Carpet Calculator
How much carpet do you actually need? This free carpet calculator gives DIYers and flooring contractors a complete materials list — broadloom square yards with roll-width seam plan, carpet pad rolls (6' × 45' = 270 sq ft), tackless gripper strip in 4 ft pieces, hot-melt seam tape, seam sealer, Z-bar and binder-bar transitions, and an optional waterfall or Hollywood stair runner.
Every other free carpet calculator online stops at "area × 1.1 ÷ 9 = square yards." That ignores the part installers actually plan around: carpet does not bend. If your room is wider than the roll, you need a fill piece seamed in — and the seam adds material AND a labor step AND a CRI 105 placement constraint. Berber and patterned goods change the math again with pad-class restrictions and pattern-repeat allowances.
Built on the Carpet & Rug Institute installation standards (CRI 104 commercial, CRI 105 residential), HUD/FHA UM 72a cushion classes via the Carpet Cushion Council, ASTM D5252/D5417 durability tests, ASTM F1869/F2170 subfloor moisture limits for glue-down, and CRI Green Label Plus VOC certification. Materials only — no pricing, no labor, no signup.
See 2026 carpet installation cost ranges →
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Carpet Calculator
Estimate broadloom carpet (with seam plan), pad, tackless strip, seaming tape, transitions, and stair runner — per CRI 104/105 and HUD UM 72a.
Rooms
Doorways subtract from tackless-strip LF. The carpet→carpet count drives Z-bar transitions vs binder bars.
Wondering where the seam ends up? See the seam-placement & pile-direction diagram
Carpet selection
Set repeat to 0 for solid or random-texture carpet. Patterned goods add one repeat of length per seam (per CRI 105 / FlooringInc pattern-match guide).
Why does roll width matter so much? See how the 12-ft roll drives strips & seams
Pad / cushion
Berber and commercial loop carpets require Class 2 cushion ≤3/8". Using a thicker / softer pad voids most wear warranties — the calculator will warn you.
Installation method
Triggers ASTM F1869 / F2170 moisture-test note when paired with glue-down.
What do the tackless strip and pad rolls do? See the stretch-in cross-section
Stairs (optional)
How carpet actually gets cut and laid
Carpet is the one floor where square footage alone misleads you. These engineering-style diagrams cover the three things that decide how much you really buy and whether the job looks right: why the 12-ft roll width forces a fill strip and a seam, where to place that seam (and which way the pile faces), and how a stretch-in carpet is anchored with tackless strip and pad.
The roll-width diagram is why the calculator can ask for more carpet than the room’s bare square footage. Broadloom comes off a fixed-width roll, so any room wider than the roll needs a second strip and a seam, and the fill strip adds material. Running the strips along the longer wall keeps the seam short — the layout, not just the area, sets how much you buy.
The seam-placement comparison explains why two rooms of the same size can need different amounts of carpet. Seams run parallel to the main light and out of traffic, and every strip’s pile has to face the same way, so a reversed strip looks like a different color. Those layout rules can force an extra strip, which is why the estimate is not just area divided by roll width.
The stretch-in section is why the take-off carries tackless strip and pad as their own lines. A residential carpet is anchored, not glued: tackless strip grips the stretched carpet at the walls, the pad butts to it, and the edge tucks into the gully. That is what the tackless linear-foot and pad-roll outputs cover, separate from the carpet field.
Calculation Formulas
Sum every rectangular room. For L-shaped rooms, split into rectangles. Doorways and openings under ~1 sq ft are not deducted from carpet — only from tackless-strip linear feet.
Example:
16 ft × 12 ft bedroom = 192 sq ft.
Strips run along the room's longer dimension to minimize seams. Cross_dim is the shorter side. Carpet does not bend — if cross_dim exceeds roll width, you need a fill piece (seamed in).
Example:
12 ft roll in a 16'×12' room: cross = 12 ft → 1 strip, no seam. Same roll in a 16'×14' room: cross = 14 ft → 2 strips, 1 seam 16 ft long.
Each strip is the full roll width × (room length + trim allowance). Default cutting allowance is 4 in per strip for tuck and trim.
Example:
16 ft long room → each strip is ~16.33 ft running.
Patterned broadloom must align at every seam — add one full pattern repeat of length per cut after the first. Solid carpet has repeat = 0.
Example:
18-inch pattern × 2 seams = 3 ft of pattern allowance added to running length.
This is the geometric requirement — what the roll physically delivers. It is the number suppliers quote, NOT the room's bare square footage. Customers under-order when they ask for bare area only.
