Even though an RV mattress might go by the same names as household ones—twin, queen, etc.—RV mattresses are different sizes. Most of the time, they’re slightly smaller. For instance, an RV twin is 28 by 75 inches, while its standard mattress counterpart is 38 by 75 inches. An RV queen (or “short queen”) is 60 by 75 inches, while a standard queen is 60 by 80 inches. An RV king is 72 by 75 inches, while the standard version is 76 by80 inches. The one exception to the slightly-smaller rule is double or full-sized mattresses. Both standard and RV-specific versions are roughly 53 by 75 inches.