Felting Needle Sizes: A Gauge Chart, and What Each One Is For

Felting needle sizes are written as a gauge number, and the scale runs the wrong way round from every other measurement in craft: the bigger the number, the thinner the needle. A 40 is finer than a 36. That single inversion causes most of the confusion, and once it clicks, the rest of the chart is straightforward.

This page is the reference table. If you want the reasoning behind the barbs and blade shapes rather than the numbers, felting needles explained is the longer read.

The chart

Gauge	Feel	What it is for	Mark it leaves
32	Very coarse	Rugs, carpet wool, heavy joins	Obvious holes
36	Coarse	Cores, bulk, the first half of any shape	Visible pitting
38	Medium — all-purpose	Shaping, most of the work, general use	Closes up as you go
40	Fine	Surface, firming, tidying stray fibre	Almost none
42	Very fine	Faces, fur direction, thin colour	None visible
46	Finest	Miniatures, single wisps of fibre	None; snaps easily

If you take one thing from the table: coarse for inside, fine for outside. Every other decision follows from that.

36 gauge felting needles

The workhorse of the early stage. A 36 moves more fibre per stroke than anything else you will use by hand, which is exactly what you want when a handful of loose wool has to become a firm core and nothing about it looks like an object yet.

Its cost is the surface. The barbs are large enough to leave craters, and those craters do not disappear later — you cover them. So a 36 belongs under whatever anyone will look at. Pair it with cheap undyed fibre and the stage goes quickly: see core wool.

38 gauge felting needles

If the site could recommend only one gauge, this is it. A 38 builds shape at a reasonable speed and leaves marks that close up as you keep working, which means you can take a piece from loose wool to nearly finished without changing needles.

Most kits ship a 38 as their default for this reason, and most people find that two-thirds of their working time is spent on one. Beginners should start here rather than with a 36 — the slightly slower progress is repaid by not having to repair the surface. The rest of the starting kit is in felting needle kits.

38 gauge star needles

A star needle is four-sided rather than three, so it carries an extra row of barbs and moves proportionally more fibre. A 38 star behaves roughly like a fast 38: quicker through bulk, slightly less controlled, and blunter sooner because more edges are doing work.

Worth owning if you make larger pieces. Not worth owning as your only 38, because the extra bite is a nuisance on anything small.

40 gauge felting needles

The finishing gauge. A 40 firms a surface that is already dense, tucks stray fibre ends back in, and lets you add a thin layer of colour without dragging the layer underneath into it.

It is also the gauge to reach for when a piece has gone hard and a 38 has stopped biting. That is not a sign to push harder — it is a sign to go finer. Pushing harder is how needles break, which is covered in how to stop breaking felting needles.

42 gauge felting needles

Detail only. Eye sockets, the direction of fur, a whisker of colour on a cheek — work where the mark left by a 40 would still be too much. A 42 is noticeably more fragile, and it will snap if you angle it while it is buried.

You do not need one to start. You will want one the first time you try a face or an animal's coat: needle felting eyes and needle felting fur both live at this gauge.

Why there are no millimetre figures here

Because they would be made up. Felting needle gauge descends from an industrial wire scale, but manufacturers do not publish diameters for craft needles, and a "38" from one maker does not reliably match a "38" from another — the difference is small, real, and impossible to standardise from the outside.

Any chart quoting exact millimetres for every gauge is reporting one brand's numbers as if they were universal. Gauge is best used the way knitters use needle sizes in practice: as a relative scale you calibrate by feel, judging by the mark the needle leaves in your wool rather than by a specification.

Colour codes are not a standard either

Many sellers dip the crank in coloured paint so you can sort gauges at a glance, and it is a genuinely useful idea — especially in a kit, where a beginner cannot yet tell a 38 from a 40 by eye.

But the colours are chosen by each seller, not by an industry. Red does not mean 38 everywhere. Keep the packaging, or keep gauges in separate tubes, because once they are loose in a drawer the only way to tell them apart is to felt with them.

Which sizes to actually own

• Starting out: three 38s. That is genuinely enough for a first few projects.
• Once you are making shapes: add 36 for cores and 40 for surfaces — the standard working trio.
• Once you are making faces or animals: add a 42, and a reverse needle for raising fur.
• Rugs, bags or carpet wool: add a 32, and expect it to be the only gauge that copes.

Buy multiples of each rather than one of many. Needles are consumable — they blunt long before they break, and a blunt needle feels like a technique problem until you swap it.

Gauge is not the only number on the packet

Three things get confused with each other:

• Gauge — thickness. What this page is about.
• Shape — the cross-section: triangle, star, spiral, reverse, crown. It changes how much fibre moves per stroke as much as a gauge step does.
• Length — mostly comfort, and whether the needle fits a multi-needle tool. See needle felting pens.

A 38 triangle and a 38 star are not interchangeable, which is why two needles of the same stated size can feel quite different.

Matching gauge to wool

Coarse wool takes a coarse needle; fine wool does not. Merino is fine enough that a 36 tears rather than compacts it, so surface work in merino wants a 40 — see merino wool for felting. Coarser breeds and carding blends take a 36 happily and felt faster for it, which is covered in best wool for felting.

If a needle seems to be doing nothing at all, check the wool before the needle: superwash fibre has had its scales stripped and will not felt at any gauge. Why won't my wool felt goes through the rest of the causes, and needle felting for beginners covers the handling that makes any of these sizes work.