Example:
1 strip × 16.33 ft × 12 ft roll = 196 sq ft (vs 192 sq ft bare area).
Construction-specific waste covers cuts, dye-lot reserves, and installation errors on top of the roll-width geometry. Cut pile solid 10%, frieze 10%, Berber/loop 15%, patterned 15%, complex/irregular 20%+ (per CRI 105 commentary and installer practice).
Example:
196 sq ft × 1.10 (cut pile solid) = 215.6 sq ft ÷ 9 = 23.96 sq yd to order.
Standard pad is a 6 ft × 45 ft roll = 270 sq ft. Pad seams are invisible under the carpet, so pad pieces freely — no roll-width geometry penalty. Add ~5% for trim. Glue-down installations use no pad.
Example:
Three rooms totaling 540 sq ft net = ⌈ 567 ÷ 270 ⌉ = 3 rolls.
Tackless strip runs the room perimeter MINUS each doorway opening (doorways get transitions instead). Strip is sold in ~4 ft pieces. The 'perimeter ÷ 4' shortcut some calculators use is wrong — it ignores doorways.
Example:
16'×12' room perimeter = 56 LF − one 36" doorway (3 ft) = 53 LF ÷ 4 ft pieces = 14 pieces.
Hot-melt 3-inch seaming tape, +10% overlap for splices. Default roll length is 66 ft (Premier / Roberts / Bond Products); confirm per SKU as some brands ship longer rolls.
Example:
60 LF of seams × 1.10 = 66 LF ÷ 66 ft per roll = 1 roll.
Per-step run length = tread depth + riser height + a method-specific nose allowance. Waterfall drapes over the nose (~2 in extra); Hollywood wraps the nose tightly and tucks (~5 in extra). Total runner LF = steps × LF/step + landings, then +10% per CRI / runrug practice.
Example:
13 steps × (10 in tread + 7.5 in riser + 3 in waterfall nose) ÷ 12 = 22.3 LF raw × 1.10 = 24.6 LF runner.
Standard Constants
| Constant | Value | Description |
|---|---|---|
| Standard Roll Width | 12 ft (US residential) | 12 ft is the dominant North-American residential and most commercial standard. 15 ft wide-goods eliminates seams in 12-15 ft rooms. 13'2" (~4 m) is the European / wool standard. 6 ft rolls are utility / commercial / hallway only. |
| Pad Roll Coverage | 270 sq ft (6' × 45') | Standard carpet pad roll dimensions across all density classes. Wide rolls (12 ft, 15 ft) exist for large open spaces but are special-order in most markets. |
| Pad Density (residential) | 8 lb / ft³ default | HUD UM 72a Class 1 minimum is 5.0 lb/ft³ rebond, but 8 lb at 7/16" is the industry residential default. 6 lb is budget, 10 lb is high-traffic / stairs. Class 2 minimum is 6.5 lb/ft³. |
| Pad Thickness Limits | ≤ 1/2" residential · ≤ 3/8" Berber / stairs | Carpet Cushion Council caps residential cushion at 0.5" total thickness. Berber, commercial loop, and stair applications use ≤3/8" denser (Class 2) pad to prevent loop flex and seam separation — common installer convention, not a HUD-published rule. |
| Tackless Strip Length | ~4 ft pieces | Standard gripper-strip piece length in North America (1-2 m range; ~4 ft is the common SKU). Pins angle toward the wall. Different fastener types for wood vs concrete subfloors. |
| Tackless Gully | ≤ 3/8" wall gap | Per CRI 105: the gully (gap between tackless strip and wall) should be slightly less than carpet thickness and may not exceed 3/8". |
| Long-Run Threshold | 30 ft | Per CRI 105: stretched runs longer than 30 ft require architectural-grade tackless strip (1-3/4" wide, 3 rows of pins) or two parallel conventional strips. Single strip will not hold the power-stretcher tension. |
| Seam Tape | 3" hot-melt, 66 ft roll (typical) | 3-inch wide, fiberglass-reinforced hot-melt tape activated by a seaming iron over a seaming board. Roll length varies by brand — 66 ft is common (Premier 330 series, Roberts 50-560), some products ship longer. |
| Waste Factor Floor | 10% standard residential | Industry default for simple rectangular rooms with solid cut pile. Frieze runs the same. Berber, loop, and patterned carpets need 15%+. Complex (multi-room with closets, L-shapes, stairs) runs 20%+. |
| ASTM F1869 Threshold | ≤ 3 lb / 1000 sq ft / 24 hr | Maximum acceptable moisture vapor emission rate (MVER) via calcium chloride test before glue-down carpet on concrete. Industry standard adopted by CRI 105. Skipping this test is the #1 failure mode for glue-down. |
| ASTM F2170 Threshold | ≤ 75% RH | Maximum relative humidity reading via in-situ probes in the concrete slab. Requires 3 probes for the first 1,000 sq ft + 1 per additional 1,000 sq ft, slab conditioned ≥48 hr before reading. |
| IRC Stair Dimensions | Riser ≤ 7-3/4" · Tread ≥ 10" | IRC R311.7 sets max riser height at 7-3/4 inches and minimum tread depth at 10 inches for residential stairs. Calculator defaults use 10" tread and 7.5" riser — within the IRC envelope and matches the most common framed stair. |
Note: All calculations include appropriate waste factors based on project complexity and material type. Results are estimates and should be verified by professionals before purchasing materials.
