Stair Carpet & Runner Yardage Calculator
Suite subtitle

Stair Carpet & Runner Yardage Calculator

Calculate exact stair carpet linear feet, square yards, and runner rolls for straight or landing flights. Compares Hollywood wrap vs waterfall styles with cut waste.

Load Example:
Parameters & Inputs
Badge inches ft
Sec flight geometry
13

Hint step count

Sec style and pattern

Hint material source

Sec intermediate landing
Lbl continuous length
27.0Unit linear ft
Lbl net: 24.6+10% Lbl buffer
Lbl gross sq yds
8.01Unit sq yds
72 Unit sq ftLbl total purchase
Lbl broadloom cut length
27.0Unit linear ft
1 Lbl strips acrossOpt runner roll short
Lbl padding area
2.64Unit sq yds
Lbl tack strips:65 Unit ft short
Lbl profile viewhollywood
Lbl staple creaseLbl pile directionLbl tread abbr: 10.5"Lbl riser abbr: 7.5"+1.0"

Desc hollywood expl

Lbl roll slit view32 Unit inches Lbl total roll
Lbl roll width: 32 Unit inchesLbl yield: 100.0%
Lbl strip 132.0 "
1 Lbl usable strips0.0% Lbl scrap trim

Desc runner roll expl

Sec breakdown title
Lbl step length unit21.75 Unit inches
Lbl top transition wrap9.0 Unit inches
Lbl bottom anchor3.0 Unit inches
Lbl waste allowance0.73 Unit sq yds
Primary MetricStats card1 sub
Efficiency / CapacityStats card2 sub
Net OutputStats card3 sub

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High-performance calculation executed entirely in browser memory.

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Production Ready Export

Clean, optimized output formats ready for immediate deployment.

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Technical Reference & Architecture Guide

Stair Carpet & Runner Yardage Calculator Guide

Calculate exact stair carpet linear feet, square yards, and runner rolls for straight or landing flights. Compares Hollywood wrap vs waterfall styles with cut waste.

Stair Carpet & Runner Yardage Calculator Guide — Client-Side In-Memory Architecture & Data Flow
Stair Carpet & Runner Yardage Calculator Guide — Client-Side In-Memory Architecture & Data Flow

Key Parameters & Controls

Tread Depth (Unit Run)decimal (inches or cm)

Horizontal distance from the vertical face of one riser to the outer edge of the next. Standard residential building codes (IRC Section R311.7.5.2) mandate a minimum tread run of 10.0 inches (25.4 cm) measured horizontally between vertical planes of adjacent treads.

Default: 10.5 in
Riser Height (Unit Rise)decimal (inches or cm)

Vertical elevation between adjacent tread surfaces. Building code (IRC Section R311.7.5.1) caps maximum residential riser height at 7.75 inches (19.7 cm) with allowable variation across a flight not exceeding 0.375 inches (9.5 mm).

Default: 7.5 in
Nosing Overhang Curvaturedecimal (inches or cm)

Horizontal projection of the tread past the vertical riser below. IRC code stipulates nosings must extend between 0.75 and 1.25 inches (19 to 32 mm) with a maximum radius of curvature of 0.5625 inches (14.3 mm).

Default: 1.0 in
Installation Style Allowancecategorical option

Waterfall cascades the carpet straight from the nosing edge down to the crotch of the tread, requiring only 1.0 inch of contour slack per step. Hollywood (French Cap) wraps the carpet underneath the nosing and staples it flush to the riser, consuming an additional 1.75 to 2.5 inches per tread.

Default: Hollywood / French Cap
Broadloom Roll Width Nestingdimensional width

Standard carpet mills manufacture broadloom in 12-foot (144 in) or 15-foot (180 in) widths. Multiple stair runner strips can be slit across this roll width provided every strip shares the identical pile nap orientation pointing downward.

Default: 12 ft (144 in)
Pattern Repeat Buffer Intervaldecimal (inches or cm)

The vertical interval at which a decorative textile motif repeats. To ensure identical pattern placement on every stair nosing, each tread cut must be rounded up to the nearest integer multiple of the repeat length.

Default: 0.0 in (Solid)

Pro Tips & Best Practices

Universal Pile Direction Law for Staircases

Carpet pile must ALWAYS point downward from the top floor toward the bottom foyer. Installing carpet with the nap pointing upward exposes the backing fibers to reverse friction, causing blinding light reflection, rapid abrasive fiber matting on the nosings, and severe premature delamination.

