The Short Answer
For most home sewing, a good-quality all-purpose polyester thread is a safe default. It has a little give, holds up to regular washing, and runs smoothly in most modern machines. Cotton is a popular choice for quilting and for natural-fiber projects, and specialty threads (embroidery, elastic, heavy-duty, metallic, monofilament) exist for jobs that all-purpose thread does not do well.
Choosing well comes down to three things: the fiber, the weight (thickness), and the finish. The sections below explain each one, then walk through common thread types by job.
Thread Fibers at a Glance
| Fiber | Typical strengths | Typical trade-offs |
|---|---|---|
| Polyester | Strong, some stretch, good colorfastness, widely available | Can look less matte than cotton; some very cheap spools are uneven |
| Cotton | Soft, matte look, pairs naturally with cotton fabric, popular for piecing and quilting | Less stretch, may produce more lint, usually less strong than polyester of the same weight |
| Cotton-wrapped polyester (corespun) | Polyester core for strength, cotton outer for look and feel | Not needed for every project |
| Nylon | Strong and flexible; common for monofilament (“invisible”) thread and some upholstery or outdoor uses | Sensitive to high heat; check the label for intended use |
| Silk | Fine, strong for its thickness, smooth and lustrous | Costs more; often saved for hand sewing, tailoring or fine hand applique |
| Rayon | High sheen, popular in machine embroidery | Often less durable than polyester; generally chosen for decoration |
Always check the label. Manufacturers vary in how they describe their threads, and the fiber content on the spool is the most reliable guide to how a thread will behave.
Understanding Thread Weight
Thread weight describes how thick the thread is. With the common “wt” system, a higher number means a finer thread. A 50 wt thread is thinner than a 40 wt thread, and a 12 wt thread is much thicker than either.
- Very fine (80-100 wt): nearly invisible stitching, used for fine hand applique, micro-quilting and delicate fabrics.
- Fine to medium (40-60 wt): the range for piecing, quilting and general construction.
- Heavier (30 wt and thicker): decorative topstitching, buttonholes and bold quilting.
Different brands label weight in different ways (wt, Tex, or a numbering system of their own), so comparing two brands by the number alone can mislead. When in doubt, compare the thread to one you already know works well in your machine.
Thread Words You Will See on the Spool
- Ply: the number of strands twisted together. More plies generally means a thicker, sometimes stronger thread.
- Corespun: a continuous-filament core wrapped in another fiber, combining strength with a particular look or feel. Common in thread sold for denim.
- Mercerized: cotton that has been treated to improve strength, luster and dye uptake.
- Gassed: cotton passed through a flame to burn off surface fuzz, giving a smoother, lower-lint thread.
- Twist (Z or S): the direction the strands are twisted. Most home-machine thread uses a Z twist, which is what most machines expect.
- Monofilament: a single clear or smoke-colored strand, similar in feel to fine fishing line.
Common Thread Types by Job
All-Purpose Thread
The workhorse for seams, hems and general repairs. Usually polyester or cotton-wrapped polyester. It is a reasonable choice for most fabrics from lightweight to medium weight, though very sheer or very heavy fabrics may do better with a finer or heavier thread.
Quilting Thread
Quilting thread is chosen mostly for appearance. Cotton is a common match for cotton quilts, and fine polyester or cotton-polyester blends are used when you want stitches to sink into the fabric. Hand quilting has its own thread options, and big-stitch hand quilting uses thicker perle cotton. If you work with fine hand applique, see our guide to the best thread for hand applique.
Embroidery Thread
Machine embroidery thread is usually rayon or polyester. Rayon is prized for sheen, while polyester is often chosen for durability and colorfastness. Hand embroidery floss is a different product, normally six loosely twisted strands that you separate to build the thickness you want.
Heavy-Duty and Upholstery Thread
Thicker, stronger thread for canvas, bags, outdoor gear and upholstery. Some versions are treated for UV or water resistance. Use a larger needle and test your machine’s tension on a scrap first.
Topstitching Thread
Thicker thread for decorative lines on jeans, bags and jackets. It generally needs a larger eye and a deeper groove than a standard needle provides. Our comparison of the topstitch needle vs universal needle shows how to pair them.