CRI 105 — Standard for Installation of Residential Carpet(CRI 105 (2015))
View StandardThe Carpet & Rug Institute's industry-authored installation standard for residential carpet. Free to download. Functions as an umbrella standard that repeatedly defers to the carpet manufacturer's product-specific instructions, but does prescribe acclimation, tackless gully, seam orientation, power-stretcher use, and long-run requirements.
Key Requirements:
- •Acclimate carpet, pad, and adhesive 24-48 hours at service temperature and humidity before installation
- •Tackless strip gully (gap to wall) ≤ 3/8" and slightly less than carpet thickness
- •Stretched runs > 30 ft require architectural strip (1-3/4", 3 rows of pins) or two parallel strips
- •Power stretcher required for compliant residential stretch-in — knee-kicker alone is not compliant
- •Seam orientation: keep seams out of pivot points and main traffic paths; orient away from primary light source
- •Subfloor moisture testing per ASTM F1869 and/or F2170 before any glue-down or double-glue installation
CRI 104 — Standard for Installation of Commercial Carpet(CRI 104 (2015))
View StandardCompanion standard to CRI 105 covering commercial installation (glue-down, double-glue, carpet tile). Prescribes the same subfloor moisture testing thresholds plus heavier-traffic acceptance criteria for appearance retention.
Key Requirements:
- •Direct glue-down and double-glue are the commercial defaults; stretch-in only in light-commercial applications
- •Adhesive selection per CRI Green Label Plus + manufacturer compatibility
- •Subfloor flatness: 3/16" in 10 ft for direct glue, 1/8" in 10 ft for carpet tile
- •Subfloor moisture: ASTM F1869 ≤ 3 lb MVER and/or ASTM F2170 ≤ 75% RH before adhesive application
- •Appearance Retention Rating (ART) ≥ 3.5 typical for commercial broadloom (per CRI TM-101)
HUD/FHA UM 72a — Carpet Cushion (via Carpet Cushion Council)(HUD UM 72a)
View StandardFederal cushion standard administered by the Carpet Cushion Council. Splits cushion into Class 1 (light/moderate residential) and Class 2 (heavy/multifamily public areas; recommended for stairs and halls). Establishes minimum density and thickness by cushion type — rebond, prime urethane, fiber, and rubber.
Key Requirements:
- •Bonded urethane (rebond) — Class 1: ≥ 5.0 lb/ft³, Class 2: ≥ 6.5 lb/ft³, minimum 3/8" thickness
- •Flat rubber — Class 1: 18 lb/ft³ at 0.22", Class 2: 21 lb/ft³ at 0.22"
- •Synthetic fiber / felt — density and weight specs per material subtype
- •Maximum cushion thickness 1/2" (CCC residential guidance, all products)
- •Berber, commercial loop, and stair applications: ≤ 3/8" thickness, denser pad (Class 2)
ASTM D5252 / D5417 — Carpet Durability (Hexapod & Vettermann)(ASTM D5252-24 / D5417)
View StandardLaboratory durability tests for carpet appearance retention. ASTM D5252 (Hexapod) and D5417 (Vettermann) tumble a steel ball studded with cleats over a sample to simulate foot-traffic wear. Results are graded for appearance retention via CRI TM101 (1-5 scale). Commercial broadloom specs frequently require ART ≥ 3.5.
