How to Calculate Runway: Formula & Examples

Understanding Financial Runway: What It Is and Why It Matters

In the fast-paced world of business and startups, cash is oxygen. No matter how brilliant your product is or how fast your user base is growing, your company cannot survive without money in the bank. This brings us to one of the most critical metrics any founder or financial leader must master: financial runway.

Your runway is the length of time—usually measured in months—that your company can continue to operate before completely running out of cash. Think of it as your countdown clock. Knowing your exact runway allows you to make informed decisions about hiring, marketing spend, fundraising timelines, and pivoting before you find yourself in an emergency.

The Core Formula and Step-by-Step Calculation

Calculating your runway is surprisingly straightforward once you have the right inputs. At its core, the formula is:

$$text{Runway (Months)} = frac{text{Total Cash Balance}}{text{Net Monthly Burn Rate}}$$

To arrive at this number accurately, follow these three steps:

• Step 1: Calculate Your Total Cash Balance. Add up all readily available liquid funds across your business bank accounts, short-term investments, and easily accessible cash equivalents.
• Step 2: Determine Your Net Monthly Burn Rate. Your burn rate is how much cash your business loses each month. To get the net burn rate, subtract your monthly revenue from your total monthly expenses (salaries, software, rent, marketing, etc.).
• Step 3: Divide and Conquer. Divide your total cash balance by your net monthly burn rate to see how many months of life your business has left.

Pro Tip: Always use your Net Burn Rate rather than your Gross Burn Rate. Gross burn is total spending, but net burn accounts for the money flowing back in, giving you a true picture of your cash depletion speed.

A Real-World Example

Let’s put this into practice with a hypothetical startup, NovaTech.

• Cash in Bank: $300,000
• Monthly Revenue: $20,000
• Monthly Expenses: $70,000

First, we calculate NovaTech’s Net Monthly Burn Rate:
$$text{$70,000 (Expenses)} – text{$20,000 (Revenue)} = text{$50,000 Net Burn per month}$$

Next, we apply the runway formula:
$$frac{text{$300,000}}{text{$50,000}} = mathbf{6text{ months}}$$