Knitting Pin and Needle Sizes

Conversion Table

In the United Kingdom (U.K.) sizes used to be based upon the British Standard Wire Gauge (S.W.G.), which has origins in 1853 and later came to be called «B.S. 3737:1964».  This U.K. numbering system is easily confused with the United States (U.S.) numbering system because they are written similarly and not always with the designator U.K. or U.S. in front of the size.  In both systems numbers smaller than zero are written with multiple zeros; i.e., the number 000 is smaller than the number 00, which is smaller than the number 0.  These numbers can also be written in shorthand; i.e., 000 can be written 3/0.  Although larger numbers translate to larger sizes in the U.S. numbering system, larger numbers translate to smaller sizes in the U.K. numbering system; this leads to further confusion.

There are many conversion tables on-line and in books.  Many look the same because they are copies of each other, but an attentive eye will see minor differences.  Sometimes these differences were created because a hook, needle, or pin manufacturer used to produce tools of a particular metric size and later decided a different metric size ought to be marked with the same U.S. size.  More confusion is introduced when manufacturers and publishers use both imperial (U.K. or U.S.) and metric sizing because it is unclear which system was used when producing the item and which system was ascribed for «convenience.»  As one can see, it is not convenient at all since the consumer is left to guess.

My conversion table for knitting needle and pin sizes does not look much different from most others one might find; yet, this table is special because instead of guessing at what might be equivalent U.K. sizes based on other conversion tables, I calculated each of the S.W.G. metric sizes to the ten-thousandth of a millimeter, then rounded each S.W.G. to the metric size of knitting pins and needles currently in production and labeled it with the appropriate U.K. size.  For easy reference I also listed U.S. sizes established by C.Y.C.A., with the exception of Sizes 0 through 8/0, which are not defined by C.Y.C.A.  Common convention dictates U.S. sizes decrease in 0.25‑mm decrements from 2.25 mm (Size U.S. 1).

Other conversion tables I found do not provide any references to which one can determine proper preparation of those tables.  They state conversions as a matter of fact, and I presume the preparers of said tables are borrowing from other tables.  The problem perpetuates with each successive generation of tables.  For my first example, look at The Fiber Gypsy conversion table.  It labels U.S. sizes as «contemporary» and  «old».  «Contemporary» is a loose description and does not cite any source.  No U.S. size is defined by C.Y.C.A. to include more than one metric equivalent, and no size smaller than 2.25 mm is defined by C.Y.C.A.; so, the «contemporary» definition does not come from C.Y.C.A., which as a consortium of publishers and yarn, needle, and pin manufacturers is the nearest thing to a standards body for knitting pin and needle sizes in the U.S.   «Old» is cited from the reproduction of a Boye Needle gauge, but Boye Needle does not cite a source.  One will notice the steel sizes in this definition are quite similar to the stated U.K. sizes upon which they are based; but as they are not identical values, inexactness is perceived to have originated either from Boye Needle’s «old» definition or from the definition of the U.K. sizes in the table in question, where again no source is declared.  For my second example, look at the Bugknits conversion table.  I appreciate the author’s explanation that conversions of irregular sizes are provided merely for convenience, and it is apparent these sizes are specified to help one recognize relative to another in the same sizing scheme; however, this table declares Size U.S. 8/0 to be 0.50 mm, which is inconsistent with common convention, a problem introduced by referring to yet another conversion table, I presume.

One might ask what is the significance of my conversion table and why bother demonstrating the deficiencies of other conversion tables, but I submit to the reader there should be a definitive source of information.  I believe the common understanding of U.K. sizing was lost decades ago.  Ignorance of this problem has gone unnoticed for various understandable reasons, but facts would be available to the people who seek them; so, I present them here.  Is it useful to know that 0.25 mm is a Size U.K. 33?  Not really, since none of the patterns written at the time U.K. sizing was in use call for Size U.K. 33 needles; however, using exact conversion as defined in my table provides exact relative size differences (to one ten-thousandth of a millimeter).  My table defines every metric size knitting pin and needle known to me to be currently produced, provides exact U.K. sizes for those metric sizes, provides all U.S. sizes as defined by C.Y.C.A., and includes the common convention for numbering U.S. sizes smaller than Size U.S. 1.  For the three sizing schemes described, I assert the information is complete and correct to the best of my knowledge.

Having read the above material, hopefully the reader is persuaded of the importance in using metric sizing for writing publications and referencing tools.  It is for the convenience of translating old U.K. patterns and modern American patterns to the metric system that this table is provided.  Please encourage others to consult this table for its accuracy.

Recommended Hook, Needle, and Pin Sizes for Various Thread Weights

Thread weight:  Craft Yarn Council of America (C.Y.C.A.) does not publish standards for thread weights.  Heavy, medium, and light are generalized terms to describe common perceptions of thread weights.  Thread weight is usually described by a number.  The thread weight numbers in this chart are sizes marked on thread marketed as crochet thread.

