We need help finding the right excel financial function. We have tried FV, NPV, and PV, and none seem appropriate. Here is our scenario: we own a parcel of land which we rent to a tenant. The tenant pays us monthly rent of $4000.00. The tenant wants to buy the land. We need to know how much to ask for a purchase price. The assumptions we can make are that the current lease expires in 2035 and that the interest rate will be a constant 1%.  we need to know what should be the minimum asking price such that it would be more favorable to sell rather than to continue leasing, to maintain us getting the $4k per month for next 20 years.

Another way to phrase our goal: how much money would someone need to put into a savings account earning 1% interest per annum in 2015, such that we could withdraw $4k each
month through 2035.

The PV function should do it/

A yearly interest rate of 1% corresponds to a monthly rate of (100%+1%)^(1/12)-100%.

The number of periods is 20*12.

The formula =PV((100%+1%)^(1/12)-100%,20*12,4000) returns -870,149.43

The minus signifies that you pay (you put money in a savings account)

So you'd have to ask at least $870,149.43 for the land if you want to get $4000 or more interest per month from the savings account.