How does grain line affect fabric layout?

When grain line is required, pattern pieces must be placed parallel to the selvedge (lengthwise grain). This means pieces cannot be rotated to fit more efficiently, which typically uses more fabric but ensures the garment drapes correctly.

Should I add seam allowance before or after layout?

Add seam allowance to each piece before planning the layout. This calculator adds seam allowance automatically to the dimensions you enter. The default 1.5cm seam allowance is added to all edges of each piece.

What is a good fabric utilisation percentage?

Professional pattern layouts achieve 80-90% utilisation. Home sewers typically get 65-80%. Below 60% suggests the fabric width may not suit the pattern pieces. Wider fabric or rearranging pieces can improve utilisation.

How much extra should I add for shrinkage?

Cotton typically shrinks 3-5%, linen 5-10%, and synthetics less than 1%. Pre-washing fabric before cutting eliminates this concern. This calculator adds a shrinkage allowance to the total fabric length.

Is this a true marker layout?

No. The calculator uses a greedy shelf-packing heuristic that treats every piece as a rectangle and lays them in rows widest-first. It gives a fast, slightly generous estimate of the fabric length you need. A professional marker (or careful hand layout) interlocks the actual curved shapes, flips pieces on the fold and rotates off-grain pieces where allowed, so it usually fits in less fabric. Treat the result as an upper bound and a starting point — always confirm against the layout diagram in your pattern instructions.

Pattern Layout Optimizer — Fabric Cutting Layout

Optimize fabric cutting layout to minimise waste and calculate minimum fabric length needed.

Fabric WidthBolt width of your fabric, measured selvedge to selvedge

Number of Pattern Pieces

How many pattern pieces to lay out (1-6)

Grain Line Required

Prevents rotating pieces

Piece Dimensions (length x width, cm)

Piece 1 Length

Finished length before seam allowance (added for you)

Piece 1 Width

Finished width before seam allowance (added for you)

Piece 2 Length

Finished length before seam allowance (added for you)

Piece 2 Width

Finished width before seam allowance (added for you)

How We Calculate This

This calculator estimates the minimum fabric length by packing pattern pieces into rows across the fabric width, accounting for seam allowance and shrinkage. It uses a greedy shelf-packing heuristic — pieces are treated as rectangles, sorted widest-first and laid in rows — so the figure is a quick upper-bound estimate, not a true marker layout. A hand-nested marker that interlocks curved pieces and uses the fold typically needs less.

The approach

Each piece is sized with seam allowance (added to all four edges), then packed into rows across the usable width (bolt width minus 2 cm for the selvedges).

Utilisation = Total piece area ÷ Total fabric area × 100

Frequently Asked Questions

Last updated: March 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.