What Is the Rug Size Calculator?
Choosing the right rug size is one of the easiest ways to make a room feel balanced and complete. Designers usually recommend leaving an even strip of exposed floor around all four sides of the rug. This calculator turns that rule into exact numbers: enter your room length, room width, and the border of bare floor you want to show on each side, and it returns the ideal rug length, width, and total area.
How to Use It
Measure the open floor area of your room in feet. Enter the longer dimension as the room length and the shorter as the width. Then choose how much floor you want to leave exposed on each side — a common range is 8 inches (about 0.67 ft) to 18 inches (1.5 ft). The calculator subtracts twice that border from each dimension and shows the recommended rug size, rounding nothing so you can pick the closest standard rug (such as 5×8, 8×10, or 9×12).
The Formula Explained
Because the border appears on both opposite sides, you subtract it twice from each dimension:
$$\begin{gathered} \text{Rug Length} = \text{Room Length} - 2 \times \text{Border} \\[0.6em] \text{Rug Width} = \text{Room Width} - 2 \times \text{Border} \\[0.6em] \text{Rug Area} = \text{Rug Length} \times \text{Rug Width} \end{gathered}$$
Worked Example
Suppose your living room is 12 ft long and 10 ft wide, and you want a 1.5 ft border of exposed floor. Rug length = $$12 - 2 \times 1.5 = 9 \text{ ft}.$$ Rug width = $$10 - 2 \times 1.5 = 7 \text{ ft}.$$ Area = $$9 \times 7 = 63 \text{ sq ft}.$$ The closest standard rug would be 9×6 or 8×10 depending on your preference.
FAQ
How much floor should I leave exposed? A border of 8–18 inches on each side works for most rooms. Larger rooms can carry a wider border.
Should furniture sit on the rug? In living rooms, at least the front legs of sofas and chairs should rest on the rug for a cohesive look. In dining rooms, the rug should extend about 24 inches beyond the table on all sides.
What if my room is unusual in shape? Measure the main rectangular seating or use area, then apply the same border rule to that zone.