Hook sizes:  C.Y.C.A. establishes U.S. sizes of hooks between 2.25 mm (Size U.S. B) and 19 mm (Size U.S. S).  With the exception of the statement «The smallest steel hook is a #14 or .9 mm; the largest is a 00 or 2.7 mm,» hook sizes smaller than 2.25 mm are not defined by C.Y.C.A.  Please note there are hooks smaller than 0.90 mm, but they are not acknowledged by C.Y.C.A.  Primm-Dritz manufactures each of the hook sizes in this chart and larger sizes as well.

1. Wrights, maker of Boye brand hooks, whilst a member of C.Y.C.A., contradicts the C.Y.C.A. definition of both Sizes U.S. 14 and 00:  Wrights considers 0.75 mm, not 0.9 mm, to be Size U.S. 14 and 3.5 mm, not 2.7 mm, to be Size U.S. 00.  Because of the inconsistencies even amongst members of C.Y.C.A., it is strongly recommended the metric size be referenced.  *Boye hook sizes are presented not as equivalents of the metric sizes in the chart but as suggestions to be used with the thread weights in the chart.
   

Needle and Pin sizes:  C.Y.C.A. establishes U.S. sizes of needles between 2.25 mm (Size U.S. 1) and 25 mm (Size U.S. 50).  Needle and pin sizes smaller than 2.25 mm are not defined by C.Y.C.A.  Common convention dictates U.S. sizes decrease in 0.25‑mm decrements from 2.25 mm (Size U.S. 1).  Primm-Dritz manufactures each of the needle and pin sizes 1.25 mm and larger in this chart.  It is strongly recommended the metric size be referenced.

INOX Needles and Pins

INOX is my favorite brand of knitting needles and pins.  The quality is excellent, and the variety of gauges and lengths surpasses all other manufacturers:  Eight gauges are available in steel, half in two lengths; there are 16 gauges of circulars available in up to 11 lengths; and all measurements are given in metric.  Most other brands offer no steel, fewer gauges of circulars, fewer lengths, and are in disagreement about standard gauges.  To me the choice is clear:  If you want a broad range of consistent gauges and lengths, buy INOX.

1. Caveat emptor:  William Prym GmbH & Co.  KG is the holding company of Prym Consumer Group, which has two divisions:  Prym Consumer Europe and Prym Consumer USA.  Prym Consumer Europe informed me there is no U.S. distributor for its INOX brand, contrary to some on-line sources; and Prym Consumer USA does not acknowledge INOX as an available brand in its sales region of North America and South America.  In America there are very few on-line sources of INOX, and these sources list imperial sizes not on the original packaging.  As Prym does not market its knitting products to Americans, there is no purpose for printing supposed U.S. sizes.  Let this be a warning to beware of imitations and use extreme caution if you purchase INOX or Prym brand needles, pins, and knitting accessories from sources outside Europe because you may be purchasing a knockoff.  Even reputable retailers are often unaware they sell knockoffs.  A big hint pointing to an INOX knockoff is a U.S. size on packaging.
   

I flew to Munich, Germany, to buy some knitting needles.  First I asked some Americans who fly regularly to Munich where I could find a craft store to buy knitting tools.  I was directed to what is labeled a «craft» store, but the store I visited was actually a painted-art supply.

Next I enquired of a concierge the location of a yarn store, and I was directed to Ludwig Beck in the Marienplatz.  (Ludwig Beck is the name of the man who opened the Ludwig Beck store in 1861.  Renamed from Schrannenplatz 1854, Marienplatz dates back to 1310.)  Even with a map I got lost and had to ask for help several times to find the Marienplatz.  After a long time I found Ludwig Beck, which is a clothing store.  Fortunately a woman there at the information desk eventually understood I was not in the market for clothes, and once again I had to try to explain knitting and yarn.  Gestures came in handy.

As it turns out, Ludwig Beck expanded in 2001 to include a yarn and thread shop named Geknöpft & Zugenäht!, which is nearby.  Here I found INOX packaging with the Prym brand.  The store has quite a few sizes but no steel needles or pins.  The women who work in the store assured me that if their store does not have what I need, it is nowhere to be found in Munich; and, no, they would not place a special order for me.  This is not what I wanted to hear after traveling thousands of miles, and it is certainly not something I expected to hear in the third largest city in Germany.  I also went to Frankfurt but found no INOX at all.  I am sure some merchant sells it somewhere, but I had a hard time communicating.

My needle set is made up of INOX needles supplied by Geknöpft & Zugenäht! in Munich and also Heirloom Knitting in the U.K.  Some sizes I am still finding difficult to locate, and I just borrow some Knit Picks Harmony needles as I need them.  I discovered it is easier to find whole- and half-millimeter sizes in Europe and quarter- and three-quarters-millimeter sizes in America, but I have not located in America INOX needles that are not knockoffs.