Carpet Calculator — Roll Length, Layout & Cost
Compare two carpet layouts, allow for edge trimming, and estimate roll length and costs from your supplier’s quotes.
40½ ft of carpet roll for the example layout
Example: a 20 × 14 ft room, 12 ft roll, 1½ in trim at each wall and quarter-foot order increments. Two 20¼ ft drops need 40½ ft of roll before any supplier minimum.
Compare quantities, then choose the pile direction and seam plan with your installer. Less material does not automatically mean a better installation.
Room and supplier measurements
Changing display units preserves your measurements and quote units.
Edge trim is the combined width removed from both edges of every drop. Zero assumes the whole nominal width is usable. Confirm usable width and allowances before ordering.
A single nominal pattern repeat cannot guarantee matching. Ask your installer for a matched cut length for each orientation, including wall trim and pattern allowance. Also confirm the usable width above.
Add your price quotes
Leave unknown prices blank. Use 0 only for free or unnecessary items. Changing currency clears all prices; changing a quote unit clears its prices. No currency conversion is applied.
Compare the two directions
Where the excess goes
These parts add up to purchased area minus floor area. Trimming and matching allowance are not necessarily reusable pieces.
How much carpet should you buy?
A room’s floor area is not the same as the carpet you purchase. Broadloom comes at a fixed width. Measure the room’s widest extents, include recesses and openings that need carpet, and ask your supplier for the actual usable width after trimming the edges.
For each orientation, add the wall allowance at both sides of the room. Divide this span by usable roll width and round up to whole drops. Each drop’s length is the other room dimension plus trim at both ends. Multiply the number of drops by their cut length, then apply the supplier’s minimum order and sale increment.
Example: a 20 × 14 ft room
With a 12 ft usable roll width and 1½ in at each wall, either direction needs two drops. Along the 20 ft dimension, cut two 20¼ ft lengths: 40½ linear ft. Along the 14 ft dimension, cut two 14¼ ft lengths: 28½ linear ft. At quarter-foot increments and no minimum, those are also the order lengths. The floor is 280 ft²; the two purchases are 486 ft² and 342 ft² respectively. These are illustrative allowances, not a specification for every product.
Will a 12 ft wide room fit a 12 ft roll?
Only if the usable width and allowances permit it. Edge trimming reduces usable width and wall trimming increases the required span. Even a room exactly 12 ft wide can need more than one drop. Do not assume nominal width is usable width.
Does the pattern option guarantee matching?
No. It uses installer-confirmed cut lengths for the two orientations. Pattern size, transverse alignment, roll variation and edge cuts must be checked for the actual product. All drops keep the same pile direction; the tool does not rotate offcuts or optimize patched layouts.
What is excluded?
This is one rectangular room with parallel seams and no end joins. Stairs, L-shaped layouts, joint planning between rooms, adhesive, grippers, removal, taxes and contractor minimums are not inferred. Confirm the final layout and product instructions before cutting. Underlay cost uses the entered floor-area rate; its own roll quantities are not calculated.
Manufacturer guidance: Bentley Mills broadloom installation guide explains edge preparation, pile direction and product-specific pattern sequencing. Knotistry’s measuring guide illustrates widest-point measurement and supplier-specific ordering rules. Their allowances are not universal.
Comparing hard floors? Use the tile calculator for tiles and boxes, or the laminate flooring calculator to plan rows and a shared carton order across rooms. Estimate decorating materials separately with the paint calculator.
