There's one on the net-simple to use.
http://www.theboltons.plus.com/Calculator.html
If you want to convert numerical values to log^10 values, all you need is a scientific calculator. Try this:
>start
>all programs
>accessories
>calculator
Make sure the calculator is toggled to ‘scientific’ mode. Then, enter the numerical value and click on ‘log’. That should give you a translation.
Take care—
Bill