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Quilt Fabric Calculator

Walk through each step to calculate fabric yardage for your quilt project

Quilt Size
Blocks
Borders & Binding
Results
1
2
3
4
Step 1 of 4: Quilt Size

Quilt Size

Choose a standard quilt size or enter custom dimensions

Steps

Results
Total Fabric Needed
5.9 yards
42" × 54" finished quilt · 12 blocks
Block Layout
3 × 4
12 total blocks
Backing
3.8 yd
2 panels

Block Fabrics (5 colors)

Fabric 10.38 yd(3 blocks)
Fabric 20.38 yd(3 blocks)
Fabric 30.38 yd(3 blocks)
Fabric 40.38 yd(3 blocks)
Fabric 50.38 yd(3 blocks)
Block Fabric Total1.91 yd

Additional Fabrics

Border 10.11 yd
Binding0.09 yd
Backing3.79 yd
Batting50" × 62"(2.4 sq yd)

Shopping List Summary

Block fabrics (5 colors)1.91 yd
Border fabric(s)0.11 yd
Binding fabric0.09 yd
Backing fabric3.79 yd
Grand Total (incl. 10% waste)5.90 yd

Tips

  • • All yardage assumes 42" wide quilting cotton (WOF)
  • • 10% waste factor included for shrinkage and cutting errors
  • • Pre-wash fabric before cutting to account for shrinkage
  • • Backing requires 2 panels seamed together
  • • Buy an extra 1/4 yard of each fabric for a scrappy look or test squares

Frequently Asked Questions

Q

How much fabric do I need for a throw quilt?

A throw quilt (50" x 65") with 12-inch blocks and 5 fabrics needs about 5-6 yards total, including block fabrics, borders, binding, and backing. Backing alone requires 3-4 yards since most quilting cotton is only 42 inches wide.

  • Block fabric: ~0.38 yd per fabric × 5 fabrics = ~1.9 yd total for 12 blocks
  • Backing: 3–4 yd (requires 2 panels seamed for a 50"-wide quilt)
  • Binding: ~0.4 yd for a 292" perimeter with 2.5" strips
  • Border fabric: ~0.75 yd for a single 3" border on all sides
  • Always buy 10% extra — quilting cotton shrinks 3–5% after pre-washing
Q

How do you calculate quilt yardage from block size?

Add 0.5 inches seam allowance to each block side, then figure how many blocks fit across 42-inch-wide fabric. Divide blocks per fabric by blocks per strip, multiply by the cut size, and convert to yards. Always add 10% for waste and shrinkage.

  • A 12" finished block needs a 12.5" cut square (0.25" seam allowance per side)
  • 42" fabric width fits 3 blocks at 12.5" each (42 ÷ 12.5 = 3.36, floor to 3)
  • A 10" block (10.5" cut) fits 4 per strip across 42" fabric
  • Multiply strip count × cut size, then divide by 36 to convert to yards
  • Add 10% waste factor: multiply final yardage × 1.10 before purchasing
Q

Why do quilters add seam allowance to fabric calculations?

Quilters add 1/4 inch seam allowance on each side of every block (0.5 inches total per dimension). A 12-inch finished block requires a 12.5-inch cut square. Without seam allowance, your finished blocks will be undersized and your quilt will come out smaller than planned.

  • Standard quilting seam allowance is 1/4" per edge (0.5" per dimension)
  • A 6" finished block cuts at 6.5"; a 12" block cuts at 12.5"
  • Forgetting seam allowance on a 20-block quilt can shrink it by 10" in each direction
  • Use a 1/4" presser foot for consistent seams — even 1/16" error compounds across blocks
  • Sashing strips also need seam allowance: a 2" finished sash cuts at 2.5"
Q

How much backing fabric do I need for a queen quilt?

A queen quilt (86" x 96") needs backing fabric at least 94" x 104" (adding 4 inches overhang per side). Since quilting cotton is 42" wide, you need 3 panels seamed together, totaling about 9 yards of backing fabric with waste allowance.

