Degrees of Unsaturation Calculator ToolBy / Degrees of Unsaturation Calculator Degrees of Unsaturation Calculator Enter Number of Carbon (C): Enter Number of Hydrogen (H): Enter Number of Oxygen (O) (Optional): Enter Number of Nitrogen (N) (Optional): Enter Number of Halogen (X) (Optional): Calculate Degrees of Unsaturation Note: Degrees of unsaturation indicate the number of rings and/or double bonds in a compound. DU formula: DU = (2C + 2 – H + N – X) / 2