Zend_Validate_LessThan allows you to validate if a given value is less than a maximum border value. It is the cousine of Zend_Validate_GreaterThan. It should be noted that Zend_Validate_LessThan supports only the validation of numbers. Strings or dates can not be validated with this validator. The following options are supported for Zend_Validate_LessThan: max: Sets the maximum allowed value. To validate if a given value is less than a defined border simply use the following example. 10)); $value = 10; $return = $valid->isValid($value); // returns true ]]> The above example returns TRUE for all values which are equal to 10 or lower than 10.