Here is the solution for those who are looking for a twin-size mattress but need more leg space; the standard length is 74" when a twin-size XL is 80". An extra 6 inches of comfort, we like that! But if you want more space from every side, whether it is for you or your kid, a full-size mattress is what you need! Anyway, they grow up so quickly! With a cute headboard or bed base, you will create a new safe haven.