Nylon Thread Information

Nylon Thread Information

Our Nylon Thread Information page talks about this thread from the customers' viewpoint. Customers learn about when nylon thread should and should not be used, picking the right thread size (thickness), the difference between bonded and soft finishes, deciding how much thread is needed, nylon's elongation (stretchiness), and the difference between left and right twist thread. There are specifications for eleven nylon thread sizes at the bottom of the page and a new Nylon Thread Size Guide.

When to use nylon thread - Use nylon thread for applications that require a strong, inexpensive thread with a glossy smooth finish. This is why nylon is frequently used for upholstery, leather, webbing, canvas, and vinyl. Lighter weight (sizes 15 to 69) are used for garments that have glossy finishes. Nylon thread is not recommended for:

Outdoor applications with prolonged sunlight exposure. For example, nylon thread is a great choice for sewing indoor upholstery, and canvas drop cloths used by house painters. In should not be used for outdoor furniture and sewing canvas sails, awnings, tarpaulins. In these cases polyester thread or UVR rated nylon thread are better choices

Fire retardant garments and gear - Nylon thread yellows at 300 F, sticks at 445 F and melts at 500 F. First responder garments and gear and some high temperature conveyer belts require much more fire retardance. Use Fire Retardant Sewing Thread, Fire Retardant Embroidery Thread, Filament Kevlar Thread, and Filament Nomex Thread in these situations. All are heat resistant to 700°F or more.

Critical strength requirements - Nylon is strong but Filament Kevlar Thread is about twice as strong. For example, size 92 nylon has a 15 pound tensile strength; the same size Kevlar has a 30 pound tensile strength. Kevlar's downside is that it costs about five times more than nylon and only available in yellow. Consider using heavier weight nylon or double-stitching to meet strength requirements.

Cotton-like look - Our nylon thread has a smooth, glossy, shiny finish that does not go well with garments that need a soft, fuzzy, cotton-like look. Cotton, spun polyester and nylon thread, and fuzzy nylon are better and less expensive choices. We do not sell these products

Thread Sizes - A thread's size (or weight) refers to its thickness. We use U.S. commercial sizes on our site and cross-reference equivalent Tex and Government sizes. Here is an easy way to understand what happens as thread sizes increase:

When thread size increases...

When thread size increases...

Thread diameter


Stitch visibility




Sewing machine size


Sewing heat and friction


Yards per pound


Needle size




The material sewn often costs ten times more than the thread used to sew it. So, usually (parachutes excepted) the thread will break before the fabric tears. This means that the thickness and strength of the material sewn drives the thickness of the thread used. Here are two guides that relate material weight (ounces per square yard) to thread thickness

Fabric Weight / Thread Sizes from American & Efird

 Fabric Ounces per Square Yard

Thread Size Range

2 to 4 Oz

15 to 23

4 to 6 Oz

23 to 33

6 to 8 Oz

33 to 46

8 to 10 Oz

46 to 69

10 to 12 Oz

69 to 92

12 to 14 Oz

92 to 160

Springfield Leather

Leather Ounces per Square Yard

Thread Size Range

8 Oz or Less

69 to 207

8 Oz to 12 Oz

138 to 277

12 Oz to 16 Oz

207 to 346

Multiple layers

207 to 346

These guides make it clear that there there is a range of thread sizes that will work with different material weights. Also, sewing machine limitations may make double-stitching a lighter thread necessary and getting that "look" may justify using a heavier thread. Our Nylon Thread Size Guide gives size range recommendations for about 40 items. It is also available as a PDF Download

Bonded or soft? - Bonded means that a thread has a coating that reduces needle heat and fraying. It makes thread stiffer and about 5% thicker than soft thread. The choice between bonded and soft depends on how the thread is going to be used and thread thickness. Here are our recommendations:

Sewing Application


Machine sewing lightweight thread sizes 15 to 46

Lightweight thread sizes generate little needle heat and are unlikely to fray. Bonded and soft thread work equally well.

Machine sewing thread sizes 69 and higher

Bonded thread is strongly recommended

Hand sewing

It does not matter if you use bonded or soft thread.

Wrapping and gluing

Soft thread is preferred because bonded thread often repels glues and adhesives. You can soak a bonded thread in alcohol to remove the bonding

Other non-sewing applications such as hanging and reinforcing

Finish does not matter in most cases. Bonded thread is better if it is going through a narrow tube.

How much thread?  - We sell most of our nylon thread in 2 Ounce, 4 Ounce, and 16 Ounce (1 Pound) spool sizes or putups. The smaller putups cost more per ounce than the larger ones. However, they are better priced for casual sewers with one-time projects.

Nylon thread is sold by weight (ounces, pounds) - not yards. This is because the number of yards-per-pound decreases as thread thickness increases. Selling by weight means prices for a given size spool are about the same across most thread sizes.

Industry norms allow nylon thread spool weights to vary by ±10% from the stated nominal weight. This means that customers get slightly less or slightly more thread than the nominal weight shown on our site. The table on the right shows our nominal weights and the thread-weight range ( including the spool's weight ) for various sizes.  When spools fall within these ranges we do not charge for overages or refund underages.

