Systems and methods are provided for building and implementing formulas. The systems and methods may treat operands in a formula as having a value and a unit type or dimension and may recognize the compatibility of unit types among operands. One embodiment performs automatic error checking of a formula based on the value and dimension of the operands and the expected result. The automatic error checking may be performed to assist a user in defining and building a formula. Another embodiment performs automatic unit conversion based on the value and unit type of the formula's operands. The automatic unit conversion may be performed when applying data to the formula during runtime or execution of an application program.