Add 1/4 inch all around.
Approximately 1 x 5+
I decided to make it 4 inches to give something to hold on.
Be careful not to pull back out.
This is why the extra length was added.
Do you see the mistake?
Has to do with top stitching.
Thinking the strap would be a place to use a decorative stitch?
Or make the strap wider if you like?