Question: do two singles make a king?
Answer: 2 regular twins do NOT equal a king (but it can work). I had always heard that two twins equal a king in size and this is true with 2 twin XL (extra long) mattresses (like colleges) but NOT with regular twin mattresses. 2 regular twin mattress are the same width but shorter in length than a king by 5″ (76″x75″).