In order to select the ideal comforter size, buyers should put into consideration the measurements of their mattresses. For instance, comforters are available in the exact standard sizes as the mattress - Twin, King, Queen, Full, King, California King, etc. Just remember, dimensions might vary from one brand to another. So, just to be more precise, compare the sizing charts provided by the comforter manufacturer with the dimensions of your mattress to ensure you're buying a perfect fit.