The depletion allowance is 15% and is calculated on the followup page Enter Your Depletion Information in TurboTax when you enter the oil royalty information.
For example, if you have $1,000 in oil royalties, the depletion allowance is 1,000 x .15 (15%) or $150. You would enter that amount in the box if TurboTax does not calculate it for you.
