Designers usually leave 12–18 in (30–45 cm) of bare floor around a room-sized rug. In living rooms the front legs of the sofa and chairs should sit on the rug; in dining rooms the rug should extend at least 24 in beyond the table so chairs stay on it when pulled out.
How to use the Rug Size Calculator
- Rug shape
- Room width
- Room length
- Bare floor border
- Built-in furniture depth (one side)
- Price per area
Results update as you type, and every field accepts the units shown in its menu.
How it works
Choose the rug shape, enter the room size, the border of bare floor you want and the depth of any built-in furniture along one side, and the price per square foot.
Tips
- Use the figures from your own bills and product labels – prices and appliance ratings vary widely.
- Look at yearly totals: small daily costs add up and make it easier to compare options.
- Round quantities up to whole packs, rolls or bulbs when you shop.
- Re-check the numbers when prices change; most results scale directly with the unit price.
Common mistakes to avoid
- Confusing watts (power) with watt-hours or kilowatt-hours (energy).
- Comparing prices without bringing them to the same unit first.
- Ignoring one-off costs such as installation, delivery or replacement parts.
Inputs explained
| Field | What to enter |
|---|---|
| Rug shape | Choose one: Rectangle, Square, Round, Oval … |
| Room width | Units: ft, m, in, cm, yd |
| Room length | Units: ft, m, in, cm, yd |
| Bare floor border | Units: in, cm, ft |
| Built-in furniture depth (one side) | Units: in, cm, ft |
| Price per area | Units: /ft², /m², /yd² |
Example values
How the main result changes when Room width changes and everything else stays at the example values above:
| Room width (ft) | Rug width (ft) |
|---|---|
| 6 | 3 |
| 9 | 6 |
| 12 | 9 |
| 15 | 12 |
| 18 | 15 |
| 24 | 21 |
Formula
Rug width = room width − 2 × border − fixed furniture depth; length similarlyRound rug diameter = smaller dimension − 2 × borderCost = rug area × price per unit areaWorked example
Inputs — Rug shape: Rectangle; Room width: 12 ft; Room length: 15 ft; Bare floor border: 18 in; Built-in furniture depth (one side): 0 in; Price per area: $6 /ft².
Results — Rug width = 9 ft; Rug length = 12 ft; Rug area = 108 ft²; Closest standard size (not larger) = 9 × 12 ft; Rug cost = $648.00.
Frequently asked questions
What size rug for a 12 × 15 room?
Leaving 18 in all round gives a 9 × 12 ft rug – a standard size.
How big should a dining room rug be?
At least 24 in larger than the table on every side.
Should furniture sit on the rug?
In living rooms, at least the front legs of seating should rest on the rug to tie the area together.
What formula does the Rug Size Calculator use?
Rug width = room width − 2 × border − fixed furniture depth; length similarly.