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Rug size calculator
Enter your room dimensions and sofa length. Get the right standard rug size — 5×8, 8×10, 9×12, or 10×14 — with a top-down diagram and the rationale behind the choice. Built on the same sizing rules interior designers use.
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<iframe src="https://plopit.app/tools/rug-size-calculator?embed=1" width="100%" height="720" frameborder="0" title="Rug size calculator by PlopIt"></iframe>How the calculator decides
Two rules carry most of the work. Front legs on is the safe default: the rug must extend at least 6 inches past each side of the sofa and reach under the front legs of any chairs across. All legs on is more intentional but needs 18-24 inches of rug visible past every furniture leg — usually only feasible in larger rooms.
For the room itself, the rug should leave at least 12 inches of bare floor between its edge and every wall. Push the rug all the way to the wall and the room reads smaller; leave too much margin and the rug stops anchoring the seating area. The calculator finds the smallest standard size that meets both constraints, then flags warnings if the room is too tight or the sofa is too long.
Standard sizes covered: 4×6, 5×7, 5×8, 6×9, 8×10, 9×12, 10×14, 12×15 (feet). Metric equivalents are shown in the result. Sizes outside this range — runners, jumbo 12×18 — are uncommon enough that we don't recommend them by default.
Common rug-size mistakes
- Sizing down to save money.A 5'×7' under a full sofa is the classic mistake — looks like a placemat. A plain larger rug beats an ornate smaller one.
- Centring on the room, not the seating. Centre the rug on the seating arrangement, not the geometric centre of the floor. Matters most in open-plan rooms.
- Forgetting the coffee table.The coffee table should sit fully on the rug. Half-on, half-off and the rug isn't doing its job.
- Skipping the visual check. Size is half the question. Pattern density and colour against your real wood floor are the other half — and only a preview can show those.
Frequently asked questions
What size rug do I need for my living room?
For a standard living room (12×15 ft) with an 84-inch three-seat sofa, an 8×10 ft rug is the sweet spot — front legs of the sofa and chairs across all sit on the rug, with 12-24 inches of bare floor margin to the walls. Use the calculator above for your specific dimensions.
Should the rug go under the sofa or in front of it?
Two of three legs minimum. The standard convention is 'front legs on' — the rug extends at least under the front legs of every major seat. 'All legs on' is more intentional but needs a larger rug. 'Floating in front' (no legs on) reads disconnected and is the most common rug-size mistake.
How much rug should show past the sofa?
At least 8 inches past each side of the sofa for front-legs-on layouts, and 18-24 inches past each side for all-legs-on. Less than that and the rug looks too small for the seating; more and the rug starts crowding the walls.
How far should the rug be from the wall?
Leave 12-24 inches (30-60 cm) of bare floor between the rug edge and the wall. Pushing the rug all the way to the wall makes the room read smaller and looks like the rug is the wrong size. In open-plan rooms the buffer can be larger because the rug also defines the seating zone.
Is a 5×7 rug too small for a living room?
Almost always. A 5×7 under a full sofa shows only 10-12 inches of rug on either side and reads like a placemat. If the budget rug is too small, pick a plain larger rug over an ornate smaller one — size has more impact on how the room reads than pattern does.
Does this calculator work for bedrooms?
This version is sized for living rooms. For bedrooms, use the bedroom rug guide — the sizing rule changes because the rug is positioned relative to the bed (24+ inches past each side), not the sofa.