Carpet Stair Runner Calculator

Calculate the exact linear footage, linear meters, and yardage of carpet runner needed for your staircase — including riser height, tread depth, bullnose wrap, and waste overage.

Carpet Stair Runner Calculator

Calculate the exact yardage and linear footage required to install a continuous carpet runner on your staircase — including bullnose wrap and waste overage.

Cross-section: 1 Stair = Riser + Tread + Bullnose Wrap

┌──── Tread (10.0") ────┐

│ │ ← Bullnose wrap

Riser │ ╰── (1.5")

(7.5") │

└─────────────────────────────

Per stair: 7.5 + 10.0 + 1.5 = 19.0 inches

01 — Stair Dimensions

Number of Stairs

Riser Height (inches)

Typical US code: 6.5"–8" max rise

Tread Depth (inches)

Typical US code: 10" min run

Bullnose / Nosing Wrap (inches)

Typical: 1–2" per stair depending on nosing profile

Waste / Pattern Overage (%)

Per Stair Length

19.00 inches

1.58 ft

Exact Total Length

22.17 ft

266.00 inches

Order This Much

24.38 ft

8.13 yards

02 — Full Calculation

Number of stairs	14
Riser height	7.50 inches
Tread depth	10.00 inches
Bullnose wrap	1.50 inches
Per stair (R + T + B)	7.50 + 10.00 + 1.50 = 19.00 inches
Exact total (per stair × 14)	19.00 × 14 = 266.00 inches = 22.17 linear feet
Waste factor (10%)	× 1.100
Total to order	24.38 linear feet (8.13 yards)

Summary: To cover 14 stairs (7.5" riser + 10.0" tread + 1.5" bullnose) with a 10% waste buffer, you need to order 24.38 linear feet (8.13 yards) of carpet runner.

Practical Example

A homeowner has 14 stairs with a 7.5-inch riser, 10-inch tread, and 1.5-inch bullnose wrap. Per stair: 7.5 + 10 + 1.5 = 19 inches. Exact total: 19 × 14 = 266 inches = 22.2 linear feet. With 10% waste: 22.2 × 1.10 = 24.4 linear feet to order. Carpet runners are sold by the linear foot or linear yard (1 yard = 3 feet). 24.4 ft ÷ 3 = 8.1 yards — order 9 yards to the nearest full yard. Typical runner widths: 26", 27", or 32" — measure your tread width and leave a 1–2" wood border on each side for the classic look.

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What is Carpet Runner Installation: Measuring, Ordering, and Installing Stair Runners?

Calculate the exact yardage and linear footage required for your stair runner installation — and understand the trade-offs between waterfall vs. Hollywood installation methods.

Mathematical Foundation

Runner Length Formula

L_{total} = N_{stairs} \times (Riser + Tread + Bullnose)

N_{stairs}

= Number of stairs. Count each step from bottom to top. The landing (if present) is typically NOT covered by a stair runner — measure it separately as a hallway runner.

Riser

= The vertical face of each step (height). IBC residential code: maximum 8-3/4 inches (222mm) riser height.

Tread

= The horizontal walking surface. IBC minimum: 10 inches (254mm) run (nosing-to-nosing measurement).

Bullnose

= The amount of carpet that wraps over and under the nosing (leading edge) of each tread. Typical: 1–2 inches per stair for a clean wrap.

With Waste Overage

L_{order} = L_{total} \times (1 + W)

W

= Waste fraction (e.g., 0.10 for 10%). Accounts for pattern repeat alignment, installation errors, and cut offs. Use 15–20% for patterned carpet, 10% for solid colors.

Laws & Principles

Waterfall vs. Hollywood installation: Waterfall installation wraps the carpet over the nose of each step vertically — it's the faster method and is more forgiving. Hollywood installation tacks the carpet flat to each tread and riser separately, following the contour exactly — more material required per stair (add 3–4 extra inches per stair for the undercut). This calculator uses the simpler waterfall method.
Pattern repeat: if your runner has a repeating pattern, you must add one full pattern repeat (typically 13–27 inches for geometric patterns) to your order quantity to allow matching at each stair. Use 15–20% waste for patterned carpets instead of 10%.
Width selection: standard stair runner widths are 26 inches, 27 inches, and 32 inches. Measure the actual stair width and subtract 3–6 inches on each side to expose wood border. Most staircases (36-inch-wide stairs) use 27-inch runners with a 4.5-inch border on each side.
Padding: stair carpet pads extend the life of your runner dramatically. Use double-sided tape on each tread to hold the pad, then install the runner over the pad. Do NOT install pad on risers — it causes visible bulging. Pad goes on treads only, cut flush to the back edge.
Carpet over carpet: never install a stair runner directly over existing broadloom carpet. Remove old carpet to the bare subfloor first. Runners installed over old carpet compress unevenly and become a serious trip hazard as the underlying carpet wears unevenly.

Step-by-Step Example Walkthrough

" Contractor measuring a 14-step colonial staircase for a patterned wool stair runner. "

Measure: riser = 7.5 inches, tread = 10 inches, bullnose wrap = 1.5 inches.
Per stair: 7.5 + 10 + 1.5 = 19 inches.
Total exact: 19 × 14 stairs = 266 inches = 22.2 linear feet.
Pattern repeat: the chosen wool runner has a 18-inch medallion pattern repeat.
Add pattern repeat to waste: use 20% → 22.2 × 1.20 = 26.6 linear feet.
Convert to yards: 26.6 ft ÷ 3 = 8.9 yards → order 9 yards.

