero after modeled exhaustion.
The calculation assumes each monthly amount repeats unchanged. Use it to compare stated inputs, not as a forecast of collections, bills, financing, or a funding date.
Step by step
- Enter available cash and select gross outflows or direct net burn.
- In gross mode, enter monthly outflows and cash inflows. In direct net mode, enter the signed net burn amount.
- Compare runway, the scenario table, and the modeled cash trajectory.
Worked example
Select gross mode and enter cash of 100,000 USD, monthly cash outflows of 20,000 USD, and collected cash inflows of 15,000 USD.
Net burn is 5,000 USD per month, so 100,000 USD divided by 5,000 USD gives 20 months of modeled runway. The cash inflow needed to match the entered outflows is 20,000 USD. This assumes the entered monthly amounts stay constant.
When to use this calculator
Use this calculator to divide available cash by a stated monthly net burn, or to derive net burn from gross cash outflows and cash inflows.
Compare the scenarios when testing different constant net burn amounts. For actual cash planning, also account for bill timing, collection dates, financing, and changing balances.
Common input and reading errors
Do not enter accounting revenue as cash inflow unless it represents money received in the same monthly period. Receivables and cash collections can occur at different times.
Do not interpret a finite runway when net burn is zero or negative. Under the constant inputs, cash is flat or growing, so there is no finite exhaustion month.
Runway formulas
Gross mode:
net burn = monthly gross cash outflows − monthly cash inflows
Direct net mode:
net burn = entered monthly net burn
If net burn > 0: runway months = cash on hand ÷ net burn
If net burn = 0: cash stays flat and runway has no finite exhaustion month
If net burn < 0: modeled cash grows and runway has no finite exhaustion month
Scenarios use 75%, 100%, 125%, and 150% × net burn.
The model treats entered monthly amounts as constant. Cash inflows are amounts received during the month, not necessarily accounting revenue. Direct net mode cannot identify gross outflows from net burn alone, so the gross cash inflow target is unavailable in that mode.
Scope and limitations
This calculator applies constant monthly amounts. It does not model changing expenses, collection delays, financing, restricted cash, or the timing of individual payments. Cash inflows are not necessarily accounting revenue. Direct net mode cannot infer gross outflows or a gross cash inflow target. Scenario multipliers are descriptive comparisons, not recommendations. The trajectory is capped at 60 months and displays zero after modeled exhaustion. It is not a bank balance forecast or funding schedule. All amounts must be finite and within the supported numeric range.
Key terms
- Gross cash outflows
- Monthly cash outflows before subtracting cash inflows. In this tool, gross outflows are entered only in gross mode.
- Net burn
- Monthly cash outflows minus cash inflows in gross mode, or the signed monthly amount entered directly in net mode.
- Runway
- Available cash divided by positive net burn. Zero or negative net burn has no finite exhaustion month under constant inputs.
Related analysis
Compare this runway scenario with a separate break even calculator when you want to model revenue needed to cover fixed costs. The tools answer different questions.
MRR Runrate projects recurring revenue using its own growth assumptions. This calculator models cash balance under a selected net burn amount or gross outflows and cash inflows.
FAQ
How is runway calculated?
Runway is cash on hand divided by positive net burn. In gross mode, net burn is monthly cash outflows minus monthly cash inflows. In direct net mode, the entered burn is used as given.
What is the difference between gross and net burn?
Gross outflows are monthly cash paid before inflows. Net burn is the signed difference after cash inflows. A negative net burn means the modeled cash balance grows during the month.
What do the burn scenarios show?
The table applies 75%, 100%, 125%, and 150% multipliers to the selected net burn. These are comparison scenarios, not recommended cost cuts. When net burn is zero or negative, none has a finite cash exhaustion time.
What does the cash inflow target show?
In gross mode, it shows the monthly cash inflow amount that would match the entered gross cash outflows. In direct net mode, gross outflows are unknown, so this value is unavailable.
How far does the cash trajectory extend?
The table displays modeled cash balances for up to 60 months. It uses constant monthly burn and inflows, and floors the displayed balance at zero after modeled exhaustion. It does not predict payment dates or future funding.
Related tools
Use a break even analysis for a separate estimate of revenue needed to cover costs. Use MRR Runrate for a recurring revenue growth scenario; it does not calculate cash runway.