What is going next to the sink? You seem to have a large space there so what is it being used for?

That sounds like good use of extra tile & would add a little bling to laundry area. But - full wall? You mean up to window & width of sink? How much tile do you have left? I think the challenge is that window isn’t centered over sink so going up to window gives odd stopping points on both sides of sink. How about going to top of curve in faucet spout? That would provide a high splash back - helpful for small dog bathing - and create a look of logical stopping point. Maybe a narrow shelf or paper towel holder above the tile would be handy depending on what you might put next to sink as Patricia Colwell asked..

Thank you, these are helpful
comments and questions. To the left of the sink I’m going to put a wood storage cabinet with 2 doors, where I can put an ironing board and store boots, etc. I think I’d need to tile the entire wall (that is visible), including above the window, to make it a cohesive look/ not choppy. We may need to buy more subway tile but it’s not expensive, and I was thinking the grout could be the alabaster color, the same as the floor grout. My contractor is going to build a wood shelf over the washer/ dryer for folding clothes, and above that I was going to put a wood shelf the length of the washer/ dryer.