Directional Fabric Calculator — One-Way Print & Nap Allowance
Calculate extra fabric needed when using directional prints, napped fabrics, or large pattern repeats.
How We Calculate This
Directional fabrics require all pattern pieces to be laid out in one direction, which wastes more fabric. These tiers are approximate rules of thumb — always use the “with nap” yardage printed on your pattern envelope when one is given. If it is not, the common convention is to add about 20% to the standard requirement for any napped or one-way fabric.
- Slight directional: +10%
- One-way print: +15%
- Nap/pile (velvet, corduroy): +20%
- Large pattern repeat / plaid: +25% (12″+ repeats can need up to 50%)
Narrower bolts also nest one-way pieces less efficiently, so this tool adds a small extra allowance on 137 cm and 112 cm widths compared with wide 150 cm cloth.
The formula
Total fabric = Base × (1 + Directional% + Width%) × (1 + Shrinkage%) + Selvedge
The core estimate is Base × (1 + Extra%); the shrinkage factor and flat selvedge allowance (both in Advanced Options) are then applied and the result is rounded up to the nearest 0.1 m.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates. Always verify quantities before cutting or purchasing fabric.