Final Result: Order 9 yards of 27-inch wide wool runner. This allows full pattern alignment at each stair with a 20% buffer for cuts and adjustments. At $45/yard installed, total cost ≈ $405 for materials.

Quick Answer: How much carpet runner do I need for stairs?

Measure each stair's riser height + tread depth + bullnose wrap, multiply by the number of stairs, then add 10–20% for waste. A typical 13-step staircase with 7.5" risers and 10" treads needs about 21 linear feet (7 yards) of runner with 10% waste. Use 15–20% waste for patterned carpet to allow for pattern matching at each step.

The Core Formula

Runner Length = Stairs × (Riser + Tread + Bullnose) × (1 + Waste%)

The bullnose wrap (typically 1–2 inches) accounts for carpet wrapping over the lip of each step. Without this term, your runner will be too short and won't tuck properly at the nosing. Always round up to the next full yard when ordering — carpet is sold by the yard, not by the foot.

Quick Yardage Reference

Stairs	Linear Feet (10% waste)	Yards to Order	Cost Estimate ($30–$60/yd)
10	17.4 ft	6 yd	$180–$360
13	22.7 ft	8 yd	$240–$480
14	24.3 ft	9 yd	$270–$540
16	27.7 ft	10 yd	$300–$600
20	34.7 ft	12 yd	$360–$720

Based on standard dimensions: 7.5" riser, 10" tread, 1.5" bullnose wrap, 10% waste. Patterned carpet requires 15–20% waste — add 1–2 extra yards.

Installation Scenarios

Waterfall Installation

The carpet drapes over the nosing and hangs straight down to the next tread — like a waterfall. This is the easier DIY method and uses slightly less material. Best for solid-color or low-pile runners. The exposed gap at the bottom of each riser is a signature aesthetic of this style.

Hollywood (Cap-and-Band) Installation

The carpet is tucked into the crease between tread and riser on both sides, following every contour snugly. This method requires 3–4 extra inches per stair for the undercuts and is best done by a professional installer. It produces a more tailored, upscale look and is the standard for high-end wool and silk runners.

Pro Tips

Do This

✓Measure every stair individually. Stairs are rarely perfectly uniform — especially in older homes. Riser heights can vary by 1/4–1/2 inch from top to bottom. Measure the tallest and shortest and use the average, then add extra waste to compensate.
✓Install stair pad on treads only. Cut pad pieces to fit each tread from nosing to the back edge. Attach with double-sided carpet tape. Never put padding on risers — it creates unsightly bulges and makes the runner lift off the vertical surface.
✓Order an extra yard for future repairs. Stair runners wear fastest at the nosing (front edge) of each tread. Having matching material on hand lets you shift the runner down one stair to redistribute wear, or patch a damaged section without a visible color mismatch from dye lot differences.

Avoid This

✗Don't install runners over existing carpet. Old carpet underneath creates uneven compression that becomes a trip hazard. Always strip to bare wood or subfloor first. The old carpet fibers also trap moisture and odors that transfer to your new runner.
✗Don't use a runner that's too wide. The exposed wood border on each side isn't just decorative — it lets you see the edge of each tread for safe foot placement. Most designers recommend 3–6 inches of exposed wood on each side. A runner that's too wide hides the tread edge and increases fall risk.
✗Don't skip the tack strips. Stair runner tape alone won't hold under foot traffic. Professional installations use angled tack strips at the crease of each tread-riser junction. Without them, the runner will shift, bunch, and become a serious slip hazard within months.

Frequently Asked Questions

What width stair runner should I buy?

Standard runner widths are 26", 27", and 32". For a typical 36"-wide staircase, a 27-inch runner leaves a 4.5-inch exposed wood border on each side — the most common and aesthetically balanced proportion. For wider staircases (42"+), use a 32-inch runner. Always measure your actual stair width and subtract 6–10 inches total for the combined border.

How much extra should I order for patterned carpet?

For patterned runners (stripes, geometrics, medallions), add 15–20% waste instead of the standard 10%. Patterns must align at every single step — misaligned patterns are immediately visible and look unprofessional. Ask your carpet supplier for the exact pattern repeat measurement (typically 13–27 inches for geometric designs) so you can calculate precisely how much extra you need.

Can I install a stair runner myself (DIY)?

Yes — waterfall installation is a manageable DIY project. You'll need a staple gun, tack strips, a knee kicker (rental), carpet pad, and a utility knife. Budget 3–5 hours for a 13-step staircase. Hollywood installation is significantly harder and typically requires a professional — the tucking and stretching at each tread-riser junction demands experience and specialty tools to avoid visible wrinkles.

How long does a stair runner last?

A quality wool runner lasts 10–15 years with normal residential traffic. Synthetic (nylon/polyester) runners last 5–8 years. The nosing edge of each tread wears fastest. Extending life: use quality stair pads, vacuum weekly, and consider shifting the runner down one stair every 2–3 years to redistribute wear across different sections of the carpet.

Carpet Stair Runner Calculator