How to Measure Stairs for Carpet (With Simple Calculator)

Thinking of carpeting your stairs? Before you buy that plush runner or durable twist pile, you’ll need to measure your stairs accurately. Whether you’re doing it yourself or preparing for a fitter, here’s how to calculate the amount of carpet you’ll need.

“Measure twice, cut once — especially when it comes to stairs.”


Why Measuring Stairs Matters

Incorrect measurements can result in:

  • Buying too much carpet and wasting money

  • Coming up short and delaying installation

  • Visible seams or unsafe joins

Let’s make sure that doesn’t happen.


Tools You’ll Need

  • Tape measure (rigid or cloth)

  • Calculator (or use our tool below)

  • Notebook or phone to record values


What to Measure

For Straight Stairs:

Measure the following:

  • Tread depth (horizontal part of the stair)

  • Riser height (vertical part of the stair)

  • Number of steps (including landings)

  • Stair width (if you’re carpeting the full width)

Example: 10 stairs with 9″ treads and 7″ risers = (10 x (9 + 7)) = 160″ = approx. 13.3 ft of carpet needed (plus waste).

For Winder or Curved Stairs:

These need a template or pro assessment, but a rough estimate can be done by measuring the longest tread and riser and multiplying as above.

Stair Carpet Calculator






Pro Tips

  • Add 10% extra for cutting, waste, and errors

  • Don’t forget the landing if it’s being carpeted too

  • Use a gripper rod and underlay for a neater finish


What About Windows?

While you’re improving your home’s interior, don’t forget the finer details. Want to know the right way to measure windows for a sleek blind installation?

👉 Check out our How to Measure Windows for Blinds guide for expert help.


Final Thoughts

Measuring stairs for carpet is easier than most people think — and with the calculator above, you can confidently order just the right amount of material. Save time, money, and hassle.

Have a question or want help measuring trickier staircases? Drop us a message — we’re happy to help!

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