Sewing Needle Size Calculator
Machine needle size from fabric weight.
Find the right sewing machine needle size for a fabric weight in GSM, with the metric and Singer numbers and what each suits.
Use the GSM converter if your fabric is quoted in ounces per square yard.
Needle size
80/12
Quilting cotton, poplin, light jersey
Use the lightest needle that carries the thread through without deflecting — an oversized needle leaves visible holes that never close on fine fabric. Needle type matters as much as size: ballpoint for knits, microtex for tightly woven. Change it every eight to ten hours of sewing; a blunt needle causes skipped stitches long before it looks blunt.
How the Sewing Needle Size Calculator works
Needle sizes are given as a pair — 80/12 is the metric and Singer number for the same 0.8 mm needle — and the rule is the lightest needle that will carry the thread through the fabric without deflecting. Going bigger to be safe leaves visible holes, and on fine fabric those never close up.
Also known as: machine needle size chart · sewing needle chart
The lightest needle that works
Needle sizes come as a pair — 80/12 is the metric and Singer designation for the same needle, 0.8 mm across. The metric number is the diameter in hundredths of a millimetre, which makes it the more informative of the two.
The rule is to use the lightest needle that will carry the thread through the fabric without deflecting. Deflection causes skipped stitches; an oversized needle causes visible holes, and on fine or tightly woven fabric those never close up.
Weight is the main guide — 60/8 for chiffon, 80/12 for quilting cotton, 100/16 for denim — but it is a guide rather than a rule, because weave density matters as much as weight.
A worked example
A 140 gsm quilting cotton takes an 80/12, the most common domestic size and the one most machines ship with. A 320 gsm denim takes a 100/16, and using the 80 on it will deflect and skip.
Going the other way is worse. An 80/12 through 70 gsm silk leaves holes that show, and dropping to a 60/8 with a fine thread is the difference between a garment that looks finished and one that looks punctured.
Where the answer misleads
Type matters as much as size and the number says nothing about it. A ballpoint or stretch needle pushes between knit loops rather than piercing them, preventing the laddering that a sharp causes; a microtex gives cleaner stitching on densely woven fabric. Size and type are independent choices.
Thread thickness also constrains the needle: the eye has to carry the thread without fraying it. A heavy topstitching thread needs a larger needle than the fabric alone would suggest, which is the one case where sizing up is right.
Finally, needles blunt long before they look blunt. Eight to ten hours of sewing is the usual replacement interval, and a fresh needle is the cheapest fix for most stitch quality problems — worth trying before adjusting tension.
Frequently asked questions
What needle size should I use?
Match it to the fabric weight: 60/8 to 70/10 for chiffon and lawn, 80/12 for quilting cotton and poplin, 90/14 for linen and light denim, 100/16 for denim and canvas.
What do the two numbers mean?
The metric number is the needle's diameter in hundredths of a millimetre, so 80 is 0.8 mm. The second is the American Singer size for the same needle. They are two names for one thing.
Does the needle type matter as much as the size?
Often more. A ballpoint or stretch needle pushes between knit loops instead of piercing them, and a sharp or microtex gives cleaner stitching on tightly woven fabric. Size and type are separate choices.
How often should I change the needle?
Every eight to ten hours of sewing, or at the start of any significant project. A blunt needle causes skipped stitches, snagging and puckering long before it looks blunt, and it is the cheapest fix for most stitch problems.