Hi
Here is one suggestion:
A B C D
Input Output
l/h l/s l/h l/s
60 0.520 1872 0.017

In columns A and B you have your free text input i.e. you enter the figures.
In column C and D you have your calculations for l/h and l/s.
When you change any entry in columns A or B your output columns are then automatically recalculated.
You could also lock columns C and D so no one can change them by accident.
Hope this helps.
Good luck.
Tony