Free Rug Size Calculator

A rug size calculator is a practical tool that helps you determine the ideal rug dimensions for any room while also estimating the total cost. Whether you are furnishing a living room, dining area, hallway, or bedroom, this free online rug dimensions and cost tool takes the guesswork out of choosing the right size. By selecting the rug shape – rectangle, square, runner, circle, oval, or octagon – and specifying how much bare floor you want to leave around the rug, you instantly get a custom rug size. The calculator also suggests the nearest standard rug size available in the market, making it easy to compare options and stay within budget.

How to Use the Rug Size Calculator

Start by choosing the rug style that matches your space. The tool supports six shapes: rectangle, square, runner, circle, oval, and octagon. Next, define the bare floor perimeter – the margin of uncovered floor you wish to leave between the rug and the walls. The default is 1.5 feet on all sides, but you can adjust this value to suit your preference.

Enter the room width and length in the fields provided. For instance, a room measuring 12 ft × 16 ft shows a total area of 192 sq. ft. If the room contains fixed obstructions such as a fireplace or a built‑in cupboard, input their width and length as extrusions. The calculator automatically subtracts these from the available floor space.

After all inputs are set, the tool displays the custom rug length, width, and area. With a 1.5‑ft uncovered margin in a 12 ft × 16 ft room, the recommended custom rectangle rug is 10.5 ft × 14.5 ft (approximately 152.2 sq. ft). If you prefer a ready‑made rug, the calculator shows the closest standard size – in this case, 10 ft × 14 ft.

The rug cost estimator works by multiplying the rug area by the price per square foot (or per square meter) you enter. The total cost updates instantly, helping you control your budget.

Manual Rug Size Calculations for Different Shapes

If you want to verify or compute sizes manually, the same formulas apply. The general rule is to determine the rug dimensions by subtracting the uncovered margin and any extrusions from the room dimensions.

Rectangle Rug

For a rectangular rug:

$$\begin{aligned} W_{\text{rug}} &= W_{\text{room}} - W_{\text{extrusion}} - U_{\text{uncovered}} \\ L_{\text{rug}} &= L_{\text{room}} - L_{\text{extrusion}} - U_{\text{uncovered}} \\ \text{Area} &= W_{\text{rug}} \times L_{\text{rug}} \end{aligned}$$

Example: A dining room 15 ft × 10 ft, with a 1‑ft fireplace extrusion on the width and a 1.5‑ft uncovered margin all around.

$$\begin{aligned} W_{\text{rug}} &= 15 - 1 - 1.5 = 12.5\ \text{ft} \\ L_{\text{rug}} &= 10 - 0 - 1.5 = 8.5\ \text{ft} \\ \text{Area} &= 12.5 \times 8.5 = 106.25\ \text{sq. ft}. \end{aligned}$$

Square Rug

For a square rug, use the shorter side of the room after adjustments.

Example: A living room 12 ft × 14 ft, leaving 2 ft uncovered on all sides.

$$\begin{aligned} W_{\text{rug}} = L_{\text{rug}} &= 12 - 0 - 2 = 10\ \text{ft} \\ \text{Area} &= 10 \times 10 = 100\ \text{sq. ft}. \end{aligned}$$

In square inches: $100 \times 144 = 14,400\ \text{sq. in}$.

Runner Rug

Runner rugs typically have a width between 2 and 3 ft and are used in hallways or kitchens. Multiply the desired runner width by the floor length.

Example: A kitchen with a 12‑ft floor length and a 3‑ft runner width:

$$\text{Area} = 3 \times 12 = 36\ \text{sq. ft}.$$

Circle Rug

A circular rug uses the shorter adjusted room side as its diameter.

$$\text{Area} = \pi \left( \frac{D}{2} \right)^2$$

Example: A space 5 ft × 7 ft, with no margin, so the diameter is 5 ft.

$$\text{Area} \approx 3.14159 \times \left( \frac{5}{2} \right)^2 \approx 19.63\ \text{sq. ft}.$$

In square inches: $19.63 \times 144 \approx 2827\ \text{sq. in}$.

Oval Rug

The area of an oval rug is:

$$\text{Area} = \pi \times \frac{W_{\text{rug}}}{2} \times \frac{L_{\text{rug}}}{2}$$

Example: A dining room 15 ft × 10 ft, with 3 ft uncovered on all sides and no extrusions.

$$\begin{aligned} W_{\text{rug}} &= 15 - 0 - 3 = 12\ \text{ft} \\ L_{\text{rug}} &= 10 - 0 - 3 = 7\ \text{ft} \\ \text{Area} &= \pi \times \frac{12}{2} \times \frac{7}{2} \approx 65.97\ \text{sq. ft}. \end{aligned}$$

Octagon Rug

For an octagonal rug, start with the shorter adjusted room side (S). The side of the octagon is approximately $0.4142 \times S$, and the area is:

$$\text{Area} = (0.4142 \times S)^2 \times 4.8284$$

Example: A space 6 ft × 6 ft, no margin.

$$\text{Area} = (0.4142 \times 6)^2 \times 4.8284 \approx 29.8\ \text{sq. ft}.$$

Rug Pad Size

A rug pad keeps the rug from slipping and adds cushioning. To get the right pad dimensions, subtract 1 inch (2.5 cm) from each side of the rug. For a 5 ft × 8 ft rug, the pad should be approximately 4 ft 11 in × 7 ft 11 in.

Standard Rug Sizes

If you prefer not to order a custom rug, here are the most common ready‑made sizes for each shape (all measurements in feet):

Shape	Standard Dimensions (ft)
Rectangle	5×3, 6×4, 8×5, 9×6, 10×8, 12×9, 14×10, 15×12, 18×12
Oval	Typically the same ranges as rectangle
Square	4×4, 6×6, 8×8, 10×10, 12×12
Circle	4′ d, 6′ d, 8′ d, 10′ d, 12′ d
Octagon	4×4, 6×6, 8×8, 10×10, 12×12
Runner	6×2, 8×2, 10×2, 8×2.5, 10×2.5, 12×2.5, 10×3, 12×3, 15×3

If none of these standards fit your space, a custom‑cut rug is always an option. The rug size calculator provides both the custom dimensions and the nearest standard match, allowing you to choose what works best for your room and budget.