Use cell properties with a custom number that ends in 3 spaces, filling when
shorter or cutting when longer.
In the cell, set of cell you want to change left click select cell
properties, custom and write under type : "#,##0.000" whitout quotes, then
click OK.

This will do.

"
wrote in message
...
I would like to force a user to enter a number that contains a decimal and
three spaces beyond (0.000). I think this can be done with the Data
Validation feature but I am having difficulty writing the formula. The
number of places to the left of the decimal can be limitless and the
number
to the right could be less than 3, but I need to have the 'missing' places
populated with zeros.