How to Measure the Stairs for Carpets: a Step by Step Guide

Simplifying the process of measuring for Stair Carpets

Whether you’re looking to refresh your staircase with a plush new carpet or planning to install a durable runner, knowing how to measure for a stair carpet accurately is crucial. With this step-by-step guide, you can calculate exactly how much stair carpet you need, ensuring your project goes smoothly while minimising waste.

What to Measure for Stair Carpet

Why Accurate Measurements Matter for Stair Carpets

Purchasing too little carpet could result in delays and sometime results in mismatched dye lots if you need to order more. On the other hand, buying too much leads to unnecessary expense. Accurately measuring your stairs ensures you get the perfect amount of material for your staircase.

Tools You’ll Need

Before you start, gather the following: Measuring tape Pen and paper (or a digital device to record measurements) Calculator Masking tape (optional for marking areas)

Types of Staircases

Before measuring, identify the type of staircase you have, as it will affect your calculations:

1. Straight stairs - Uniform size and shape, the easiest to measure.
2. Winder stairs - Feature angled steps that require extra attention.
3. Curved or spiral stairs - More intricate shapes requiring precise measurements for each step.
4. Stairs with landings - Include flat sections that need separate measurements.

Step-by-Step Measuring Guide

 

Step 1: Measure the Tread (Step Depth)

Place your measuring tape at the front edge (nose) of the step and extend it to the back where the step meets the riser (vertical section). Record the measurement in centimetres or inches (Most websites are now meters and centimetres)

Step 2: Measure the Riser (Step Height)

Measure from the top edge of one step down to the bottom where it meets the next step. Record this measurement as the riser height.

Step 3: Measure the Width

Measure the width of the step from one side to the other. This is especially important if you’re carpeting the entire staircase rather than using a runner.

Step 4: Multiply for One Step

To calculate the carpet needed for a single step, use the formula: Tread + Riser + Overhang (if applicable)

For example:

• Tread = 25cm 
• Riser = 18cm
• Overhang = 2cm Total per step = 25 + 18 + 2 = 45cm

Step 5: Measure the Number of Steps

Count the total number of steps on your staircase. For landings, measure them separately as a rectangular area (length x width).

Step 6: Calculate Total Carpet Needed

Multiply the total measurement for one step by the number of steps. Don’t forget to add the carpet required for any landings. Then, convert your measurements to square metres or square feet, depending on your supplier’s preferred units.

Pro Tip: Always add an extra 10% to your total measurement to account for cutting and fitting adjustments.

Example Calculation

Let’s say you have 12 straight steps, each with:

• Tread = 25cm 
• Riser = 18cm
• Width = 80cm

1. Calculate the total length for one step: 25cm (tread) + 18cm (riser) = 43cm
2. Multiply by the number of steps: 43cm x 12 = 516cm (5.16m)
3. Add the width: 5.16m x 0.8m = 4.13 square metres
4. Include a 10% buffer: 4.13m² x 1.10 = 4.54m²

You would need approximately 4.54 square metres of carpet for this staircase.

You can also use the following useful website that you input your measurements into and will do the calculation for you: Stair Carpet Calculator

Tips for Measuring Winder or Spiral Stairs

1. Measure each step individually, as dimensions vary.
2. For curved steps, measure the widest part of the tread and riser.

Don’t forget the landing

Measuring the landing or hallways carpet is just like measuring any other room, get a piece of paper and draw out the room, then measure end to end the width making sure you include doorways and any covings, then do the same for the length. We always recommend going over. For more information you can check out our measuring guide here: or blog here: How to Measure Carpet 

Final Checks Before Ordering

• Double-check all measurements.
• Consult your carpet supplier for advice on pile direction and additional material for pattern matching.
• Ensure the carpet you choose is suitable for stairs—durability and safety are key considerations.

Common Mistakes When Measuring Stairs for Carpet

Measuring stairs is straightforward, but small mistakes can lead to ordering too much or too little carpet. Before placing your order, avoid these common errors:

• Forgetting to include the stair nosing (overhang)
  
• Measuring only one step when the staircase has different-sized steps
  
• Not measuring landings separately
  
• Forgetting to add a trimming allowance
  
• Mixing centimetres and metres during calculations

Expert Tip: Measure every step individually if your staircase includes winders or curved sections. Even small differences can affect how much carpet you need and help reduce unnecessary waste.

Conclusion on Measuring for Stair Carpets

Measuring your stairs for carpet doesn’t have to be daunting. With careful planning and accurate measurements, you can confidently order the right amount of carpet for your staircase. If you’re unsure, consider consulting a professional fitter to verify your measurements. For premium-quality stair carpets and runners in the UK, visit Carpets-Online.co.uk for an extensive selection to suit every style and budget!

Frequently Asked Questions

Question- : How do I measure stairs for carpet?

Answer- : To measure stairs for carpet, measure the depth of each tread, the height of each riser, and the width of your staircase. Add the tread and riser measurements together, multiply by the number of steps, then include any landings and a small allowance for trimming and fitting.

Question- : Should I measure every stair individually?

Answer- : If all your stairs are the same size, measuring one step is usually enough. However, for winding, curved, or older staircases, it's best to measure each stair individually, as the dimensions may vary.

Question- : How much extra carpet should I allow for stairs?

Answer- : It's a good idea to allow an extra 5% to 10% of carpet to cover trimming, fitting, and any unexpected measuring differences. This helps ensure you have enough carpet for a professional installation.

Question- : What is the most common mistake when measuring stairs for carpet?

Answer- : One of the most common mistakes is forgetting to include the stair nosing (the front edge of each step) or failing to measure landings separately. Double-checking your measurements before ordering can help avoid costly mistakes.

Question- : Which type of carpet is best for stairs?

Answer- : Twist pile, polypropylene, and other hard-wearing carpets are popular choices for stairs because they offer excellent durability, resist everyday wear, and are easy to maintain in busy homes.

Question- : Can I order carpet samples before measuring?

Answer- : Yes. Ordering carpet samples before making your final decision allows you to compare colours, textures, and materials in your home. Once you've chosen your favourite sample, you can measure your stairs accurately and order the correct amount of carpet.