How to Add Straight Borders to a Quilt. Measure three places and use the average for borders that lie flat.

Step 1: Measure the quilt in three places. For side borders, measure vertically at the left, center, and right. Lay it flat: press the quilt top and place it on a large, flat surface. Measure three times: measure top to bottom at the left, through the center, and at the right. Use the average: add the three measurements and divide by three. This is the side-border cut length.

Step 2: Cut two equal side borders. Both strips must match the calculated average length. Piece if needed: join shorter border strips with diagonal seams, then press the seams open. Cut to length: trim both side borders to the exact same three-measurement average.

Step 3: Pin the center first. Then pin both ends and the middle of each remaining section. Start in the middle: match and pin the center of the quilt edge to the center of the border strip. Then pin both ends: match and pin the two ends without stretching either layer. Divide each section: pin the middle of each section, then keep dividing and pinning while gently working in fullness.

Step 4: Sew both side borders. Use an accurate ¼-inch seam allowance. Border on top: if one layer has slight fullness, place that layer against the feed dogs. Sew slowly: remove pins as you approach them and keep raw edges aligned. Repeat: attach the second side border the same way.

Step 5: Press the side-border seams. Set the seam first, then press the border outward. Do not stretch: lift and press the iron; avoid dragging it along the border. Check it: the quilt top should lie flat with no ripples or pulled-in edges.

Step 6: Measure the new width three times. Measure across the top, middle, and bottom, including both side borders. Measure three times: measure across the top, through the middle, and across the bottom. Average and cut: add the three measurements, divide by three, and cut both borders to that average.

Step 7: Attach the top and bottom borders. Use the same mark, pin, sew, and press method. Match: pin the center first, then both ends, then the middle of each remaining section. Sew: use a ¼-inch seam and ease any fullness evenly. Press: press the top and bottom borders outward without stretching.

Finished borders should lie flat. Final check: borders are flat, corners are square, there are no waves or puckers, and measurements are recorded. Measure three times. Average. Pin center first. Ease fullness evenly.