Use the toNumber() function to convert a string field to a number.

When using the toNumber function, test the value first with the isNumeric() function. isNumeric() returns a value of TRUE only if the value in the string can be correctly converted to a number. Otherwise, if a value to be converted to a number cannot be, the formula will produce an error in the report.

The following example is a common use of the isNumeric() and toNumber() functions together:

If isNumeric({String_Field}) then toNumber({String_Field}) else 0