Why do patterns use gram rather than yards/meters

[cacunn]

I assume that this has bee asked before but my search has not come up with a answer therefore I will ask it.

Why do some patterns give the amount of yarn needed in grams rather that yards/meters?

While searching I found this appropriate statement by Knitasha:

Grams are a measure of weight.
Yards are a measure of length.
Apples and oranges.

If the pattern is using a yarn the for the number of Wraps-Per-Inch (WPI) does not weight much 50 grams of yarn may have 300 yards of yarn. A second ball of yarn with the same WPI but comes from a variety of sheep that has heavier wool may only have 250 yards for 50 grams.

Doesn't a pattern that calls for 50 grams of "X" yarn do a disservice to a knitter you may not like "X" yarn and wants to use another type? Especially, for a new knitter that does not have a lot of money or experience substituting yarns.

[newamy]

It's another way of estimating amount. I find yarn weight useful in the following instance: I used some stash to knit a mitten. When I'm done I don't know if I have enough for a second mitten. So I weigh the first one and my remaining yarn to see if there is enough.

[suzeeq]

Older patterns used to specify a certain yarn and tell you to use X skeins of it. It's much better when they tell you it's a certain yarn that comes in 50gm balls at xx yds/meters and to use X balls of it. But I haven't seen any recent patterns that only mention weight, just Elizabeth Zimmerman's and those came out in the 70s. If it's for a particular yarn, you can look up to see how many yds 50 or 100 gms has. Or maybe the pattern used handspun and the designer didn't know how long it was.

[Jan in CA]

I prefer yardage as well so fortunately most yarns/patterns give both.

[Marria]

The only modern patterns that I've seen which give weight instead of yardage are the ones in this book:

World of Knitted Toys

The patterns are adorable, but I haven't made any yet because I've been too lazy to try to estimate the yardage. But like Jan said, the vast majority of modern patterns have the yardage too.

[Plantgoddess+]

I look at the yardage per 50 grams and it gives me a rough idea of the weight of the yarn ie; fingering, dk, worsted, bulky etc. I then have an idea of what weight of yarn to look for in a substitute.

[Marria]

You also want to look at what fiber it calls for, because some different types of fiber have different weights. That's another thing that drives me crazy about the book I mentioned--for the most part it doesn't even mention what type of yarn to use. Still, I couldn't resist the book because the patterns are too cute for words.

[Lucy78green]

Most patterns in the UK/Ireland until recently only gave weight, probably because they are also assuming you are buying their recommended yarn.
My mum's rule of thumb she was taught was it takes one pound of yarn to made an adult jumper (sweater) but I suppose that depends on how big the person is too! I think yardage has only recently appeared on patterns here.
I have tried using some of my mum's older patterns that just says use X amount of balls of Y brand yarn without telling you if it's 4-ply, double knit etc so I made a jumper for a baby with DK and it should have been 4 ply so of course it was too big, but I figured he'd grow into it eventually!

[sylvia]

ok so why does the yarn i want to buy is always in yds
yds mean nothing to me i need to know how many grams
i gues all of us use different ways to figure out what we need
but it never fails what i want is always in yards
sylvia

[suzeeq]

Many yarns are put up to be 50 or 100gm and it says so on the labels, but they also include the yardage because most patterns now let you know the yardage needed. It's a more reliable way to show how much yarn you need. Different fibers don't weigh the same. 50 gms of cotton may have only 85-90 yds, but 50 yds of a soft wool has about 120 yds, so if you need 8 skeins for a pattern that calls for wool, you'd need to get 10 or 11 skeins of the cotton if you were to substitute it. That's a big difference.