1. Identify the Fabric Selvage

• Locate the selvage edge, which is the tightly woven finished edge running along both lengthwise sides of the fabric.
• The selvage often contains manufacturer information, colors dots, or a different texture than the rest of the fabric.
• The selvage runs parallel to the lengthwise grain (also called the straight grain or warp threads).

2. Understand Lengthwise Grain (Warp)

• The lengthwise grain runs parallel to the selvage from one end of the fabric to the other.
• These are the warp threads, which are held taut on the loom during weaving.
• Lengthwise grain has the least amount of stretch and provides the most stability.
• Most garment pieces are cut with the lengthwise grain running vertically (top to bottom) to prevent sagging and maintain shape.
• Pull gently on the lengthwise grain; you’ll feel minimal give.

3. Understand Crosswise Grain (Weft)

• The crosswise grain runs perpendicular to the selvage, from selvage to selvage.
• These are the weft threads, which are woven over and under the warp threads.
• Crosswise grain has slightly more stretch and give than lengthwise grain.
• Some pattern pieces, like waistbands or binding strips, may be cut on the crosswise grain for economy or slight ease.
• Pull gently on the crosswise grain; you’ll feel a bit more stretch than lengthwise.

4. Understand Bias Grain

• The bias runs at any diagonal angle to the lengthwise and crosswise grains.
• True bias is at exactly 45 degrees to both the lengthwise and crosswise grains.
• Bias has maximum stretch, drape, and flexibility because you’re pulling across the woven threads rather than along them.
• Bias-cut garments (like bias skirts or bias binding) hug curves beautifully and have fluid movement.
• Bias strips are used for binding curved edges, piping, and decorative trims because they can bend smoothly without puckering.
• Pull gently on the true bias; the fabric will stretch significantly and recover when released.

5. Check if Fabric is On-Grain

• Fold the fabric in half lengthwise, matching selvages.
• Check if the crosswise threads form a perfect right angle (90 degrees) to the selvage; if they do, the fabric is on-grain.
• If the fabric is off-grain (skewed), the crosswise edge will not align and the fabric may look twisted.
• To correct off-grain fabric, gently pull on the true bias in the opposite direction of the skew until crosswise threads are perpendicular to the selvage.
• Press the fabric flat to set the corrected grain.

6. Find and Mark the Grainline on Pattern Pieces

• Every pattern piece includes a grainline arrow, typically a long straight line with arrows at both ends.
• The grainline arrow must be placed parallel to the selvage (lengthwise grain) unless the pattern specifies otherwise.
• Lay the pattern piece on the fabric and measure from one end of the grainline arrow to the selvage.
• Measure from the other end of the grainline arrow to the selvage; both measurements must be identical to ensure the pattern is on-grain.
• Pin the pattern in place only after confirming grainline alignment.

7. Understand Fabric Types and Structure

• Woven fabrics: Created by interlacing lengthwise (warp) and crosswise (weft) threads at right angles; examples include cotton quilting fabric, denim, linen, and twill.
• Knit fabrics: Created by interlocking loops of yarn; examples include jersey, rib knit, and interlock; knits stretch significantly across the width and have recovery along the length.
• Non-woven fabrics: Created by bonding or felting fibers together without weaving or knitting; examples include felt, interfacing, and Ultrasuede; these fabrics have no grainline.
• Napped or directional fabrics: Some fabrics have a pile (like velvet or corduroy) or a one-way print; these require all pattern pieces to be cut in the same direction regardless of grainline.

8. Practice Identifying Grainlines

• Take a scrap of woven fabric and pull gently in all directions—lengthwise, crosswise, and bias—to feel the difference in stretch and stability.
• Mark the selvage, lengthwise grain, crosswise grain, and true bias (45 degrees) with chalk or a washable marker.
• Cut small swatches on each grain and observe how they behave when draped, pulled, or sewn.
• Repeat with knit fabric to understand how courses and wales differ from woven grainlines.

9. Apply Grainline Knowledge to Your Project

• Before cutting any pattern, double-check that the fabric is on-grain and pressed flat.
• Align each pattern piece according to the grainline arrow, measuring carefully from the selvage.
• Pin pattern pieces securely and cut with sharp scissors or a rotary cutter for accuracy.
• Transfer all pattern markings (notches, darts, placement lines) to the fabric before removing the pattern.
• As you sew, observe how the fabric behaves on different grainlines and adjust tension or stitch length if needed.