Creating a solution > Working with formulas and functions > About functions
About functions
A function is a predefined, named formula that performs a specific calculation and returns a single, specific value.
Most functions include three basic parts:
the function name
a set of parentheses, if the function takes parameters
the parameters required by the function
Each function returns a result of field type text, number, date, time, timestamp, or container.
For information about where functions can be used, see About formulas.
Note  For information on how functions evaluate differently on the host versus the client, search the FileMaker Knowledge Base.
Function parameters can be constants (such as 1.07 or "hello"), field references (such as InvoiceTotal), expressions (such as 1 + 12), or other functions (such as the NPV function). You can use spaces before or after the parentheses used to enclose the parameters, but spaces are not necessary. When a function requires more than one parameter, separate individual parameters with a list separator, such as a semicolon.
Braces ({ }) surround optional parameters (for example, the Case function and Choose function). An ellipsis (...) signifies that you can add more parameters, each separated by a semicolon (for example, in aggregate functions). Double quotation marks (" ") indicate a text string.
Literal text parameters such as filenames and layout names must be enclosed in quotation marks. Use quotation marks around field names to indicate the literal string is the parameter (omit quotation marks to indicate the value stored in the field is the parameter). You can use spaces before or after the parentheses that enclose parameters, but spaces are not necessary. Use a semicolon between parameters when a function requires more than one parameter.
This table shows examples of some FileMaker Pro functions.
This function
4, the number of characters in the text "John"
The amount of sales tax rounded to two decimal places
Position(Name, "Mc",1,1)
A number representing the starting position of one text string within another, in this case indicating the position of the first occurrence of "Mc" in the Name field
A number representing the error (if any) in the most recently executed script step in the currently running script
The total of all the values in the repeating field ExtendedPrice
Related topics 
Functions reference (alphabetical list)
Aggregate functions
Date functions
Design functions
Financial functions
Get functions
Logical functions
Number functions
Repeating functions
Summary functions
Text functions
Text formatting functions
Time functions
Timestamp functions
Trigonometric functions