Three Strips Quilt Block Pattern

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How to Sew a Three Strips Quilt Block

The Three Strips quilt block is a simple and quick design using three fabric strips in different colors sewn together, then cut into sections and reassembled with the middle piece flipped to create a classic alternating stripe pattern. It's a great beginner block and a wonderful way to use up fabric scraps!

Materials Needed

• Three fabric strips in different colors, each 2½" wide × at least 16" long
• Sewing machine and thread
• Scissors
• Iron and ironing board
• Cutting mat and ruler

Step-by-Step Instructions

1. Choose three fabric strips in the colors you want for your block.
2. Lay the three strips right sides together, one on top of the other.
3. Sew a ¼" seam along one long edge of the strips. Press the seams open with an iron.
4. Lay the sewn strip flat on your cutting mat with seam allowances facing up.
5. Cut the strip set into three sections, each 5½" wide.
6. Flip the middle section around so the colors alternate on each side of the center piece.
7. Sew the three sections together by placing the outer sections right sides together with the center section. Sew a ¼" seam along each long edge, making sure to match the seams.
8. Press the seams open with an iron.

Congratulations — your Three Strips quilt block is complete! Repeat these steps to create more blocks, then join them together to build a larger quilt top.

How to Resize Quilt Blocks

The first step in modifying any quilt block is to decide on your finished block size. You can base this on doubling a pattern, cutting it in half, or working with your available fabric.

Note: When working from a pattern's cutting instructions, remove the seam allowance before scaling. For example, if your pattern calls for 3½″ squares, subtract the seam allowance (½″), double the finished size (3″ → 6″), then add the seam allowance back (½″) — giving you a 6½″ cut piece.

Resizing Square Blocks

Add ½″ to your finished block measurement. For a 4″ finished square, cut a 4½″ square of fabric.

Resizing Rectangular Blocks

Add ½″ to both the length and width. To double a 3″ × 4″ block, cut a 6½″ × 8½″ rectangle.

Resizing Half-Square Triangle Blocks

Add 7/8″ to the desired finished block size. For a 4″ finished HST block, cut 4⅞″ squares.

Resizing Quarter Square Triangle Blocks

Add 1¼″ to the desired finished block size. For a 4″ finished block, cut 5¼″ squares.