Hi, so I just learned knitting over Christmas break 
and I’m making my first scarf and I’m just wondering I guess like what happened if I use a size 3 needle or a size 10? Can someone just explain to me like how the stitching is different? Does a bigger needle use more yarn to finish a scarf?
Hi and welcome1
The size of the needle determines how big the stitch is and how many stitches you can get per inch (gauge). A larger needle will give you fewer sts/inch, a smaller needle will give you more sts/inch. There’s a good video for gauge here (about halfway down the page) to give you an idea of how important it is to knitting projects to the desired size.
Thank you. So if I’m just doing a basic scarf does it really matter what size I use?
For your first project I suggest you use a worsted weight wool and at least a US sz 8 needle, 9 or 10 might be better. You don’t want to use a size 3 needle with a fatter yarn, save the small sizes for when you’re ready to work with finer yarn for things like socks. One more thing, if you don’t use a pattern, you probably won’t want to work the whole thing in stockinette stitch, that’s where you knit a row, purl a row, and continue alternating, as it will curl. There are ways to avoid the worst of the curling, ask if you’re wanting to use stockinette stitch. Welcome to Knitting Help and the wonderful, wacky world of knitting!
So I think what I’m wondering is, if I use a bigger needle, does that make the yarn go further? Like does bigger or smaller needles make it go quicker? If that makes sense
Yes, the yarn you choose will point you to a range of needle sizes. Do you have a yarn in mind or a pattern that you’d like to use?
Well the friend that taught me just gave me an extra thing of yarn she had so it didn’t have like any info on it. It’s more like a ribbon than yarn though. I’ve started it, I think the needles she gave me are about an 8. My problem is I’ve been trying to find another ball of this ribbon for when I run out but I can’t find it anywhere so I was just wondering if I use a bigger needle if that would make it go further
If you use a larger needle and cast on fewer stitches, it’ll use less yarn. The project will be looser or airier and that may be just fine for the scarf you’re making. Try it out with the larger needle and see if you like the look of the knitted fabric. Otherwise, maybe you can knit some with the ribbon, change to another yarn and then finish up with more of the ribbon.
Use the size 10s with a medium weight yarn, thought the 8s might be good too. The size 3 is for thin yarn like sock or baby yarns (though some baby yarns are pretty thick).
Smaller needles will be more sts per inch, so if you want something about 7" wide and you get 6 sts per inch, you need 40 stitches or more. But if you use a larger needle and get 4 sts per inch, you only need 30 sts. Since the bigger needles make larger stitches and rows you don’t need as many stitches as you do with the small needles and end up using less yarn for the same measurement. If you use the same number of stitches with the big needles as the smaller ones, you’ll use more yarn, but will end up with something a lot larger.
The best thing you can do is make a swatch or sample to see what different size needles do and see if you like the fabric. But, basically if you use a smaller needle your gauge is tighter and a bigger needle is looser… How much yarn you use is dependent on both needle size and yarn weight.
I have made several lacy scarves with fingering or sock weight yarn. The yarn suggested a size 1 or 2 needle, but I used an 8 so it came out lacy like I wanted.