You can enter data with different measurement units, and standardize all collected data with the same measurement unit with a calculation. For example, let's say that you are collecting the medication dose, which can be entered in mg, g, and kg. With a calculation you can automatically show all medication doses in grams:

Use the following template and replace the units_field and dose_field with your own fields.

if('{units_field}'=='mg'){
{dose_field}/1000;
} else if('{units_field}' == 'g'){
{dose_field};
} else if('{units_field}' == 'kg'){
 {dose_field}*1000;
}