A T-shirt neckband lies flat when it is shorter than the neckline it goes on: cut it to 80–85 % of the neckline measurement, join it into a loop, fold it in half, divide both the band and the neckline into quarters, and sew with the band on top, stretching only the band between the pins. Use a stretch stitch or a narrow zigzag, a 1 cm (3/8 in) seam allowance, press the seam toward the body and topstitch. A band that is cut too long waves; one cut too short pulls the neckline in; the ratio depends on how stretchy your band fabric is.
Why does a neckband need to be shorter than the neckline?
The neckline of a T-shirt is a curve, and the band sits inside it, on a smaller circle. If the band were the same length as the neckline, it would have nothing to do but flop outward, with the fabric waving along the edge. Cut shorter and stretched to fit, the band pulls the neckline into a slight cup against the body and lies flat. This is the same negative ease that makes a T-shirt fit a body smaller than the fabric would measure.
How much shorter depends on two things: the stretch of the band fabric and the depth of the neckline. A stretchy rib and a deep scoop take a shorter band; a stable jersey and a high crew neck take a longer one.
What do you need to sew a neckband?
- The T-shirt body with the shoulder seams sewn.
- Band fabric: rib knit 1×1 or 2×2, or the same jersey as the body if it has at least 50 % stretch across the grain. Check with how to measure stretch percentage.
- A ballpoint or stretch needle, 75/11 or 80/12, and polyester thread.
- A stretch stitch (the lightning bolt), a narrow zigzag 1 mm wide and 2.5 mm long, or a serger with a 4-thread overlock.
- A twin needle 4 mm (or a coverstitch machine) for the topstitching, optional.
- A tape measure, four pins or clips, and a press cloth.
Cut the band across the grain, in the direction of greatest stretch, and if the rib has a right side, mark it with a pin.
How long should the neckband be?
Measure the neckline on the sewn body along the stitching line, 1 cm from the raw edge, with the tape standing on its edge around the curve. Then multiply:
| Band fabric and neckline | Band length as % of neckline |
|---|---|
| Rib knit, crew neck | 80 % |
| Rib knit, scoop or V | 75–80 % |
| Jersey with 50 % or more stretch, crew neck | 85 % |
| Jersey with 50 % or more stretch, scoop | 80–85 % |
| Stable interlock or French terry | 90 %, with a wider band |
Add 2 cm (3/4 in) for the seam that closes the loop. For a 48 cm (19 in) crew neckline in rib, cut the band 48 × 0.8 + 2 = 40.4 cm (15 7/8 in) long. The width is twice the finished band plus two seam allowances: for a 2 cm (3/4 in) finished band with 1 cm allowances, cut 6 cm (2 3/8 in). A wider band, 2.5–3 cm finished, suits a sweatshirt; a narrower one, 1.5 cm, a fitted tee.
Tip: Before you cut, wrap the band fabric around the neckline, stretched as you would sew it, and see whether the stretched band lies flat against the curve without pulling it in. Each fabric has its own ratio, and this test takes a minute.
How do you sew the neckband, step by step?
- Join the loop. Fold the band in half crosswise, right sides together, and sew the short ends with a 1 cm (3/8 in) seam. Press the seam open, or to one side if you overlocked it, then trim its allowance to 5 mm so it does not show as a bump.
- Fold the band in half lengthwise, wrong sides together, raw edges level, and press lightly with steam. Do not stretch it while pressing.
- Quarter the band. Mark the seam with a pin, then fold the loop so the seam is at one end and mark the opposite fold; fold again to find the two side quarters. Do the same on the neckline, with the center back and center front as two of the marks. The quarters of the neckline are not at the shoulder seams; the front neckline is longer than the back, so the side marks fall slightly forward of the shoulders.
- Pin the band to the neckline, right sides together, raw edges level, matching the four marks. Put the band's seam at the center back or at the left shoulder, where the stripe of a rib hides it best. Between the pins the band is shorter than the neckline; it will be stretched to fit.
- Sew with the band on top. Starting at the center back, with a stretch stitch or narrow zigzag at 1 cm from the edge, stretch the band between the first two pins until it matches the neckline, keep the body flat and unstretched, and sew. Release, move to the next quarter and repeat. Sewing on a serger is the same: hold the band taut in front of the foot, never pull the body.
- Check before pressing: lay the T-shirt flat. The neckline should be a smooth curve with the band lying flat inside it, no waves and no pulling. If it waves, the band is too long for the fabric; unpick it and shorten by 2 cm. If the neckline pulls in or the body wrinkles around it, lengthen by 2 cm.
- Press the seam allowances toward the body, from the wrong side, with steam and a press cloth; lower the iron and lift it, do not slide, so the band keeps its shape. Go around once more from the right side with the band rolled slightly to the inside.
- Topstitch 5 mm (3/16 in) below the seam on the body, through the allowances, with a 4 mm twin needle, a coverstitch or a narrow zigzag. This holds the allowances down, stops the band from rolling out, and is what makes the neckline look bought. The twin needle, coverstitch or zigzag comparison explains the settings for each.
The sewing knit fabrics guide covers the stitches and needles if your machine is a regular one.
Common mistakes with T-shirt neckbands
- Band too long. The most common reason a neckline waves. Use the ratio and test on the fabric; rib is more forgiving than jersey, jersey more than interlock.
- Stretching the body while sewing. The neckline grows and the band cannot pull it back. Only the band stretches; the body feeds flat.
- Quartering at the shoulder seams. The front neckline is longer than the back, so the side quarters sit forward of the shoulders. Fold the neckline to find the true quarters.
- A straight stitch. It snaps when the neck goes over the head. Use a stretch stitch, a zigzag or an overlock.
- Skipping the press after sewing. The band looks bubbly until the seam has been steamed and the allowances pressed toward the body.
- Topstitching with a straight stitch and a universal needle. It pops and skips. Use a twin needle with a ballpoint tip, a slightly loosened upper tension, and a 3 mm stitch length.
- Cutting the band along the grain instead of across it, so it has no stretch and tears the neckline.
When should you use a neckband instead of a facing or binding?
A folded neckband is the standard finish on T-shirts, sweatshirts and tanks in knit fabric: it stretches over the head, recovers, and needs no interfacing. Use a knit binding (a single-layer strip wrapped around the raw edge) when you want a narrower, flatter edge on a tank top or a lightweight jersey, and a facing on a knit only for a very wide boat neck in a stable fabric, where a band would stand away. On a woven fabric, a neckband does not work at all: a woven neckline takes a facing or bias binding.
Sewly's T-shirt pattern uses a 1 cm (3/8 in) seam allowance on knits by default and cuts the neckband at 85 % of the neckline, with that length given in the sewing guide; you can ask the guide which ratio to use for a rib you have measured. For a first T-shirt from any pattern, sew your first T-shirt walks through the whole garment in order, with the neckband going on before the sleeves.