How to Use the Add-A-Quarter Ruler for Perfect Quilt Seams
By Quilt in a Day - Helping Quilters Since 1978 | Published: 2026-10-29
Category: How-to Guides
Learn to use the Add-A-Quarter ruler to trim accurate 1/4-inch seam allowances for paper piecing. Step-by-step instructions and common mistakes to avoid.
Quick Answer
The Add-A-Quarter ruler helps you trim a consistent 1/4-inch seam allowance on foundation paper piecing, so your blocks fit together accurately. Use the lip against the folded paper and run your rotary cutter along the tapered edge.
Why the Add-A-Quarter Ruler Beats a Standard Ruler
A standard ruler requires you to measure and align the 1/4-inch line each time, which invites small errors that add up across many seams. The Add-A-Quarter ruler's built-in lip automatically positions the cutter at the correct distance, saving time and improving consistency.
The tapered edge helps you fold back the foundation paper without disturbing your seam, and the wider body gives you a stable grip. This makes it especially useful for paper piecing, where accuracy is critical.
Step-by-Step: Using the Add-A-Quarter Ruler
- Position the ruler on the folded paper: After sewing a fabric piece to the foundation, fold the paper back along the seam line. Place the Add-A-Quarter ruler so its lip rests snugly against the folded paper. Check that the lip is flush along the entire fold; a gap will cause a wider seam allowance.
- Trim the seam allowance: Hold the ruler firmly with one hand and run your rotary cutter along the tapered edge, cutting away the excess fabric. The lip ensures you leave exactly 1/4 inch beyond the seam. Use a sharp rotary blade and a cutting mat; a dull blade can shift the ruler.
- Fold the paper back and press: After trimming, fold the paper back to its original position and press the seam. This sets the fabric and makes the next piece easier to align. Press with a dry iron (no steam) to avoid distorting the paper.
Product Highlight
- Add-A-Quarter Ruler 12 in Plus: The specially designed lip automatically allows a 1/4-inch seam allowance at any angle for your rotary cutter. You don't have to measure each time—just butt the lip against the folded paper and cut, which speeds up piecing and reduces errors.
Add-A-Quarter Ruler 12 in Plus
