Can anyone tell me that if a pattern calls for a 50g ball of yarn at 104 yds in length and I’m substituting a yarn that equals 50g at 140 yds in length - will I basically be using more or less of the substitution yarn? Off the top of my head I would think it would be less. However, I’m not sure if a possible change in needle size (in order to obtain correct gauge) will affect anything. If I have an appr. idea of whether it is usually more or less, I can prevent a huge over purchase of yarn. I find that, for the most part, I tend to over calculate yardage for fear of not finding yarn in the same dye lot.
Assuming you’re using the same weight of yarn, you don’t really need to compare the pattern yarn to the yarn you wish to use. I would just look at the total yardage required for the project and make sure you get enough (in terms of yardage) of your chosen yarn.
For example, if your pattern requires 500 yards and the yarn you want to use comes in skeins of 140 yards each then you would need to get at least 4 skeins.
Even though (I’m assuming) you are using a yarn of the same weight as called for in the pattern, gauge may vary slightly depending on the yarn (as you suggested). So I would probably pick up an extra skein of yarn and make sure I do a good gauge swatch to be sure.
The pattern should tell you how much yardage you need for your size. Just figure out how many skeins you need. And I always buy and extra skein or two. Better to have extra than having to hunt down a few later.
For example - if you need 1200 yds for a sweater -
1200 divided by 140 = 8.5 skeins- So you’d buy a [I]minimum[/I] of 9 skeins.
If the yarn is a different gauge then all bets are off. First you’d have to figure out how many yds you’d need with that weight yarn, then figure what size you’d make with that weight to have it fit you…etc…
pattern calls for a 50g ball of yarn at 104 yds in length and I’m substituting a yarn that equals 50g at 140 yds in length
These yarns are not the same weight, one gets nearly 40 more yards out of the same weight as the other, so it has to be lighter. You would not likely be able to knit the same gauge with the same needles on both.