A fitted sheet is a flat sheet with elastic sewn into the corners
A fitted sheet stays on the mattress because elastic is stitched into the four corner pockets. You start with a flat rectangular piece of fabric, sew a casing (a tube of fabric) around the perimeter, thread elastic through that casing, and stitch the ends closed. The elastic pulls the corners down and under, creating the fitted shape. This is not a difficult project—the hardest part is keeping the fabric flat while you sew the casing, not the sewing itself.
You will need a sewing machine, thread, elastic, fabric scissors, a measuring tape, pins, and a needle for hand-stitching the final seam. Most people use 1-inch-wide elastic for a standard mattress. The fabric should be large enough to wrap around your mattress with 2 to 3 inches of overlap on all sides—for a queen mattress, that is roughly 90 by 100 inches of fabric.
Key Takeaways
- Cut your fabric to size, then fold and pin a 2-inch casing around all four edges before sewing it down.
- Thread elastic through the casing using a safety pin, then overlap and stitch the elastic ends together by hand.
- Stitch the casing opening closed by hand after the elastic is in place, using a ladder stitch or whip stitch.
- Test the fit on your mattress before trimming excess fabric, since mattress sizes vary slightly.
- A basic fitted sheet takes two to three hours if you have sewing experience, longer if you are new to a machine.
Measure and cut your fabric to the right size
Measure your mattress length, width, and depth. Add twice the depth plus 4 inches to both the length and width. For example, a queen mattress is 60 inches wide and 80 inches long, with a depth of about 12 inches. You would cut fabric 60 + (2 × 12) + 4 = 88 inches wide and 80 + (2 × 12) + 4 = 108 inches long. This gives you enough fabric to wrap under the mattress and create the corner pockets.
Lay your fabric on a large, flat surface and mark these dimensions with a pencil or fabric pen. Use a straightedge or measuring tape to keep your lines even. Cut along your marked lines with sharp fabric scissors. If your fabric is smaller than your mattress, you can piece two lengths together by sewing them with a 1/2-inch seam allowance, but a single piece is simpler.
Fold and pin a 2-inch casing around all four edges
Fold one long edge of the fabric toward the wrong side (the back) by 2 inches. Press the fold flat with your fingers or an iron. Pin the fold in place every 3 to 4 inches. Repeat this on the opposite long edge, then on both short edges. You now have a 2-inch border folded under on all four sides, and the fabric is smaller by 4 inches in each direction.
At each corner, the two folds will overlap. Fold the corner so that both edges meet at a 45-degree angle, creating a neat diagonal line. Pin this corner fold in place. The corner should look like a small triangle pointing outward. This is where the elastic will sit and create the pocket that holds the fitted sheet on the mattress.
Sew the casing with a straight stitch 1/2 inch from the folded edge
Thread your sewing machine with thread that matches your fabric. Set the machine to a straight stitch with a medium stitch length (about 2.5 on most machines). Starting at one corner, sew along the folded edge, keeping the needle 1/2 inch from the fold. Sew slowly around all four sides, removing pins as you approach them. Backstitch at the beginning and end to lock the thread.
Leave a 3-inch opening on one side—do not sew all the way around. This opening is where you will thread the elastic through. When you reach the opening, backstitch, cut the thread, and lift the presser foot. Move to the other side of the opening and resume sewing, backstitching to lock the thread again. This creates a continuous casing with one gap.
Thread elastic through the casing using a safety pin
Cut a length of 1-inch-wide elastic. The length should be the perimeter of your mattress minus 8 inches. For a queen mattress with a 60-inch width and 80-inch length, the perimeter is 280 inches, so you would cut elastic about 272 inches long. Attach a safety pin to one end of the elastic and feed it through the opening in the casing, working it around all four sides.
Push the safety pin and elastic slowly through the casing. The fabric will bunch up as you go—this is normal. When the elastic reaches the opening again, you will have a loop. Overlap the two ends of the elastic by 1 inch and pin them together. Try the fitted sheet on your mattress to check the fit. The corners should pull snug and stay in place. If the fit is too tight or too loose, adjust the overlap before stitching.
Stitch the elastic ends together and close the casing opening
Once the fit is correct, stitch the overlapped elastic ends together by hand using a needle and thread. Use a zigzag stitch or multiple passes back and forth to make the seam strong. The elastic will be under tension, so reinforce this seam well. Cut off any excess elastic that sticks out beyond the overlap.
Now close the 3-inch opening in the casing by hand. Thread a needle and use a ladder stitch (also called a whip stitch). Fold the raw edges of the opening inward by 1/2 inch and pin them together. Slide the needle through the fold on one side, then through the fold on the opposite side, moving along the opening. Pull the thread every few stitches to close the gap. When you reach the end, tie off the thread on the inside of the casing.
Test the fit and trim any excess fabric
Put the fitted sheet on your mattress and check that all four corners pull down evenly and stay in place. The fabric should be snug but not so tight that it is hard to remove. If one corner is looser than the others, the elastic may not be centered in the casing—you can adjust it by opening the casing slightly and shifting the elastic.
Once the fit is correct, trim any excess fabric that hangs below the mattress. Leave about 1/2 inch of fabric below the elastic so the sheet does not slip. If the fabric is fraying, you can seal the raw edges with a zigzag stitch on your sewing machine or explore a thin line of fabric glue. Wash the sheet in warm water before using it to soften the fabric and set the elastic.
Frequently Asked Questions
Can I use a different width of elastic?
Yes. Wider elastic (1.5 inches) creates a deeper pocket and is easier to thread, but it uses more fabric in the casing. Narrower elastic (3/4 inch) uses less fabric but may not hold as securely on a thick mattress. Test on a corner before committing to the full sheet.
What if my fabric is not large enough for a single piece?
You can sew two pieces together along the length or width using a 1/2-inch seam allowance. Press the seam flat and trim the excess. The seam will be hidden inside the casing, so it does not affect the appearance. Make sure the grain of the fabric runs the same direction on both pieces.
How do I keep the casing from puckering when I sew it?
Pin the fold every 2 to 3 inches instead of every 4 inches, and sew slowly. If puckering still happens, you can gently pull the fabric taut as you sew, but do not stretch it. Pressing the fold with an iron before sewing also helps keep it flat and even.
What stitch should I use if my machine has trouble with the corners?
A straight stitch works best, but if your machine skips stitches at the thick corner folds, try a slightly longer stitch length (3.0 instead of 2.5) and sew more slowly. You can also reduce the presser foot pressure if your machine has that option, which helps the fabric feed evenly.
Can I use pre-made elastic casing instead of folding the fabric?
Pre-made casing (a tube of fabric with openings) exists, but it is harder to find and more expensive than sewing your own. Folding the fabric edge is the standard method and gives you full control over the casing width and appearance.