Resources · Worksheet
Your burn and runway, computed honestly.
Two numbers every founder should be able to produce on demand. Here's the fifteen-minute version.
The formulas
| Number | How |
|---|---|
| Gross burn | Average total monthly cash out (last 3 months). |
| Net burn | Average monthly (cash out − cash in), last 3 months. This is "burn" in the runway sense. |
| Runway | Cash on hand ÷ net burn = months left. Mark the date. |
The worksheet
- Pull the last 3 full months of bank statements — every account.
- Total cash in and cash out per month. Exclude one-offs (fundraise in, equipment out) but note them.
- Average the three months of net flow → your net burn.
- Divide current total cash by net burn → runway in months. Write the actual cash-out date down.
- Recompute monthly. A runway date that never moves closer is the goal; one that jumps around means your burn is lumpy — average over more months.
The traps
- Counting committed-but-unpaid money as cash. A signed contract is not a bank balance.
- Using last month instead of an average. One quiet month flatters burn; one annual payment slanders it.
- Ignoring seasonality. If revenue swings with seasons, model your weakest quarter, not your average one.
Under 6 months of runway is action territory — cut, raise, or change the model. Under 3 is emergency territory. Don't let the spreadsheet find out before you do.
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