Yes, there is a function in Excel that can help you calculate how long funds will last based on the given parameters. The function is called "NPER" and it calculates the number of periods required to pay off a loan or investment based on a constant payment and a constant interest rate.

To use the NPER function to calculate how long funds will last, follow these steps:

1. Open a new Excel worksheet and enter the following information in cells A1 to A3:
   - A1: $1,000,000 (initial amount of money)
   - A2: 4% (annual interest rate)
   - A3: -$50,000 (yearly withdrawal amount, entered as a negative value)
   
2. In cell A4, enter the following formula:
   Code:

   =NPER(A2/12,A3,A1)

3. Press Enter to calculate the number of periods required to exhaust the funds.

The NPER function takes three arguments:
- rate: the interest rate per period (in this case, the annual interest rate divided by 12 to get the monthly interest rate)
- pmt: the constant payment made each period (in this case, the yearly withdrawal amount entered as a negative value)
- pv: the present value of the investment (in this case, the initial amount of money)

The result of the NPER function is the number of periods required to exhaust the funds, which is expressed in months. To convert this to years, divide the result by 12.

For example, if the result of the NPER function is 20 years, 4 months, you can divide the number of months by 12 to get the number of years: 20.33 years.

So in this example, the funds will last approximately 20 years and 4 months if the interest rate remains constant and the yearly withdrawal amount is $50,000.