The 2/3 Tack Strip Gully Spacing Rule

When nailing architectural tack strips to treads and risers, the spacing gap (the gully) between the strip and the adjacent surface must equal exactly two-thirds the compressed thickness of the carpet. A gully that is too wide permits carpet sagging, while an undersized gully prevents the carpet backing from anchoring securely onto the pins.

Padding Termination Boundary

Never wrap carpet padding over the nosing or down the riser. For maximum safety and crisp stair contours, heavy-density bonded urethane pad (8 lb/cu.ft or higher, 0.375-inch thickness) must terminate exactly 1.0 inch short of the tread nosing edge and 1.0 inch inside each stringer edge.

Broadloom Slitting Without Pattern Drift

When cutting three 36-inch stair runner strips from a 12-foot broadloom roll, make all cuts with a cushion-back carpet cutter from the backing side along the manufacturing tuft rows. Never mix cuts across the roll's cross-grain, as cross-grain fibers reflect light at differing refractive angles, creating visible shade banding.

Common Gotchas & Troubleshooting

⚠️Carpet Tenting or Bubbling Under Tread Nosing

Common in Hollywood wraps where manual pressure was insufficient. Use a narrow-crown pneumatic staple gun (1/4-inch crown, 9/16-inch leg) firing between carpet tufts directly against the underside of the bullnose, spaced every 2 inches into solid wood, never into drywall or thin cove molding.

⚠️Shortage at Top Landing Transition

Installers frequently forget that the topmost riser requires full carpet coverage, plus a 6-inch wrap over the top bullnose subfloor to seam cleanly into the upper room's carpet or clamp inside a metal z-bar transition. Always add 12 inches of linear safety length to the total flight calculation.

⚠️Visible Fabric Twisting Across L-Shaped Landings

On 90-degree quarter-turn landings, walking direction rotates, but carpet pile cannot bend. Never turn a runner in a single continuous piece without a 45-degree miter seam or an independent landing block cut aligned with the dominant approach pile.

⚠️Fraying Stringer Margins on Stair Runners

Exposed cut edges on runners will rapidly fray without post-cut finishing. If slitting a broadloom roll down to runner dimensions, send the strips to a local rug fabrication workshop for serging (whip-stitching) or wide-cotton canvas binding before installation.

Frequently Asked Questions

How do you calculate how much carpet you need for stairs?▼

Add the tread depth plus the riser height plus 1 inch for waterfall style (or 2 inches for Hollywood wrap), multiply by the total number of risers, add 12 inches for top/bottom floor anchoring wraps, and add your landing square footage. Convert total linear inches to feet by dividing by 12, then multiply by stair width (in feet) and divide by 9 to obtain required square yards.

What is the difference between waterfall and Hollywood stair carpet installation?▼

Waterfall installation allows the carpet to drop straight down from the nosing to the crotch of the step below in a clean, gentle slope without tacking beneath the overhang. Hollywood installation (French cap) wraps the carpet tightly around the nosing radius and staples it horizontally to the underside of the tread overhang and against the riser face, consuming an extra 1.5 to 2.5 inches of carpet per step.

How many square yards of carpet is an average 13-step staircase?▼

A standard residential 13-riser straight staircase with 10.5-inch treads, 7.5-inch risers, and a 36-inch width consumes approximately 22.5 to 25.0 linear feet of carpet. This equates to roughly 7.5 to 8.5 square yards of carpet for a 36-inch wide flight, or approximately 15 square yards if purchasing a minimum 12-foot broadloom cut without slitting.

Do you need padding under stair carpet runners?▼

Yes. A dense, high-performance carpet pad (minimum 8-pound density and maximum 3/8-inch or 7/16-inch thickness) is mandatory on stairs. It absorbs severe downward impact, prevents early fiber breakdown on tread nosings, and keeps the carpet from shifting under foot. Padding is installed only on the tread surface, ending 1 inch short of the nosing.

How do you calculate pattern repeat waste on stair carpet?▼

Measure the carpet's vertical pattern repeat in inches. If one step requires 19.5 inches of carpet (Hollywood style) and the pattern repeat is 6 inches, round up 19.5 to the next multiple of 6 (which is 24 inches). That 4.5-inch difference per tread constitutes pattern-matching waste, accumulating 63 inches (5.25 feet) of required extra carpet over 14 steps.

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