Answer by Sargis for How to detect number length in UITextField?

Use this.

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{// _textLenghtLimit = your text max lenght    if (_textLenghtLimit > 0) {        if ((range.location >= _textLenghtLimit || textField.text.length + 1 > _textLenghtLimit) && range.length == 0) {            return NO;        }    }    return YES;}