estimate yardage when using a different weight of yarn

I would like to knit half + half triangle wrap in the smaller size.

This pattern is designed for fingering weight yarn and for the smaller size, estimates 791 yards and 845 yards for color A and color B respectively.

I want to knit it in DK weight yarn! Can I still expect to need ~791 and ~845 yards respectively? How would knitting it in DK change the yardage?

My guess is that the yardage is going to be similar depending on the gauge of the DK you want to use. You may need to work with fewer sts since you’re using a heavier weight yarn. A swatch is going to be very helpful here both for the drape and feel of the knit fabric and the gauge.

The key to knitting anything is swatch, swatch, swatch. Use the yarn you want to use for the project as well as the same size needles. If using smaller and larger needles, as for a jumper, use the larger size needles for your swatch. This will give you a good gauge as well as how much yarn you’ll need for your project.

If you haven’t swatched before, you might want to check out these instructions.
https://ysolda.com/blogs/journal/learn-to-knit-how-to-knit-a-swatch#:~:text=Work%20a%20few%20rows%20of,the%20sides%20from%20curling%20inward.