In short, coil gauge counts pertain to a mattress’ firmness, while the number of coils in a mattress dictates its durability. Most innerspring mattresses have a coil gauge between 12 and 15, with more forgiving mattresses having a gauge of 14 to 15 and firmer ones having around 13. On the other hand, the optimal coil count for memory foam mattresses is between 800 and 1,000 for a queen size.