Fabric Calculator

Formula

Fabric length = panel length × panel width × pieces ÷ roll width × (1 + allowance percentage), with centimeters converted to meters.

Worked example

With Panel length: 120 cm, Panel width: 60 cm, Number of pieces: 4, Fabric roll width: 150 cm, Cutting allowance: 15 %, estimated fabric length is 2.208 m.

Inputs and calculation

Multiply each rectangular piece's length by its width, multiply by the quantity, then divide the total area by the roll width. Convert centimeters of resulting roll length into meters and apply the chosen cutting allowance. The displayed relationship is Fabric length = panel length × panel width × pieces ÷ roll width × (1 + allowance percentage), with centimeters converted to meters. Keep the fields' displayed units attached when reproducing this relationship by hand.

Worked numerical example

For example, enter panel length 120 cm, panel width 60 cm, number of pieces 4, fabric roll width 150 cm, cutting allowance 15 %. Those inputs produce estimated fabric length of 2.208 m.

Holding the other example values fixed, change panel length from 120 to 132 cm. The main output becomes 2.4288 m. This comparison isolates the effect of that one input.

How to read and use the result

This is an area-based lower-bound purchase estimate. The answer says how much linear fabric a perfect, zero-gap layout would consume after the entered allowance; actual placement may require more roll length. Compare fabrics sold by the linear meter and estimate a first purchase quantity for repeated rectangular panels.

Practical context

Suppose each panel needs to keep its printed pattern upright. Pieces can no longer be rotated to fill every gap, so an area calculation may substantially understate the roll length.

Assumptions and scope

All pieces are rectangles, share the entered dimensions and use one consistent roll width. Grain direction, print matching and irregular cutouts are outside the formula. Replace the example defaults with measured inputs for your situation and account separately for factors outside these fields.

Checks and common mistakes

A wide piece may not fit across the roll despite sufficient total area. Draw a cutting layout before ordering, especially for directional fabric, seams, stripes or repeating patterns.

Common questions

What should I verify before using the Fabric Calculator result?

A practical check is to sketch the panel rectangles across the roll width and count rows along the length. For upholstery, add seam allowances to panel dimensions before entering them; for curtains, include hems and pattern repeats. Buy from one dye lot if color consistency matters, and verify whether the shop sells fabric by meter or yard.