The WORSTED SYSTEM(wools,acrylics, and some others) is based on 560 yds per lb. of one strand of a #1 size. it is written 1/1. The first # is the ply, the second # is the count(size of each ply). This means a 1/1 = 560 yds per lb.

A 1/2 yarn is 1 ply of #2 size yarn. 2 X 560 yds/lb = 1120 yds/lb What this means is a #2 size yarn is 1/2 as thick & twice as long as a 1/1 yarn

A 1/3 yarn is 1 ply of #3 size yarn. 3 X 560 yds/lb = 1680 yds/lb What this means is a #3 size yarn is 1/3 as thick & 3 times as long as a 1/1 yarn


For multiple plies, the First # is ALWAYS the number of plies, and the second number refers to the size of each ply. To get the yards per pound, divide the first number into the second number and multiply by 560 yds/lb.
For example:
2/24 = 1/12 ; 12 X 560yds/lb = 6720 yds/lb
2/28 = 1/14; 14 X 560 yds/lb= 7840 yds/lb
3/15= 1/5; 5 X 560yds/lb= 2800 yds/ lb

If you are using multiple strands of a thin yarn, divide the yds/lb by the number of strands you are using.
For example:
2 strands of 2/24 = 3360 yds/lb.

COTTON YARNS(and various blends) use the COTTON SYSTEM which is based on 840 yds/lb. Here, the ply count is the REVERSE of the WORSTED SYSTEM in that the first # is the the size & the second # is the number of plies.

Here you divide the second digit into the first and multiply by 840 yds/lb.
For example:
16/2 = 8/1; 8 X 840yds/lb = 6720 yds/lb
20/2 = 1/10; 10 X 840 yds/lb = 8400 yds/lb

When using multiple strands, once again, divide the yds/lb by the number of strands you are using.
For example:
2 strands of 16/2; 6720 divided by 2 = 3360 yds/lb.

When substituting yarns, a rule of thumb is that if the yardage of the yarn you want to substitute is within 10% of the yardage of the yarn called for, you can substitute, making adjustments in tension(needle size for hand-knitters). Always make a swatch when substituting yarns! This rule of thumb ONLY applies to similar yarns of the same system, NOT substituting cotton for wool or acrylic. Remember, a hard finish dress yarn will behave and knit differently from a high bulk acrylic.

In substituting handknitting yarn for machine knitting yarn & vice-versa, here are some names and numbers:
3/11 = Sport Weight
4/8 = Worsted Weight
2/11; 3/15 = Fingering Weight
2/20; 2/24 = Fine weight
2 strands of 2/24 = Fingering Weight.

To get yards per pound from hand knitting yarn, you need to do a little math.

For example:
You have a 50gm ball of Sport Weight yarn with 184 yds.
First, there are approx. 28gm/oz or 454gm/lb.
184yds divided by 50gm gives you 3.68 yds per gram X 454gms/lb = 1671yds/lb

If the skein or ball is marked in ounces, a 50 gm ball = approx 1.75 oz.
Using the example above, 184 divided by 1.75 = 105.14 yds/oz X 16oz
=1682yds/lb. The approximate yardage for this yarn is about 1675yds/lb

If the yardage is given in meters, remember that a meter is approximately 39 inches. The yardage in meters on the label of my example yarn is given at 168 meters. 168 X 39 in/M =6552 inches divided by 36 in/yd = 182yds (very close to the stated yardage on the package, 184)
The system for linen is based up a lea, which is 300 yards, making 300 the key number for the linen formula. For example a 4/1 linen would have 1200 yards per pound.