Nominal Weight

Weight Range
Minimum Maximum

2 Oz

2.6 Oz

4.5 Oz

4 Oz

4.6 Oz

5.9 Oz

6 Oz

6.0 Oz

7.9 Oz

8 Oz

8.0 Oz

10.5 Oz

12 Oz

10.6 Oz

15.5 Oz

16 Oz

15.6 Oz

19.9 Oz

Spool Weight Dimensions
Base Height
2 Oz 2.5" 4.5"
4 Oz 2.5" 4.5"
8 Oz 3.5" 5.5"
16 Oz 4.5" 7.5"

The table on the right gives typical spool dimensions for nylon thread putups. Some home sewing machines do not have spindles that can handle our spools. Use a Thread Cone Holder to solve this problem. It bypasses the spindle feeds the thread directly into the machine as shown on the far right.

Elongation - Nylon thread stretches about 25% before it breaks. This means that 10 yards of nylon thread will be 12.5 yards when it snaps. This stretchiness is a good thing in most cases. It allows the seams to expand and contract with the material and avoids puckering and breakage. Nylon's stretchiness may not be desirable in some hanging, reinforcing, or wrapping applications. When this is so, consider less stretchy threads such as cotton, spun polyester, or Kevlar.

Twist - Most of the nylon thread on our site is left twist (also called Z-twist) because that is what single-needle machines made for the U.S. use. We have a few, clearly marked, right twist (also called S-twist) thread for double-needle machines. A thread's twist makes no difference when it comes to hand-sewing and non-sewing applications.

Other kinds of nylon - There are other kinds of nylon thread worth considering:

Monocord Nylon and Polyester - This thread is made by extruding hair-thin filaments into a smooth, one-ply thread with no twist that is slightly flat and ribbon-like. This thread runs smoother, reduces needle wear, and makes seams that are stronger and less conspicuous. Because it is one-ply, monocord can be used with double-needle machines. Most of our monocord has a UVR coating that gives it UV resistance equivalent to polyester thread.

Monofilament Thread - This thread is a true single-filament thread that is round, smooth, and semi-translucent. It blends with fabric and is the first choice for "invisible" seams. Use clear monofilament with light fabrics and smoke with dark fabrics.

Nylon Thread Specifications




Size 33


15 30 45 70 90 135 210 270 350 410 600


A AA B E F FF 3-Cord 4-Cord 5-Cord 6-Cord 8-Cord




2.0 5.0 8.0 11.0 15.0 22.0 32.0 45.0 53.0 73.0 83.0


0.9 2.3 3.6 5.0 6.8 10.0 14.5 20.4 24.0 32.7 37.8



Inches - decimal

0.0059 0.0080 0.0094 0.0116 0.1333 0.0163 0.0200 0.0231 0.0258 0.0283 0.0408

Inches - thousandths

6/1000 8/1000 9/1000 12/1000 13/1000 16/1000 20/1000 23/1000 26/1000 28/1000 40/1000


0.1010 0.2032 0.2388 0.2921 0.3378 0.4140 0.5080 0.5867 0.6563 0.7188 1.0358

Needle Size



10-12 12-14 14-16 16-18 18-20 20-22 22-24 24-26 26-28 28-30 30-32


70-80 80-90 90-100 100-110 110-120 120-14- 140-180 180-220 220-260 260-330 300-360

Nominal Yards


2 Ounce Spool

3,500 1,700 1,250 750 525 375 250 187 150 130 82

4 Ounce Spool

7,000 3,400 2,500 1,500 1.050 750 500 375 300 260 163

8 Ounce Spool

14,000 6,900 5,000 3,000 2,100 1,500 1,000 750 600 525 325

12 Ounce Spool

21,000 10,350 7,500 4,500 3,150 2,250 1,500 1,050 900 760 470

16 Ounce Spool

28,000 13,800 10,000 6,000 4,200 3,000 2,000 1,500 1,200 1,050 650

Type of Sewing Machine






Heavy Duty


Stitch Visibility






Stands Out


Focal Point



Small Spools

2 and 4 Ounce spools for small jobs.

Thread Sock

For Storage. Also helps prevent puddling.

Thread Boxes

Mixed nylon and poly in 5, 10, and 50 LB boxes.

Monocord Nylon

Single ply, flat, stronger, low profile stitching

Related Products

Polyester Thread

Looks, feels, sews like nylon. Better Sunlight (UV) resistance.

Half-Price Bobbins

Styles A/15, G, L, M at $20 a gross. About 100 selections

100 Yard Nylon Tube

Popular nylon sizes and colors on hand sewing tubes. Just $4.50

100 Yard Poly Tubes

Popular polyester sizes and colors on hand sewing tubes. Just $4.50

Waxed Thread

Large color selection in Sizes 207 through 554

Poly-Linen Blend

Silky-smooth Irish polyester-linen blend.

The Thread Exchange 291A Merrimon Ave Weaverville, NC 28787 - 800-915-2320