How to calculate cash runway in months in Excel and Google Sheets

Step by step

1. 1In cell A1 enter 'Cash Balance ($)' and in B1 enter the current bank balance (e.g. 1200000).
2. 2In cell A2 enter 'Avg Monthly Net Burn ($)' and in B2 enter your 3-month average net burn (e.g. 80000).
3. 3In cell A3 enter 'Runway (months)' and in B3 calculate =B1/B2.
4. 4Optionally, compute the runway end date in B4 with =EDATE(TODAY(),FLOOR(B3,1)) to see the month cash runs out.
5. 5Build a sensitivity table varying burn rate by ±10% and ±20% to understand how quickly runway changes with cost changes.

Tips

• Use net burn (not gross burn) for runway — you want to know how long cash lasts after revenue offsets expenses.
• Model three scenarios: base, optimistic (20% lower burn), and pessimistic (20% higher burn). Share all three with your board.
• Start fundraising when you have 9–12 months of runway remaining. Waiting until 3–4 months creates a distressed negotiating position.

Frequently asked