Key Requirements:
- •Hexapod (D5252): drum + steel ball with 6 polyurethane cleats, run cycles per traffic class
- •Vettermann (D5417): 28.75" drum + ~16 lb studded ball, alternative durability protocol
- •Appearance retention scored per CRI TM-101 (1 = severe change, 5 = no visible change)
- •Commercial light-traffic: ART ≥ 2.5; moderate: ≥ 3.0; heavy / executive: ≥ 3.5
- •Tests are run on the carpet alone — pad is not part of the rated assembly
ASTM F1869 / F2170 — Concrete Subfloor Moisture(ASTM F1869-23 / F2170-23)
View StandardThe two industry-standard tests for measuring concrete subfloor moisture before installing glue-down flooring. F1869 uses calcium chloride to measure moisture vapor emission rate (MVER); F2170 uses in-situ relative humidity probes embedded in the slab. CRI 105 requires one or both before any glue-down or double-glue carpet on concrete.
Key Requirements:
- •F1869: ≤ 3 lb / 1000 sq ft / 24 hr MVER (industry-standard acceptance)
- •F2170: ≤ 75% RH; 3 probes for the first 1,000 sq ft + 1 per additional 1,000 sq ft
- •F2170: slab and ambient conditioned ≥ 48 hr at service conditions before reading
- •Place one probe within 3 ft of each exterior wall
- •F710 — concrete prep practice (cleanliness, alkalinity, surface profile) is a prerequisite to either moisture test
CRI Green Label Plus — VOC Emissions(CRI GLP)
View StandardVoluntary CRI third-party VOC-emissions certification for carpet, adhesive, and cushion. 14-day environmental-chamber test per California CDPH Section 01350 across 13 chemicals (carpet) and 12 chemicals (adhesive), with annual re-testing required to maintain the label. Used toward LEED v4 IEQ Credit, Green Globes, and Green Guide for Health Care.
Key Requirements:
- •Initial 14-day chamber test per CDPH Section 01350 protocol
- •13 chemicals tested for carpet (formaldehyde, 4-PC, styrene, etc.)
- •12 chemicals tested for adhesive
- •Annual third-party retesting to maintain certification
- •Visible logo on carpet labels and adhesive packaging when certified
IRC R311.7 — Stairways (for stair-carpet defaults)(IRC R311.7 (2021))
View StandardInternational Residential Code requirements for stair dimensions, used by the calculator as the default tread / riser geometry for stair runner math. Carpet itself is not regulated by IRC, but every stair the calculator estimates uses these envelope dimensions.
Key Requirements:
- •Maximum riser height: 7-3/4 inches
- •Minimum tread depth: 10 inches
- •Nosing: 3/4" to 1-1/4" projection where tread depth is < 11 inches
- •Maximum variation between adjacent risers or treads: 3/8 inch
- •Minimum stair width: 36 inches above handrail
Standards Disclaimer: Standards and codes are subject to periodic updates. Always verify current requirements with local building authorities and professional engineers before beginning construction. Links provided are for reference only.
Climate, Subfloor, and Pad Selection
Humid climates and concrete subfloors drive cushion and install-method choice
Standard 8 lb rebond pad over wood subfloor is the national residential default. Concrete slabs, below-grade basements, and humid coastal climates demand a denser closed-cell or rubber cushion to manage moisture and prevent mildew under the carpet.
Regional Examples:
Berber, Loop, and Commercial — Pad Class 2 Required
The most common warranty-voiding mistake in carpet installation
Loop-pile carpets (Berber, level loop, commercial broadloom) require a Class 2 cushion — denser, ≤ 3/8" thick — to prevent loop flex and seam separation. Installing Berber over standard 8 lb residential pad voids most manufacturer warranties and produces visible wrinkling within months.
Regional Examples:
Stair Method by House Style and Carpet Type
Waterfall is universal default; Hollywood is for low-pile and formal stairs
Waterfall installation (carpet drapes over the nose, not fastened to riser face) is faster, uses less material, and tolerates thick or patterned goods. Hollywood (cap-and-band, tucked tight to nose) is more material and labor but produces a tailored look — best with low-medium pile in formal stair halls.
Regional Examples:
Pre-1978 Homes and Lead-Safe Carpet Replacement
EPA RRP rule applies when disturbing old painted trim or subfloor
Carpet replacement in pre-1978 homes can disturb lead-painted baseboards, tackless strip nail holes in plaster, and historic subfloor finishes. The EPA Renovation, Repair, and Painting rule applies when disturbed painted area exceeds 6 sq ft interior. Calculator does not estimate disposal labor — but flag the rule before scoping demo.
