I have been playing around with converting 4e monsters to 5e to be able to use 4e resources for 5e play. I want something quick and easy that can be done in the fly. Here is what I am using.
AC is calced based on equipment and dex.
HP is 4e HP minus 20 (minus 40 for elites and minus 80 for solos).
Attack bonus is prof bonus (based on level) plus the appropriate stat.
For damage use the listed damage values plus level.
A couple special rules:
If you want a monster to have some natural armor then 13 is the default. It can be adjusted up or down as desired (I do +/-2 intervals).
If a power requires an action or move type not typically in 5e (e.g. charge, shift) then just use the 4e rules for it.
I have only done low level so far but it is working pretty well. I don't really calc CR and just play it by ear. This gives a lot of monster variety.
AC is calced based on equipment and dex.
HP is 4e HP minus 20 (minus 40 for elites and minus 80 for solos).
Attack bonus is prof bonus (based on level) plus the appropriate stat.
For damage use the listed damage values plus level.
A couple special rules:
If you want a monster to have some natural armor then 13 is the default. It can be adjusted up or down as desired (I do +/-2 intervals).
If a power requires an action or move type not typically in 5e (e.g. charge, shift) then just use the 4e rules for it.
I have only done low level so far but it is working pretty well. I don't really calc CR and just play it by ear. This gives a lot of monster variety.