Yardage and meterage by fabric width

The same pieces can need very different lengths on different bolt widths. Enter one repeated rectangle, or load the project from the planner, to compare every common width side by side.

Units

Piece width

Piece length

Quantity

Seam allowance to add

Selvage each side

Shrinkage (both ways) %

Grain

Nap / one-way print

Bolt width	Usable	Used length	Buy (rounded up)	Waste

Purchase lengths are rounded up to ⅛ yd or 10 cm and include shrinkage. They don't include extra for straightening a crooked cut end or for flaws, which many sewists add. Layouts come from the same rectangle-packing heuristic as the planner.

Reading the table

Usable width is the bolt width minus both selvages and width shrinkage. A "44 in" quilting cotton often has only about 40–42 in usable once the selvages are trimmed (source), so measure yours.
Going wider doesn't always help. Gains come in steps: one more piece has to fit across the width before the length drops.
Compare cost as well as length: wider fabric usually costs more per yard or metre.