Regional Examples:
Fiber Selection by Room and Household
Nylon, triexta, polyester, olefin, wool — each fits different rooms
Fiber choice drives durability, stain resistance, and cleanability — not waste or pad spec. Nylon and triexta are the workhorse synthetics; polyester is the soft / budget option; olefin handles basements; wool is the premium specification.
Regional Examples:
Dye-Lot Matching and Attic Stock
The repair-and-warranty rule every homeowner misses
Carpet dye lots vary measurably across production runs. All carpet for one contiguous area must come from a single dye lot — different lots show as visible color bands at seams under raking light. Plan attic stock (extra material kept for repairs) at order time, not after damage.
Regional Examples:
Before You Build
- •Contact your local building department for specific requirements
- •Verify frost line depths, wind zones, and seismic requirements for your area
- •Check if permits are required and schedule required inspections
- •Consult with a local contractor familiar with local codes
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Want to Learn More?
How much carpet to buy — roll-width math and fill-piece seams, waste by carpet type, pad rolls, tackless and seam tape, plus stair runner math.
Read the How Much Carpet Do I Need? Roll Width & Waste Guide
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How to Use This Calculator
- Add every room you're carpeting: enter length and width in feet. Add doorways (count and width in inches) for tackless and transition math.
- Pick carpet construction: cut pile (plush, Saxony, frieze), loop (level loop, Berber), cut-and-loop / patterned, or commercial broadloom. Construction drives base waste % (10% solid cut pile, 15% Berber and patterned) and pad-class compatibility.
- Pick fiber: nylon for high traffic, triexta for pets and basements, polyester for soft / budget, olefin for moisture-prone areas, wool for premium.
- Pick broadloom roll width: 12 ft is the US residential standard, 15 ft eliminates seams in 12–15 ft rooms, 13'2" is the European / wool standard, 6 ft is utility / commercial.
- Enter pattern repeat in inches if the carpet is patterned (0 for solid). Each seam after the first needs one repeat of length added.
- Pick pad: 8 lb / 7/16" rebond is the residential default. Berber and commercial loop need Class 2 (10 lb rebond ≤ 3/8" or synthetic fiber). The calculator warns when carpet and pad are mismatched.
- Pick install method: stretch-in over pad (residential standard), direct glue-down (commercial), or double-glue. Check "concrete subfloor" to surface the ASTM F1869 / F2170 moisture-test note for glue-down installs.
- Optional — add stairs: enter step count, tread depth, riser height, runner width, and pick waterfall (drapes over the nose) or Hollywood (wraps tight). Defaults match IRC R311.7 stair dimensions.
- Click Calculate: see square feet and square yards to order with the waste factor included, per-room broadloom layout with seam plan, pad rolls, tackless pieces, seam tape rolls, transitions, and an installation-notes block with dye-lot and acclimation guidance.
Why Roll-Width Geometry Matters More Than Waste Percentage
Carpet is sold by the linear foot of full roll width — not by net square footage. A 12 ft × 14 ft bedroom on 12 ft broadloom is seamless: one strip 14 ft long × 12 ft wide = 168 sq ft. But a 14 ft × 12 ft bedroom (same room, rotated) becomes 14 ft wide × 12 ft long — and 14 ft exceeds the 12 ft roll. Now you need two strips (12 ft + 2 ft fill piece), one seam 12 ft long, and roughly 192 sq ft of face material instead of 168. Same room, +14% material, plus a seam. The calculator orients strips along the longer side automatically to minimize seams, then applies the construction-specific waste % on top of the roll-width geometry. That is the materials list your supplier will quote against — not the bare floor area. CRI 105 §10 ("Seams") and §11 ("Stretch-in Installation") govern seam placement and the long-run rule: stretched walls over 30 ft require architectural-grade tackless or two parallel strips, because a single strip will not hold a power-stretcher tension over that distance.
Frequently Asked Questions
How much carpet do I need for a 12×14 bedroom?
12 ft × 14 ft = 168 sq ft net floor area. On 12 ft broadloom, run the carpet length along the 14 ft side — one strip, no seam, 14 ft running × 12 ft roll width = 168 sq ft of face material. Add 10% waste for cuts and dye-lot reserves: 184.8 sq ft ÷ 9 = 20.5 square yards to order. If the room were 14 ft × 12 ft instead (same room, rotated relative to the roll), the 14 ft dimension would cross the roll width — now you need two strips with a 12 ft seam and roughly 192 sq ft of face. Same room, +14% material. This is why every carpet calc that ignores roll width under-orders.
