Sewing machine vs overlocker: which comes first?

What a sewing machine does

A domestic sewing machine forms a lockstitch: an upper thread from the needle interlocks with a bobbin thread underneath the fabric. That single stitch structure covers an enormous range of jobs. You can sew a straight seam, topstitch a collar, insert a zip, sew a buttonhole, attach a waistband, gather a skirt and run a blind hem, all on one machine by changing the stitch and the presser foot.

Most modern machines also offer a zigzag and one or more overcast stitches, which let you neaten raw edges so they do not fray. That is the job people most often buy an overlocker for, so a sewing machine already covers it, just more slowly and with a less professional look on the inside of the garment.

What an overlocker does

An overlocker uses loopers instead of a bobbin. On a typical 3 or 4 thread machine, one or two needle threads form the seam line while the upper and lower looper threads wrap around the cut edge. A pair of knives trims the seam allowance just ahead of the needles, so a single pass sews the seam, cuts off the excess and encloses the raw edge.

The resulting stitch stretches, which is why overlockers are so useful for jersey, sweatshirt fleece, swimwear and activewear. Many also have differential feed, which adjusts how fast the front and back feed dogs move so knits do not wave and fine fabrics do not pucker. Our differential feed explainer covers how to set it.

What an overlocker cannot do is just as important. It will not sew a buttonhole, insert a standard zip neatly, topstitch, sew a seam away from the fabric edge or sew a dart in the usual way, because it is always cutting and wrapping an edge.

Note:Switch off and unplug the machine before changing needles, opening the looper cover or cleaning out trimmings. For motor, wiring or timing faults, use a qualified sewing machine engineer rather than opening the machine yourself.

Side by side: Brother SH40 and Brother M343D

To make the difference concrete, here are two machines from the same maker: the Brother SH40, a computerised sewing machine, and the Brother M343D, a 3 or 4 thread overlocker. The table uses only details from the product listings; anything the listing does not give is marked as not stated.

See our beginner overlocker picks →

Which jobs need which machine

The quickest way to decide is to look at the projects you want to make. Woven dressmaking, home furnishings, bags, quilting and alterations are almost entirely sewing machine work. Knit tops, leggings, loungewear and swimwear benefit hugely from an overlocker, although even then you will usually hem, topstitch or add elastic with a sewing machine.

Which to buy first

For a beginner, the answer is nearly always a sewing machine. It lets you finish complete garments on its own, and its zigzag and overcast stitches cover edge neatening until you are ready for more. Our guide to the best sewing machines for beginners lists models with the stretch and overcast stitches that make knits manageable.

An overlocker makes sense as the second machine once you are sewing regularly, especially if you make a lot of knitwear or want a cleaner inside finish. It is also a good fit for someone who already owns a reliable sewing machine and finds edge finishing slow. Threading looks daunting at first, so read our overlocker threading guide and keep the manual close, as thread paths and colour coding differ between makers.

• Buy a sewing machine first if you are new to sewing, want to make woven garments, or need zips and buttonholes.
• Add an overlocker when you sew knits often or want shop style seam finishes.
• Consider both together only if you already know you will sew mainly stretch fabrics and have the space for two machines.

Space, learning curve and running costs in practice

Two machines need two spaces on the table, or a habit of swapping them over. Many sewists set the overlocker beside the sewing machine so they can sew a seam, then neaten it, without moving.

An overlocker uses three or four cones of thread at once rather than one spool and a bobbin, so you will want cones in your most used colours. Neutral greys, cream, black and navy blend into most fabrics. Knife blades and needles wear and need replacing from time to time; check your manual for the needle system your overlocker uses, as it can differ from a household sewing machine. Our needle size guide helps with the sewing machine side.

Frequently asked questions

Can an overlocker replace a sewing machine? No. An overlocker always trims and wraps an edge, so it cannot sew buttonholes, insert zips neatly, topstitch or sew anywhere away from the fabric edge. Most garments still need a sewing machine for those steps.

Is a serger the same as an overlocker? Yes. Serger is the usual American term and overlocker the usual British one. Both describe a machine with loopers and knives that sews, trims and finishes an edge in one pass.

Can a sewing machine sew stretch fabric without an overlocker? Yes. Use a ballpoint or stretch needle, a stretch stitch or narrow zigzag, and sew slowly without pulling the fabric. Our guide on how to sew stretch fabric walks through the settings.

Is an overlocker hard for a beginner? It is mostly the threading that takes practice. Once threaded, it is quick to use. Colour coded thread guides and easier lower looper threading, as on the Brother M343D, help, and tying new threads onto old ones is a common shortcut when changing colours.