There's different # strands available in stranded wire. Digi-Key's ruler has "7-strand wire holes" which I find wrong, nobody connects such stiff wire to a PCB, and the holes are way too small i.e. #16 AWG is 1.53mm, #14 1.93mm holes. Who has drill bits that size anyhow?
My notes:
#16AWG, Carol C2065 1.6-1.7mm hole works well and I am going with 1.8mm drill size.
#18AWG, Belden 8522 1.5mm hole works well and I am going with 1.6mm drill size.
I tried math using the advertised OD (for 19-strand wire) then adding say 20% but it doesn't work that good.
Also the insulation thickness varies a lot, so you end up needing almost double the diameter in the end, for your PCB footprint of space.