About the Rug Size Calculator
This tool applies the standard interior-design rule for sizing an area rug: leave a consistent border of bare floor visible between the rug's edge and the walls. Enter your room's length and width, plus the border you want to show on every side, and the calculator subtracts that border from each dimension to recommend a rug length, width, and area — plus the closest size actually sold at retail.
The formula
For a room with length L and width W, and a desired floor border B (converted from inches to feet), the recommended rug dimensions are:
- Rug length = L − 2 × B
- Rug width = W − 2 × B
- Rug area = Rug length × Rug width
The border is subtracted twice from each dimension because it applies on both opposite sides of the room. For example, a 14 × 11 ft room with a 15 in (1.25 ft) border gives a rug of about 11.5 × 8.5 ft, or roughly 97.75 sq ft.
Typical border ranges by room
- Living room: 12-18 in of visible floor on each side is the standard guideline, so at least the front legs of major furniture sit on the rug.
- Bedroom: 18-24 in is common, often with the rug extending under the bed and a foot or two past the sides and foot.
- Dining room: the convention is different — measure 24-30 in beyond the edge of the table itself (not the room walls) so chairs remain on the rug even when pulled back from the table.
- Hallway or entry: narrower borders of 4-8 in are typical, since runners are sized to fit a constrained walkway.
Rounding to a standard size
Area rugs are manufactured in a limited set of sizes — commonly 3x5, 4x6, 5x7 or 5x8, 6x9, 8x10, 9x12, and 10x14 ft. The calculated rug dimensions rarely match one of these exactly, so the calculator also reports the closest standard size (checking both orientations) as a practical shopping target.