Snowball Quilt Block Pattern

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How to Sew a Snowball Quilt Block

The Snowball quilt block is a simple and classic pattern that’s perfect for beginners. Its rounded corners create a beautiful effect when blocks are sewn together.

Materials:

• 1 fabric square for the center
• 4 fabric squares for the snowball corners
• Sewing machine & fabric scissors
• Ruler & iron and ironing board

Cut your fabric:

• Center square: 4½"
• Corner squares: four 2½" squares

Instructions:

1. Place one corner square onto a corner of the center square, right sides facing. Sew diagonally across the corner square using a scant ¼" seam allowance.
2. Press the seam toward the corner square, then trim the excess fabric leaving a ¼" seam allowance.
3. Repeat steps 1–2 for the remaining three corners.
4. Press all seams toward the corner squares.
5. Your Snowball block is complete! Repeat to make as many blocks as needed.

Tips:

• Use a scant ¼" seam allowance to prevent the block from becoming too small.
• Press seams as you go to ensure accuracy and prevent puckering.

Making Half-Square Triangles

On the back of the lighter fabric, draw a pencil line diagonally from corner to corner.

Stack a pair of light and dark squares right sides together. Sew a ¼" seam allowance on each side of the line.

You will end up with something like this:

Now cut along the diagonal line.

Press the seam to set it, then press toward the darkest fabric.

To trim to the exact size, line up the 45° diagonal on your ruler with the seam.

Then carefully trim your block with a rotary cutter.

How to Resize Quilt Blocks

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

Important: Always remove the seam allowance before doubling or tripling the size. For example, if your pattern calls for 3½" squares, subtract the seam allowances (½"), double the finished block size (3" → 6"), then add the seam allowance back (½"). You’ll end up cutting a 6½" piece of fabric.

Resizing Square Blocks

Add ½" to your desired 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 block that measures 3" × 4", cut a 6½" × 8½" rectangle of fabric.

Resizing Half-Square Triangle Blocks

Add ⅞" to the desired finished block size. For a 4" finished block, cut 4⅞" squares.

Resizing Quarter-Square Triangle Blocks

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