Scuba MOD Calculator can be used to find the Maximum Operating Depth (MOD) at the provided Partial Pressure of Oxygen (PpO2) with various Fractions of Oxygen (FO2%). Just enter values for "Fraction of Oxygen (FO2)" and "Partial Pressure Oxygen (PpO2)". Planning to upgrade your certification level? Want to brush up on your dive theory before you take the final exam?