How to use gauge to fit different needle and yarn?

How-to Questions
1

I am attempting a baby blanket but the needle and yarn that is used is different from my needle and yarn. This is the gauge given:

14 sts = 4 inches (10 cm). BE SURE TO CHECK YOUR GAUGE. When you match the gauge in a pattern, your project will be the size specified in the pattern and the materials specified in the pattern will be sufficient. If it takes you fewer stitches and rows to make a 4 in. [10 cm] square, try using a smaller size hook or needles; if more stitches and rows, try a larger size hook or needles.

That blanket is made on US 11 needles with a light bulky weight yarn. But I am using US 7 and worsted weight yarn. The pattern says to cast on 123 stiches, so what should be the new amount for me to cast on? Thanks

2

Take the 123 sts and divide it by the pattern gauge which equals 35" wide for the blanket. Knit a sample with your yarn and needles to see how many sts/inch you get, then multiply that by 35 to see how many sts you need. I will mention that size 7s will probably give you a fairly dense knit unless you’re a loose knitter; you might think about using size 8 or 9 for a softer more open pattern like the original.