What's the standard carpet waste factor?
Per CRI 105 commentary and installer practice: 10% for solid cut pile (plush, Saxony, frieze) in simple rectangular rooms — this is the near-universal residential default. 15% for loop pile (level loop, Berber, commercial) and for any patterned carpet because seams must align. 20%+ for complex rooms (L-shapes, multi-closet, irregular). For patterned broadloom, ADD a pattern-repeat allowance on top: one full repeat of length per cut after the first. A 24-inch pattern × 3 seams = 6 extra feet of running length.
What size carpet pad do I need?
Per HUD UM 72a (Carpet Cushion Council): bonded rebond urethane at 8 lb/ft³ density and 7/16" thickness is the residential standard for cut-pile carpet (Class 1 cushion). 6 lb is budget; 10 lb is high traffic. Berber, level loop, and commercial broadloom require Class 2 cushion — denser AND thinner: 10 lb rebond ≤3/8" or synthetic fiber pad. Pad thicker than 3/8" under Berber causes loop flex and seam separation, voiding most manufacturer warranties. Pad rolls are 6 ft × 45 ft = 270 sq ft. Round up: net floor area × 1.05 ÷ 270 = pad rolls needed.
How many feet of tackless strip do I need?
Tackless strip linear feet = room perimeter minus doorway widths. A 12 × 14 ft room with one 36-inch doorway: perimeter is 2 × (12 + 14) = 52 LF, minus 3 ft for the doorway = 49 LF. Strip is sold in approximately 4 ft pieces: 49 ÷ 4 = 13 pieces. Per CRI 105, the gully (gap between strip and wall) must be slightly less than carpet thickness and never exceeds 3/8". For stretched runs over 30 ft, CRI 105 requires architectural-grade strip (1-3/4" wide, 3 rows of pins) or two parallel conventional strips — single strip will not hold the power-stretcher tension.
Waterfall vs Hollywood stair carpet — what's the difference?
Waterfall installation drapes the carpet over the tread nose and straight down to the next tread (not fastened to the riser face). It's faster, uses less material, tolerates thick or patterned goods, and is the most common residential method. Hollywood (cap-and-band, upholstered) wraps the carpet tightly around each nose and tucks/staples it to both tread and riser — more material and labor but produces a tailored look with a crisp nose. Best with low-to-medium pile in formal stair halls. Per-step run: waterfall ≈ (tread + riser + 2") ÷ 12; Hollywood adds about 3 more inches per step for the wrap. Add 10% per CRI / runrug practice.
Do I need a moisture test before glue-down carpet?
Yes — CRI 105 requires it on any concrete subfloor for glue-down or double-glue installation, and skipping it is the #1 failure mode for glue-down carpet. Two acceptable tests: ASTM F1869 calcium chloride MVER must read ≤ 3 lb per 1000 sq ft per 24 hr, or ASTM F2170 in-situ relative humidity probes must read ≤ 75% RH. F2170 needs 3 probes for the first 1,000 sq ft + 1 per additional 1,000 sq ft, with the slab conditioned at service temperature and humidity ≥ 48 hr before reading. The full procedure is documented in ASTM F2170-23. Failed tests mean either a vapor barrier or a delay until the slab dries — not a glue-down install.
How is carpet priced — by square foot or square yard?
Carpet has historically been priced per square YARD in the US, though many retailers (Lowe's, Home Depot, Empire Today) now quote per square FOOT to match how flooring is sold. The unit your supplier quotes is the LINEAR FOOT OF FULL ROLL WIDTH — they cut from a 12 ft or 15 ft roll and bill the running length × the roll width. The calculator reports both: square feet to order (the literal supplier line item) and square yards (legacy convention; divide sq ft by 9). Always confirm with the supplier whether their per-square-foot quote is on the running length × roll width or on your bare room area — the difference is the seam math the calculator handles.
Why do I need to match dye lots?
Every carpet production run produces a slightly different shade — the dye lot or batch number. Different lots installed side-by-side or as a spot repair show as visible color bands under raking light, even when the SKU is identical. Always order all carpet for one contiguous area in a single purchase order from a single dye lot, confirm the lot number on the invoice, and again on the rolls when delivered. Order a 5–10 sq yd attic-stock piece for future repairs — pet stains, burns, and seam openings need a dye-lot match years later, and reorder lots are rarely available. Stairs should share a dye lot with the adjacent room or landing — ordering them as a separate after-the-fact purchase virtually guarantees a mismatch.