well you can try this :
NSDictionary *attributes = @{NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue" size:14]};
// NSString class method: boundingRectWithSize:options:attributes:context is
// available only on ios7.0 sdk.
CGRect rect = [textToMeasure boundingRectWithSize:CGSizeMake(width, CGFLOAT_MAX)
options:NSStringDrawingUsesLineFragmentOrigin
attributes:attributes
context:nil];