A bed frame’s outside measurements are usually larger than the mattress it holds. The side rails, headboard, footboard, and decorative edges add width or length, and each design differs. Use a product’s listed overall dimensions when checking whether it will fit your room; mattress size alone is not enough.
For the mattress measurements themselves, see our Twin Mattress Dimensions and King Bed Dimensions guides.
The following measurements are examples from IKEA’s MALM bed-frame line. They show how a particular frame’s exterior footprint compares with the mattress it is designed to hold; they are not universal frame standards.
| Frame size | Overall width | Overall length | Mattress width | Mattress length |
|---|---|---|---|---|
| Twin | 44 1/8 in | 78 3/8 in | 38 1/4 in | 74 3/8 in |
| Queen | 66 1/8 in | 83 1/8 in | 59 7/8 in | 79 1/2 in |
| King | 82 1/4 in | 83 1/8 in | 76 in | 79 1/2 in |
Sources: IKEA MALM twin frame, IKEA MALM queen frame, and IKEA MALM king frame.
Measure the frame at its widest and longest points, including a headboard or footboard that projects beyond the rails. Leave room for walking paths, drawers, and doors to open. If you are planning a queen bed in a specific room, our 10×12 bedroom layout guide covers another part of the fit calculation.
Before ordering, confirm the exact “overall dimensions” on the manufacturer’s listing: frames of the same nominal mattress size can have different footprints.