How to Calculate Quilt Border Fabric: Yardage & Cutting Guide

Two Types of Borders

Straight-cut borders

Strips sewn to opposite sides first, then top and bottom. Simplest method. Can look slightly less polished but works for most quilts.

Mitered borders

All four strips overlap at each corner and are sewn at a 45° angle. More polished but requires extra fabric (corners extend past quilt edge before mitering).

This guide covers both methods.

Straight-Cut Border Formula

For a border strip cut crossgrain (selvage to selvage, 42” WOF):

Side border strips needed = ⌈(quilt length + (border width × 2)) ÷ 42"⌉ × 2
Top/bottom border strips  = ⌈quilt width ÷ 42"⌉ × 2

Total border fabric (in)  = side_strips_per_side × (quilt length + border × 2)
                          + top_strips_per_side × quilt width
Total yards = total_fabric_in ÷ 36

Simpler approximate formula

For borders up to 6” wide on standard quilts:

Border yards ≈ (2 × (quilt width + quilt length) × border width × 2) ÷ (42 × 36)
              + 10% waste

Straight-Cut Border Examples

4” inner border — lap quilt (50×65”)

After adding a 4” border, the quilt becomes 58×73”.

Strips needed:

• Two side strips: 65” long each. 65 ÷ 42 = 1.55 → 2 strips each side = 4 strips total
• Two top/bottom strips: 50” wide. Need 2 strips (one piece each, under 42”)

Total strips = 6. Each strip is 4” wide.

Total fabric = 6 × 4" = 24" = ⅔ yard → buy ¾ yard

6” outer border — twin quilt (60×90” after inner border)

Strips needed:

• Two side strips: 90” long. ⌈90÷42⌉ = 3 per side → 6 strips
• Top/bottom: 60” wide. 2 strips needed → 4 strips

Total = 10 strips × 6” = 60” ÷ 36 = 1.67 yards → buy 1¾ yards

Mitered Border Formula

Mitered corners require the strip to extend past the quilt corner by the width of the border plus seam allowance.

Side strip length    = quilt length + (2 × border width) + 2"  (seam allowance buffer)
Top/bottom length    = quilt width  + (2 × border width) + 2"
Strips per side      = ⌈strip length ÷ 42"⌉
Total fabric (in)    = (2 strips × side length) + (2 strips × top/bottom length)
                                                                (before joining seams)
Total yards          = total fabric ÷ 36 + 10% waste

Mitered borders typically require 15–25% more fabric than straight-cut due to the corner overlap.

Border Yardage Quick Reference

All figures use 44” WOF (42” usable), straight-cut borders.

Add 25% to all figures for mitered borders.

Multiple Borders

If your quilt has both an inner and an outer border, calculate each separately and add the yardage.

Example — lap quilt (50×65”) with 2” inner + 6” outer border:

1. Inner border (2”): ⅜ yd (from chart)
2. After inner border: quilt is now 54×69”
3. Outer border (6”) on 54×69”: ⌈(69÷42)×2 + 2⌉ strips × 6” = approx. ¾ yd

Total border fabric: ⅜ + ¾ = 1⅛ yards (two different fabrics, or 1⅛ yd of one if same fabric).

Lengthwise-Cut Borders (No Seams)

For large quilts and wide borders, cutting strips lengthwise (parallel to selvage) eliminates seams in the border. Requires buying extra yardage equal to the border width plus a few inches.

Example: 6” outer border, queen quilt (90” wide after inner borders):

• Need strips 90”+ long → cut from a 6”+ lengthwise strip
• Buy: 90” + 4” seam buffer ÷ 36 = 2.6 yards. If using 4 separate strips: 1 yard per strip (quilt length ÷ 36).

Lengthwise borders eliminate the waviness that can appear when WOF-cut strips are joined.

Border Fabric with Pattern Repeat

If your border fabric has a repeating pattern (stripes, large florals), buy extra to allow matching at corner joins.

Extra yardage for repeat matching:

• Repeat length up to 6”: add ¼ yd
• Repeat length 6–12”: add ½ yd
• Repeat length over 12”: add 1 full repeat per strip

Use the Quilt Fabric Calculator for quilt top, backing, and binding — then add border yardage from this guide.

See also: Quilt Fabric Chart and How to Calculate Quilt Fabric.