How Much Carpet for 13 Stairs in Metres

Carpet requirement for a 13-step staircase depends on stair dimensions, installation style and roll width. This article explains how to measure, calculate and order the right amount of carpet in metres, with practical examples, waste allowances and installation considerations for American homes. Estimating correctly avoids costly returns and unsightly seams.

Scenario	Typical Tread (m)	Typical Riser (m)	Total Linear Metres Needed (Incl. 15% Waste)	Notes
Continuous Run	0.28	0.18	6.9 m	Single length down stairs, one roll width needed
Separate Treads & Risers	0.28	0.18	8.5–9.5 m	Higher waste, individual pieces for each step

How Stair Measurements Affect Carpet Quantity

Accurate measurement is the foundation of a correct carpet order. Measure tread depth, riser height and stair width precisely. Small errors multiply across 13 steps, so measure twice and record in metres.

Key Measurements To Take

• Number Of Steps: Count the visible risers (13 in this case).
• Tread Depth (Run): Measure from nosing to back of tread in metres.
• Riser Height: Measure vertical distance from top of one tread to the next in metres.
• Staircase Width: Measure usable carpet width across the stairs in metres.
• Nosing/Overlap Allowance: Measure additional nosing depth if carpet wraps over the front edge of each step.

Two Common Installation Methods And How They Change Material Needs

Carpet can be fitted as a continuous runner from top to bottom or as separate pieces for treads and risers. Each method has a different formula for calculating metres required and waste.

Continuous Runner Method

This method uses a single length from the top landing to the bottom. It is neater and uses less seam work.

Calculation steps: Per-Step Length = Tread Depth + Riser Height. Total Raw Length = Per-Step Length × Number Of Steps. Add allowances for top/bottom overhang, landing returns and waste (typically 10–15%).

Example: Tread 0.28 m + Riser 0.18 m = 0.46 m per step × 13 = 5.98 m raw. With 15% waste, order ≈ 6.9 m.

Separate Treads And Risers Method

Each tread and riser is cut individually and installed, which is useful for patterned carpets, narrow stairs or when a runner is impractical.

Calculation approach: Calculate area for each tread and each riser, then sum and add waste. Treads need extra for front nosing; risers need full height plus seams. This method increases waste and often requires 20–30% more material than a continuous run.

Example Rough Total: If each tread piece requires 0.40 m length and each riser 0.20 m, per step = 0.60 m × 13 = 7.8 m raw. With 15–25% waste, order ≈ 9–9.8 m.

Practical Calculation Examples

Three sample scenarios are provided to illustrate typical U.S. stair dimensions and how many metres to order. All numbers rounded conservatively.

Scenario A — Standard Residential Stair (Continuous Runner)

Measurements: Tread 0.28 m, Riser 0.18 m, Steps 13, Stair Width 1.0 m. Per-step 0.46 m × 13 = 5.98 m raw. Add 15% waste and 0.3 m for top/bottom = 6.9–7.3 m. Recommended order: 7.0–7.5 metres.

Scenario B — Narrow Staircase (Separate Treads & Risers)

Measurements: Tread 0.25 m, Riser 0.175 m, Steps 13, Stair Width 0.85 m. Individual pieces: tread allowance 0.35 m, riser allowance 0.2 m per step = 0.55 m × 13 = 7.15 m raw. With 20% waste = 8.6–9.0 m. Recommended order: 9.0 metres.

Scenario C — Deep Treads Or Added Padding (Continuous Runner)

Measurements: Tread 0.32 m, Riser 0.19 m, Steps 13. Per-step 0.51 m × 13 = 6.63 m. With 15% waste and extras = ≈ 7.8 m. Recommended order: 7.8–8.2 metres.

How Carpet Roll Width Impacts Ordering

Carpet is sold in rolls with fixed widths; the roll width chosen determines how the carpet is cut and whether seams are needed. Always match roll width to staircase width plus trimming allowance.

