Snaps are faster to close than buttons and easier to sew than zippers
A snap is a two-part fastener: a ball (the raised side) and a socket (the recessed side). The ball presses into the socket and holds fabric closed. You sew one half to each side of the opening—the ball side on top, the socket side underneath. Hand-sewing a snap takes about five minutes once you know where to place it and how to anchor the thread.
Snaps work best on lightweight to medium-weight fabrics like cotton, linen, and knits. They are common on baby clothes, children's jackets, and the cuffs of work shirts. Unlike buttons, snaps do not create a visible hole or gap, and they do not come undone as easily if you catch them on something.
Key Takeaways
- Snaps come in two halves—a ball and a socket—and you sew the ball to the top layer of fabric and the socket to the bottom layer.
- Mark the snap placement with a pencil or fabric pen before you sew, measuring from the edge of the opening so both halves line up.
- Use a needle and thread that match your fabric, and sew through the four small holes in each snap half with small, tight stitches.
- Test the snap by pressing it closed before you cut your thread, so you can adjust placement if it does not catch properly.
Gather your materials and choose the right snap size
You will need a needle, thread that matches your fabric, a snap kit or individual snaps, and a pencil or fabric pen. Snaps come in several sizes, usually labeled by diameter in millimeters or by garment type. Size 16 (about 10 mm) is standard for children's clothing and lightweight fabrics. Size 20 (about 12 mm) works for medium-weight fabrics and adult garments. Larger snaps (size 24 and up) are for heavy coats and work wear.
Buy snaps at fabric stores, online retailers, or in the notions section of craft stores. They come loose or on a strip. A snap kit usually includes a tool to set snaps with pressure, but hand-sewing works just as well and gives you more control over placement. Thread should be strong—all-purpose polyester or cotton thread rated for your fabric weight is fine. If your fabric is dark, use dark thread; if light, use light thread.
Mark the snap placement on your fabric
Lay your garment flat with the opening closed as it will be when worn. Decide where you want the snap to sit—usually about half an inch from the edge of the opening, centered left to right. Use a pencil or fabric pen to mark a small dot on the top layer where the ball will go. Then mark a dot on the bottom layer directly underneath it, where the socket will go. If you are sewing multiple snaps in a row, measure the distance between them and mark all of them before you start sewing.
The marks do not need to be exact, but they should be aligned so the ball and socket meet when you press the fabric closed. If the marks are off by more than a quarter inch, the snap will not catch properly and you will have to remove it and start over.
Sew the ball half to the top layer
Thread your needle and tie a knot at the end. Bring the needle up through the fabric from underneath, coming out right at your pencil mark. Place the ball half of the snap on top of the fabric with the four small holes facing down. Push the needle through one of the holes in the snap, then back down through the fabric next to it. Come back up through the next hole and repeat.
Sew through each of the four holes twice—that is, eight stitches total. Keep your stitches small and tight; they should be barely visible from the top of the fabric. After the eighth stitch, bring the needle to the underside of the fabric and tie off the thread with a small knot. Trim the thread close to the knot. The ball should now be firmly attached and should not wiggle when you tug it.
Sew the socket half to the bottom layer
Thread your needle again and tie a knot. Flip the garment over or fold it so you can access the bottom layer at your second pencil mark. Bring the needle up through the fabric at the mark. Place the socket half (the recessed side) on top with the four holes facing down. Sew through each hole twice, just as you did with the ball, keeping stitches small and tight.
After eight stitches, bring the needle to the underside and tie off with a knot. Trim the thread. The socket should sit flat against the fabric and should not move when you press on it. If either half is loose, the snap will not hold or will pop open too easily.
Test the snap before you finish
Close the opening of your garment and press the ball and socket together. They should click or snap into place with a firm, satisfying feel. If they do not catch, or if one side feels loose, you may need to resew. If the snap is slightly misaligned, you can often adjust it by loosening one side and moving it a quarter inch in the direction needed.
If the snap is too loose to hold, the stitches may not be tight enough. Remove the snap by cutting the thread on the underside and pulling the snap away. Sew it back on with smaller, tighter stitches, going through each hole three times instead of twice. If the snap is too stiff or hard to close, you may have sewn it too tightly—this is rare, but if it happens, try a slightly larger snap size next time.
Remove and replace a snap if needed
If a snap fails or you sewed it in the wrong place, you can take it out. Cut the thread on the underside of the fabric with small scissors or a seam ripper. Gently pull the snap away from the fabric. Use tweezers to pick out any remaining thread bits. The holes in the fabric will be small and usually not visible once the snap is gone.
If the holes are enlarged or the fabric is torn, you can sew the new snap slightly offset from the old holes, or you can reinforce the area with a small patch of interfacing on the underside before sewing the new snap. For delicate fabrics like silk or thin cotton, interfacing under both snap halves will help them last longer and prevent the fabric from tearing.
Frequently Asked Questions
Can I sew snaps on stretchy fabric like jersey or knit?
Yes, but reinforce the area first. Cut a small square of woven interfacing (about one inch by one inch) and fuse it to the underside of the fabric where the snap will go, following the interfacing package directions. This prevents the snap from pulling through the fabric when you press it closed. Sew the snap through both the fabric and the interfacing.
What if the snap keeps popping open?
The stitches may be loose, or the snap halves may not be aligned. Test by pressing them together by hand—if they do not catch firmly, resew at least one half with tighter stitches, going through each hole three times. If they catch by hand but pop open when worn, the snap may be too small for the weight of your fabric; try a larger size next time.
How many times should I stitch through each hole?
Two passes (eight stitches total) is standard and holds well for most garments. For heavy fabrics or items that get a lot of wear, three passes (twelve stitches) provides extra security. For delicate fabrics, two passes is usually enough if your stitches are tight and close together.
Can I sew snaps on a machine instead of by hand?
Most home sewing machines cannot sew snaps directly because the snap halves are too thick and the holes are too small. A few industrial machines have snap-setting attachments, but these are not common in home sewing. Hand-sewing is the standard method and takes only a few minutes per snap.
Do I need to use a snap-setting tool?
No. A snap-setting tool uses pressure to force the snap halves together, but hand-sewing is just as durable and gives you better control over placement. Tools are faster if you are sewing many snaps at once, but for one or two snaps on a garment, hand-sewing is simpler and does not require buying extra equipment.