I am crocheting a baby blanket in zig zag form. Calls for chain of 155. How do I increase size for larger?

Since it is ripple design, has increase & decrease, double & triple crochet I don’t know how to increase it to measure for a larger child. Calls for beginning chain of 155 & I would like it to be 1/2 size larger.

What I would try is crocheting a chain of 233 stitches and work the pattern to make sure it comes out the way you want it. If this doesn’t work, there are a ton of ripple afghan patterns out there that may work for you.

Crochet Zig Zag baby blanket