The following are the common causes of errors that occur when you set a formula.

There is a possibility that a field code in the formula is not specified correctly.
Click the gear-shaped Settings icon at the upper right of the target field, and then click Settings to open the field settings screen. At the bottom of the screen, check the "field code" displayed.

Field codes can be changed.
If you change the field code of a field referenced in a formula, the field code specified in the formula is also changed automatically.

The formula may contain full-width symbols, such as full-width parentheses (), ampersand symbol &, and four arithmetic symbols + - * /.
Make sure you use half-width symbols in your formula.

• Example of a formula: IF(Total>=80,"OK","ERROR")

There is a possibility that an operator in the formula is not specified correctly.
If what the error message says applies to you, replace the mistyped operator with the correct operator indicated by the message.
The following page describes the operators that can be used in kintone.
Description of Operators

There are fields that can be referenced in formulas and those that cannot.
The following page describes which fields can be referenced in formulas and which cannot.
Fields That Can/Cannot Be Referenced in Formulas

The following are the possible causes. Check if any of the following applies to your formula.

• Parentheses are not paired.
• An operator is placed in an incorrect position.
• A line break is inserted in the middle of a string enclosed in double quotation marks ("").
• A line break is inserted in the middle of a numeric value.
  
  

In addition to the above, the error may be caused due to other reasons; for example, an incorrect number of arguments are specified for a function or an invalid function is specified in the formula. The details of the errors related to formulas are explained in the following page:
Formula Errors