• Common Roll Widths: 3.66 m (12 ft) is common internationally; some suppliers in the U.S. offer 4.00 m or custom widths. Most domestic stair widths are much narrower than roll width, so width is usually not a limiting factor.
• When Seams Are Required: If a staircase width exceeds the roll width, seams are necessary and increase labor and visible joins.
• Waste Considerations: Wider roll widths can reduce the need for seams but can increase offcuts and waste when cutting multiple pieces for treads and risers.

Allowances: Waste, Pattern Matching, Underlay And Nosing

Order extra carpet to cover cutting waste, pattern matching and underlay. Failing to include these allowances can leave a homeowner short mid-installation.

• Waste Allowance: 10–15% for continuous runners; 15–25% for separate-piece installations or patterned carpets.
• Pattern Repeat: If carpet has a pattern, add material for matching repeats across steps—this can add 10–20% extra.
• Underlay/Padding: Underlay is usually bought separately; for stairs, foam or felt pads sized to stair width and cut per step are typical. Include cost and some extra underlay for mistakes.
• Nosing And Overlap: If carpet wraps over the nosing, add 20–30 mm per step (per tread) to the linear length calculation.

Measuring Checklist And Step-By-Step Guide

A clear workflow prevents errors. Follow these steps to produce measurements suitable for your installer. Provide these exact numbers to the carpet supplier to avoid misorders.

1. Count the number of steps (13).
2. Measure tread depth (front to back) in metres at several steps and use the smallest reliable value.
3. Measure riser height in metres at several steps and use the largest reliable value.
4. Measure staircase width at the middle and near top and bottom; use the narrowest measurement for material width needs.
5. Decide installation method: continuous runner or separate treads/risers.
6. Add allowances: nosing, top/bottom overhang, and waste percent appropriate to the method and pattern.

Ordering From Suppliers: What To Tell The Retailer

When ordering, provide clear, concise metrics. Good communication prevents mistaken cuts and delays.

• Number of steps: 13.
• Per-step measurements in metres: tread and riser.
• Stair width in metres and whether the carpet must wrap the nosing.
• Installation method: continuous runner or individual pieces.
• Carpet roll width preference if known, and whether pattern matching is necessary.
• Request that the supplier include recommended waste allowance in their quote.

Typical Costs And Budget Considerations

Material cost per metre varies by carpet quality and brand. Expect labor to be a significant portion of total cost for stair installations due to complexity. Budget for padding, gripper rods, adhesive and professional fitting if a tight, safe finish is desired.

• Material: Prices vary widely—value grades are less expensive per metre; wool or pattern carpets cost more.
• Labor: Stairs often cost more per square metre to fit than flat floors because of shaping, tacking and trimming.
• Extra Items: Grippers, stair rods (optional), underlay and adhesives add to the bill.

Common Mistakes And How To Avoid Them

Many ordering errors are preventable with careful measurement and clear instructions. Double-check every measurement and state whether dimensions include nosing or not.

• Underestimating waste—always use recommended percentage based on installation style and pattern.
• Not measuring width at narrowest point—causes last-minute seams or returns.
• Forgetting pattern repeats—results in mismatched patterns on steps.
• Assuming all suppliers use the same roll widths—confirm roll width before finalizing order.

Quick Reference Table: Estimated Metres To Order For 13 Stairs

Tread (m)	Riser (m)	Method	Raw Length (m)	With Waste (m)
0.28	0.18	Continuous	5.98	6.9–7.3
0.25	0.175	Separate Pieces	7.15	8.6–9.0
0.32	0.19	Continuous	6.63	7.8–8.2

When To Consult A Professional

Complex stairs—curved, unusually wide, or with landings—benefit from a professional measurement and fit. An experienced installer can advise on seam placement, safety and the most economical layout for your carpet roll.

Final Practical Tips

• Always Order Extra: Err on the side of ordering more metres than exactly calculated to cover mistakes and future repairs.
• Keep Leftover Material: Store a remnant for future patch repairs to match dye lots and wear.
• Confirm Dye Lot: If buying more than one roll, ensure all pieces come from the same dye lot to avoid color variation.
• Ask For A Measurement Check: Many suppliers offer a free or low-cost site measurement—use it if uncertain.