How to figure amount of yarn needed?

[Strgzr]

Here's info- (I'm not sure how many skeins of smaller yarn I need):

pattern calls for 2 balls of:

Bernat Home Bundle( it has 4 different thicknesses in each ball)

207 yards/8.8 oz/5-6wt/10st-4"-ball says use L hook, pattern calls for N hook

....

yarn I want to use:

186yd/4oz/4wt/12st-4", yarn calls for J hook. 

 

[Granny Square]

Typically you want to (mostly) ignore the hook size on the ball band.  The important thing is the 2 yarns should be the same weight class; you don't say so, are they?

So, your pattern calls for 414 yards of super bulky (US #6).  'Your' yarn is only 186 yards per skein, 2 skeins would be 376 yards.

If the 2 yarns were compatible weight-wise, I personally would buy 3 skeins of your preferred yarn.  You take a chance that the pattern calls for 2 skeins of the other because the designer used up 1.5 skeins--but on the other hand, many times I've bought 1 more skein than I "should" have needed even of the 'right' yarn, and have had to break into the extra skein for a little bit.  My 'yarn stash' is an assortment of full or almost full 'extra' skeins, but I always have enough on hand for a small project in a pinch...

Even though I said to ignore the ball band, and for all we know the designer used every inch of those 2 skeins, with the info you gave I'd be even more inclined to buy that extra skein.  Reason is...even if your preferred yarn and the Bernat are classed the same, a yarn class is a range...the fact that there is also a range in the ball band hook recommendation, if 'your' yarn is on the smaller end of the super bulky range than the Bernat, you are more likely to need more yardage (found that out the hard way).  And maybe you'll have enough left over for a cat toy 

[Ellie 13]

I add the yardage of the balls called for, then take the yarn I want to use and add the yards until it equals more than the yardage called for. Yarn called for 207 X 2 = 414, yarn wanted 168 X 3 = 504. Since you get more stitches/per 4" with the yarn you want, you should add an extra skein (4 skeins), better to have too much  . If you want the pattern to be the same size, make a swatch.

[Strgzr]

Villager re wt size, I did state them..the pattern yarn has mix of 4 types in one skein, is why it shows #5-6 wt, where yarn I want is #4. So guess I'll get 4 skeins..tks