Here are more calculators..
There are many tire aspect combinations to get close to the width and tire height you want. i.e. You can go to wider width, say from 255 to 285, and actually a lower overall height by changing the series say from a 70 to a 60.
You can use the calculators to get to as close to the overall width and height you desire and then see if they make a tire in that width and series.
You will find that there are popular tire sizes and these will be the cheapest.
You can also plug height numbers into the other calculator to check RPM changes at different speeds with different tire heights.