  • Add 4" overhang per side: 86" quilt needs 94" of backing width
  • 42" fabric width means 3 panels needed (3 × 42" = 126" covers 94" width)
  • Each panel must be the full quilt length + 8" overhang = 104" (2.89 yd)
  • Total: 3 panels × 2.89 yd = 8.67 yd + 10% waste = ~9.5 yd
  • Wide-back fabric (108") eliminates seaming — needs only 3 yd but costs $15–$20/yd vs $8–$12/yd
Quilt SizeBacking (42" fabric)PanelsWide-back (108")
Baby (36×52")1.8 yd11.7 yd
Throw (50×65")3.8 yd22.1 yd
Queen (86×96")9.1 yd32.9 yd
King (104×92")10.8 yd32.8 yd

Example Calculations

1Throw Quilt with 12" Blocks

Inputs

Quilt SizeThrow (50" × 65")
Block Size12 inches
Number of Fabrics5
SashingNone
Border 13 inches
Binding Width2.5 inches

Result

Total Fabric Needed5.9 yards
Block Layout3 × 4 (12 blocks)
Per Fabric0.38 yd each (3 blocks)
Backing3.79 yd (2 panels)
Finished Size42" × 54"

Inner area = 44" × 59" after subtracting 3" borders. Fits 3 × 4 = 12 blocks. Each fabric gets ceil(12/5) = 3 blocks. Cut size is 12.5", 3 fit per WOF strip, so 1 strip per fabric = 0.38 yd each. Backing needs 2 panels at 62" long = 3.79 yd.

2Queen Quilt with 10" Blocks & Sashing

Inputs

Quilt SizeQueen (86" × 96")
Block Size10 inches
Number of Fabrics6
Sashing2 inches
Border 13 inches
Border 21.5 inches
Binding Width2.5 inches

Result

Total Fabric Needed13.3 yards
Block Layout6 × 7 (42 blocks)
Per Fabric0.64 yd each (7 blocks)
Backing9.08 yd (3 panels)
Finished Size79" × 91"

Inner area = 77" × 87" after two borders. With 2" sashing, cell size = 12", fitting 6 × 7 = 42 blocks. Each of 6 fabrics gets 7 blocks. Cut size 10.5", 4 per strip, 2 strips needed = 0.64 yd per fabric. Backing needs 3 panels for the 87" width.

Formulas Used

Block Fabric Yardage

Yardage = (ceil(Blocks / floor(42 / CutSize)) × CutSize / 36) × 1.10

Calculates fabric yardage per fabric color, where CutSize = BlockSize + 0.5" seam allowance. Divides blocks among strips that fit across the 42" fabric width, with 10% waste factor.

Where:

Blocks= Number of blocks assigned to this fabric color
CutSize= Block size plus 0.5" seam allowance (e.g., 12.5" for 12" blocks)
42= Standard quilting cotton width off the bolt (WOF) in inches
1.10= 10% waste factor for cutting errors and shrinkage

Backing Yardage

Backing = (ceil(QuiltWidth + 8) / 42) × (QuiltLength + 8) / 36 × 1.10

Calculates backing fabric by adding 4" overhang per side, then determining how many 42" panels are needed to cover the width. Each panel must be the full quilt length.

Where:

QuiltWidth= Finished quilt width in inches
QuiltLength= Finished quilt length in inches
8= Total overhang: 4 inches per side for quilting margin
42= Fabric width off the bolt in inches

Binding Yardage

Binding = ceil((2 × (W + L) + 12) / 42) × CutWidth / 36 × 1.10

Calculates binding fabric from the quilt perimeter plus 12" for seam joins and finishing overlap, cut into strips from the fabric width.

Where:

W= Finished quilt width in inches
L= Finished quilt length in inches
12= Extra inches for joining strips and overlap
CutWidth= Binding strip cut width plus 0.5" seam allowance

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Last Updated: Mar 9, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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