Re: Is there a way to test in a formula if a text field contains a valid number?

That could be a problem. What if it was a blank? And the tonumeric also returns a blank. Then they both will be equal, thus misleading us to believe that a blank is numeric. 

I guess, we need to first filter out blanks and call them non-numeric right away before checking for non-blanks.

if (Contains([may be a number]," ",false,ToText(ToNumber([maybe a number]))=[maybe a number])