Quick answer
To square up quilt blocks, press the block flat, align the ruler's reference lines with the block's center seams, and trim one or two sides at a time. Using a dedicated ruler like the Sew Square 6 makes this faster because its printed square-up lines match specific Sew Kind of Wonderful patterns.
Why squaring up matters for perfect quilt blocks
Squaring up removes uneven edges and ensures every block is the same size, which is critical for seams to nest and points to match. Even a small 1/8-inch difference can throw off an entire quilt top. Trimming after pressing is the only reliable way to correct stretch or distortion from piecing.
Tools you need before you start
You'll need a rotary cutter with a sharp blade, a cutting mat, and a square ruler. For curved piecing patterns, a specialty ruler like the Sew Square 6 provides pattern-specific square-up lines that align with Mini Rings, Mini Picnic, Mini Country, and Chic Country/Country Revival. If you're making the Posh Penelope quilt, the Posh Penelope Combo includes both the pattern and the necessary ruler, saving you from guessing which tool to use.
Step-by-step: squaring up a standard quilt block
Follow these steps for any block that finishes as a square. The process is the same whether you're trimming half square triangles or a nine-patch.
Step-by-step squaring up process
- Press the block, don't iron: Set the seams with a dry iron, then press the block flat from the front and back. Avoid sweeping the iron, which can stretch bias edges. Mistake to avoid: ironing back and forth can distort the block before you even trim.
- Place the ruler with reference lines on seams: For Sew Square 6, match the appropriate square-up lines (e.g., Mini Rings or Chic Country) to the block's seams. The lines are labeled with pattern names and sample numbers. Checkpoint: the ruler should sit squarely without rocking; if it rocks, your block may be cupped.
- Trim one side at a time: Trim the right and top edges first, then rotate the block 180 degrees and trim the remaining two sides to the final size. Use a fresh blade for clean cuts. Mistake to avoid: trying to trim all four sides at once often leads to slipping and inaccurate cuts.
- Verify size and repeat: Measure the trimmed block against your pattern's required size. If it's off, check your seam allowance and re-press before trimming again. Next step: stack and chain-trim multiple blocks to save time once you're confident.
Product facts
- Sew Square 6: Sew Square 6 is a 6" x 6" clear acrylic ruler with easy to use black lines and marks. It includes reference lines for Mini Rings square-up lines (Sample 13 in pattern, page 3), Mini Picnic square-up lines (Sample 10 in pattern, page 3), Mini Country square-up points (Sample 13 or 14 in pattern, page 3), and Chic Country & Country Revival square-up points (Sample 14 in pattern, page 3). These pattern-specific lines let you align the ruler exactly where the pattern designer intended, reducing guesswork and helping you achieve consistent block sizes across these projects.
- Country Revival (Paper): Country Revival (Paper) pattern requires 44" x 44" (8) fat quarters assorted prints (teal), 1-1/3 yards background fabric (white), 1-1/2 yards setting fabric (gray), 3 yards backing, 1/2 yard binding. A Quick Curve Ruler Chic Country video tutorial is available on the Sew Kind of Wonderful YouTube channel and also works for Country Revival. If you're making Country Revival, you can use the Sew Square 6's Chic Country & Country Revival square-up points to trim blocks accurately. The video tutorial provides additional visual guidance for curved piecing.
- Posh Penelope Combo: Posh Penelope Combo includes the Posh Penelope pattern (winner of the 2025 March Madness Event) and the necessary ruler. It is described as a stash buster quilt pattern and a perfect gift for a quilter. This combo ensures you have the correct ruler for the pattern, so you can square up blocks without buying tools separately. It's a convenient option if you want to start a new project with everything you need.
