Rug Size Calculator

Find the ideal rug size for your room by leaving an even border of bare floor around the edges.

Result

310 cm
210 cm
6.51 m²

How it is calculated

All three inputs are in centimetres. The tool takes the room length and width and subtracts the bare-floor border from both ends of each side: rug length = room length − 2 × border and rug width = room width − 2 × border. The area is rug length × rug width / 10,000, converting cm² to m², rounded to two decimals. If you leave the border empty (or enter a negative number), 45 cm is used; 0 is accepted and gives a wall-to-wall rug. If the border is so large that either rug side becomes zero or negative, there is no result. The tool returns the exact size, not a stock size sold in shops.

Worked example

The room is 400 cm long and 300 cm wide, and you want a 45 cm border of bare floor all around. The border is taken off twice per side, 2 × 45 = 90 cm. The rug length is 400 − 90 = 310 cm and the width is 300 − 90 = 210 cm. The area is 310 × 210 = 65,100 cm², which divided by 10,000 is 6.51 m². A 310 × 210 cm rug leaves an even 45 cm strip of floor on every side.

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Common mistakes

  • Entering the room size in metres or feet. The fields are in centimetres, so a 4 m room is 400; typing 4 gives a negative rug size and no result.
  • Entering the border for one side only and forgetting it applies on both ends. The tool already subtracts it twice, so a 45 cm border removes 90 cm in each direction.
  • Measuring wall to wall including alcoves or built-in furniture. Measure the open floor you actually want to frame.
  • Treating the result as a product size. Rugs are sold in set sizes, so you will usually pick the nearest size that is slightly smaller, which makes the border wider.
  • Leaving the border empty and not noticing that it defaults to 45 cm, which is too much for a small room and can leave no result.

About this calculator

This calculator works backward from room size: subtracting twice the desired floor border from each room dimension gives the rug size that leaves an even margin of bare floor visible on all sides — the look most interior designers aim for rather than a rug that runs edge-to-edge or floats too small in the middle.

Interior designers typically recommend a 10-20 cm (4-8 in) border in small rooms and up to 45 cm (18 in) in larger living rooms, and use this same subtraction to check that all the furniture's front legs can still sit on the rug. Homeowners shopping for a rug use it to avoid the common mistake of buying one sized only to the coffee table instead of the room.

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Comments (1)

  • Editorial team

    The result is the exact rug that fits your border, and shops sell fixed sizes. Pick the nearest stock size and work backwards: a 300 by 200 cm rug in a 400 by 300 cm room leaves 50 cm of bare floor on every side. In living rooms, check that at least the front legs of the sofa land on the rug. What rooms and rug sizes are you shopping for?

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