The following code helps to find the height for a UILabel or UITextView

NSString *text = @"This is a sample text";
CGSize maxSize = CGSizeMake(maxWidth, FLT_MAX);
CGRect labelRect = [text boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:font} context:nil];
CGFloat height = labelRect.size.height;