Don't know how helpful this is to you, but I'll post it anyway. Having a chart is quicker than calculating it yourself.
And yes, I do know that it would be easier to read in an html table and yes, I do know how to do that, but I can't be bothered right now. I'll do it later.
Assume the following:
The duration of an Oddworldian year equals an Earth year.
Human lifespan = 80 years
Mudokon lifespan = 40 years
Glukkon lifespan = 65 years
Slig lifespan = 20 years
Gabbit lifespan = 18 years
Vykker lifespan = 120 years
:
Human age Corresponding Oddworldian age
Mud Glukk Slig Gabbit Vykker
5 2.5 4.06 1.25 1.125 7.5
10 5 8.1 2.5 2.25 15
15 7.5 12.2 3.75 3.375 2.5
18 9 14.6 4.5 4.05 27
21 10.5 17.06 5.25 4.725 31.5
25 12.5 20.3 6.25 5.625 37.5
30 15 24.3 7.5 6.75 45
40 20 32.5 10 9 60
50 25 40.6 12.5 11.25 75
60 30 48.75 15 13.5 90
70 35 56.8 17.5 15.75 105
80 40 65 20 18 120
90 45 73.1 22.5 20.25 135
100 50 81.25 25 22.5 150