Elastic Thread
Used in the bobbin for shirring. It is usually wound by hand onto the bobbin with a light touch. Always test on a scrap, as results vary with fabric and machine.
Monofilament (Clear) Thread
Useful when you want stitching to disappear, such as for some quilting and decorative work. Many sewists use a lower speed and a thread net or stand, because it slips off the spool easily.
Metallic Thread
Decorative and more fragile than regular thread. A topstitch or specialty metallic needle with a larger eye is a common recommendation, and slower stitching usually helps.
Serger (Overlocker) Thread
Sold on large cones and typically finer than all-purpose spools, since several threads are used together in one stitch. Check your machine manual before using unusual threads.
Beading Thread
Beading projects have different demands from garment sewing. Strength, low stretch and resistance to sharp bead edges matter most. See our guide to using polyester thread for beading.
How to Tell Cotton From Polyester
If the label is missing, a few simple checks can give you a good guess. None of them is perfect, so treat the result as a hint.
- Look and feel. Cotton typically looks matte and a little fuzzy; polyester often looks smoother with a slight sheen.
- Pull test. Snap a short length. Polyester tends to stretch noticeably before it breaks, while cotton tends to break with less stretch.
- Burn test (with caution). Only do this over a non-flammable surface, away from anything flammable, with water nearby. Cotton usually burns like paper and leaves a soft gray ash; polyester usually melts and leaves a hard bead. If you are not comfortable doing this, skip it.
What Is the Strongest Thread?
There is no single answer, because strength depends on fiber, thickness, ply and construction. Generally:
- Within a given weight, polyester and nylon are commonly stronger than cotton or rayon.
- Thicker, multi-ply thread is stronger than thin thread of the same fiber.
- Specialty industrial threads, such as aramid fibers used in demanding applications, are stronger still but are not designed for typical home machines.
A very strong thread can sometimes cause the fabric to tear before the stitching fails, so on lighter or delicate fabrics the strongest thread is not always the better choice.
Match Thread, Needle and Fabric
A great thread can still perform poorly with the wrong needle. A general rule is to choose a needle whose eye is large enough for the thread to pass easily, but small enough not to leave large holes in the fabric.
- Fine threads pair with smaller needles.
- Thicker threads need larger needles and often a larger eye.
- Knits, denim and microfiber fabrics each have specialty needles.
If the thread frays, shreds or skips stitches, try a new needle first and then a different size or type.
Machine Thread vs Hand Sewing Thread
Many threads work for both, but some are made specifically for hand use. Hand-quilting thread, for example, is designed to resist tangling as it is pulled through layers. Machine thread is designed to run through guides, tension discs and needles at speed. When in doubt, follow the intended use on the spool.
Industrial machines have their own thread demands, including large cones, higher speeds and specific needle systems. If you are looking at heavier equipment, our guide to industrial sewing machine specifications covers what the numbers mean.
Common Thread Problems
- Thread keeps breaking: rethread the machine with the presser foot up, replace the needle, and check that the needle is large enough for the thread.
- Skipped stitches: often a bent or dull needle, or the wrong needle type for the fabric.
- Loops on the underside: commonly a threading or tension issue; rethread both the top thread and the bobbin.
- Lots of lint: may point to a lower-quality thread; clean the bobbin area regularly.
- Old thread snapping easily: thread can weaken over time, especially if stored in sunlight. Store spools away from direct light and heat.
Quick Buying Tips
- Start with a few neutral shades of all-purpose polyester.
- Match thread color to the fabric or choose a slightly darker shade, since thread often looks lighter when stitched.
- Test any new thread on a scrap of your actual fabric before starting.
- Stick with reputable brands for projects you care about, and compare them yourself rather than relying on price alone.
Frequently Asked Questions
What are the three basic types of thread? Many guides group them by fiber: natural (cotton, silk), synthetic (polyester, nylon, rayon) and blended or corespun. Others group by use: all-purpose, specialty and heavy-duty. Either grouping is reasonable.
Can I use hand-sewing thread in my machine? Some hand threads work, but those designed for hand use may be too stiff or too coated for machine use. Check the label and test on a scrap.
Do I need different thread for the bobbin? Many projects use the same thread top and bottom, but some techniques, like decorative stitching or shirring, use a different thread in the bobbin on purpose.