How to Measure for Carpet

What you need

• A 25 ft tape measure, or a laser measure for larger rooms.
• Graph paper or a phone sketch app.
• Someone to hold the other end of the tape.

Step 1: Sketch the room

Draw the room as seen from above, including closets, alcoves, doorways and any built-ins the carpet goes around. Mark which doorways lead to other flooring. You will write the measurements on this sketch.

Step 2: Measure wall to wall at the widest points

Measure the length and the width from wall to wall, not from baseboard to baseboard. Do it in two or three places, because walls are rarely perfectly parallel, and use the largest number. Round up to the next inch.

Include closets that open off the room, and measure into each doorway to the point under the closed door where the carpet will stop. The usual stop line is the center of the door.

Step 3: Think in roll widths

Carpet is made in rolls, most often 12 ft wide in the US and Canada, sometimes 15 ft, and commonly 4 m in Australia, the UK and Europe. A piece cut from the roll is always full width. A room 11 ft wide still uses a 12 ft wide piece, and a room 14 ft wide needs either a 15 ft roll or two pieces joined by a seam.

Worked example

A 20 × 13 ft basement family room has 260 sq ft of floor, or about 28.9 sq yd. With 10 percent added for trimming:

The 12 ft roll is 1 ft too narrow, so it needs a second strip and a seam. A 13 ft 2 in (4 m) roll covers the room in one piece and is the cheapest on paper, but 4 m is about 13 ft 1½ in, which leaves only about 1½ in across the width for trimming at the walls, which some installers consider too tight; ask yours before you order. The 15 ft roll uses about 4.6 sq yd more than the 13 ft 2 in roll but gives plenty of trimming room. Installers can sometimes reduce the 12 ft figure by cutting fill pieces from offcuts, but only if the pile direction still matches. Try your own room in the carpet calculator, which tests both directions.

Step 4: Plan seams and pile direction

• Pile direction. Carpet fibers lean one way. Every piece in a room must face the same way, or the pieces look like different shades.
• Seam placement. Keep seams out of doorways and heavy walkways. Running them toward the main window makes them less visible.
• Pattern match. Patterned carpet must line up across seams. Add one pattern repeat to each strip.
• Connected rooms. Rooms joined without a door, or a hall and bedrooms, are often planned together so one cut serves two spaces.

Step 5: Measure stairs separately

For each step, measure the width and the depth of the tread plus the height of the riser, including the nose. A typical step needs roughly 18 to 20 in of carpet from front to back. Stairs are cut as separate pieces with the pile running down the flight, so they are usually priced on their own. Winders, landings and open sides add complexity; leave the final count to the installer.

Step 6: Add pad and transitions

Pad does not have a pile direction, so you can order about the floor area: about 29 sq yd for the example room. List each doorway where carpet meets another floor; each needs a transition strip.

Quick conversions

Common measuring mistakes

• Multiplying the floor area by the price. You pay for full roll-width strips, which can be well above the floor area.
• Forgetting closets and doorways. Each closet and each strip into a doorway adds carpet and may change the layout.
• Measuring only one wall. Rooms are rarely square. Measure both ends and the middle.
• Mixing feet and inches. 12 ft 6 in is 12.5 ft, not 12.6 ft.
• Ignoring pile direction. Offcuts can only fill a gap if they face the same way as the main piece.

Before you buy

Most stores measure before quoting, and their measurement sets the order. Your own numbers let you check that quote, compare roll widths and spot a missing closet. Clear furniture before installers arrive, and get help moving heavy pieces.

Frequently asked questions