Calculating the UPS Tracking Number Check Digit

What about Tracking Numbers starting with 'K'?

Parts of the code are a little messy, but it works!

Courier Class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.ComponentModel;

namespace MyApp
{
    static class Courier
    {
        public static CourierName GetCourier(string trackingNumber)
        {
            switch (trackingNumber.Length)
            {
                case 12:
                    return CourierName.FedExExpress;
                case 15:
                    return CourierName.FedExGround;
                case 18:
                    return CourierName.UPS;
                default:
                    return CourierName.Unknown;
            }
        }
        public static bool IsValid(string trackingNumber)
        {
            return IsValid(trackingNumber, GetCourier(trackingNumber));
        }
        public static bool IsValid(string trackingNumber, CourierName courierName)
        {
            // trim any extra characters
            trackingNumber = Regex.Replace(trackingNumber, @"[^0-9A-Za-z]", "").ToUpper();

            if (courierName == CourierName.FedExExpress) // fedex express method
            {
                return _ValidateFedExExpressCheckDigit(trackingNumber);
            }
            else if (courierName == CourierName.UPS) // UPS method
            {
                return _ValidateUPSCheckDigit(trackingNumber);
            }
            else if (courierName == CourierName.FedExGround)
            {
                return _ValidateFedExGroundCheckDigit(trackingNumber);
            }
            return false;
        }

        private static bool _ValidateFedExExpressCheckDigit(string trackingNumber)
        {
            char[] trackingNumberArray = new char[trackingNumber.Length];
            trackingNumberArray = trackingNumber.ToCharArray();

            //reverse array
            Array.Reverse(trackingNumberArray, 0, trackingNumber.Length);
            int sum = 0;
            int multiplier = 7;
            int check = 0;
            for (int i = 1; i < trackingNumber.Length; i++) //skip check digit
            {
                if (multiplier == 7)
                {
                    multiplier = 1;
                }
                else if (multiplier == 1)
                {
                    multiplier = 3;
                }
                else if (multiplier == 3)
                {
                    multiplier = 7;
                }
                sum += (Convert.ToInt32(trackingNumberArray.GetValue(i)) - 48) * multiplier;
            }
            check = sum % 11;
            if (check == 10)
            {
                check = 0;
            }

            if ((Convert.ToInt32(trackingNumberArray.GetValue(0)) - 48) == check)
            {
                // check digit passes
                return true;
            }
            else
            {
                // check digit fails
                return false;
            }
        }

        public enum CourierName
        {
            [Description("FedEx Express")]
            FedExExpress = 1,
            [Description("FedEx Ground")]
            FedExGround = 2,
            UPS = 3,
            OnTrac = 4,
            Unknown = 100

        }
        
        private static bool _ValidateUPSCheckDigit(string trackingNumber)
        {
            char[] trackingNumberArray = new char[trackingNumber.Length];
            trackingNumberArray = trackingNumber.ToCharArray();
            int checkDigit = 0;
            int sum = 0;
            for (int i = 2; i < trackingNumber.Length - 1; i++)
            {
                if (char.IsDigit(trackingNumberArray[i]) == false)
                {
                    if (Regex.IsMatch(trackingNumberArray[i].ToString(), "[A-H]"))
                    {
                        trackingNumberArray[i] = (char)(Convert.ToInt32(trackingNumberArray.GetValue(i)) - 15);
                    }
                    else if (Regex.IsMatch(trackingNumberArray[i].ToString(), "[I-R]"))
                    {
                        trackingNumberArray[i] = (char)(Convert.ToInt32(trackingNumberArray.GetValue(i)) - 25);
                    }
                    else if (Regex.IsMatch(trackingNumberArray[i].ToString(), "[S-Z]"))
                    {
                        trackingNumberArray[i] = (char)(Convert.ToInt32(trackingNumberArray.GetValue(i)) - 35);
                    }

                }
                if (i % 2 == 0) // adding all odd positions
                {
                    sum += (Convert.ToInt32(trackingNumberArray.GetValue(i)) - 48);
                }
                else
                {
                    sum += 2 * (Convert.ToInt32(trackingNumberArray.GetValue(i)) - 48);
                }

            }
            checkDigit = (int)(Math.Ceiling(sum / 10.0d) * 10) - sum; // round to the next highest ten (71 becomes 80)
            if ((Convert.ToInt32(trackingNumberArray.GetValue(trackingNumber.Length - 1)) - 48) == checkDigit)
            {
                // check digit passes
                return true;
            }
            else
            {
                // check digit fails
                return false;
            }
        }
        private static bool _ValidateFedExGroundCheckDigit(string trackingNumber)
        {
            char[] trackingNumberArray = new char[trackingNumber.Length];
            trackingNumberArray = trackingNumber.ToCharArray();

            //reverse array
            Array.Reverse(trackingNumberArray, 0, trackingNumber.Length);
            int sum = 0;
            int check = 0;
            for (int i = 1; i < trackingNumber.Length; i++) // skip position 0
            {
                if (i % 2 == 1) // every other digit multiplied by 3
                {
                    sum += (Convert.ToInt32(trackingNumberArray.GetValue(i)) - 48) * 3;
                }
                else
                {
                    sum += (Convert.ToInt32(trackingNumberArray.GetValue(i)) - 48);
                }
            }
            check = (int)(Math.Ceiling(sum / 10.0d) * 10) - sum;
            if (check == 10)
            {
                check = 0;
            }
            if ((Convert.ToInt32(trackingNumberArray.GetValue(0)) - 48) == check)
            {
                // check digit passes
                return true;
            }
            else
            {
                // check digit fails
                return false;
            }
        }
    }
}

Include in main class:

using System.Reflection;
namespace MyApp
{
class Program

    {
        public static string GetDescription(Enum value)
        {
            FieldInfo fi = value.GetType().GetField(value.ToString());

            DescriptionAttribute[] attributes =
                (DescriptionAttribute[])fi.GetCustomAttributes(
                typeof(DescriptionAttribute),
                false);

            if (attributes != null &&
                attributes.Length > 0)
                return attributes[0].Description;
            else
                return value.ToString();
        }
    }
}

Usage:

string message = "";
string trk = "123412349999";
if (Courier.IsValid(trk))
{
    // is valid
    message += GetDescription(Courier.GetCourier(trk)) + ": " + trk + " is valid.\n\r";
}
else
{
    // is not valid
    message += GetDescription(Courier.GetCourier(trk)) + ": " + trk + " is not valid.\n\r";
}

I was attempting to implement your function to validate UPS tracking numbers and it seemed to be fairly inconsistent in producing the correct check digit for real UPS tracking numbers that I was trying it with. It would be right about 25% of the time and off by 1 digit the rest of the time. I did a little research and found some information here that helped me make a few corrections to your function to get it working better for me.

A quick summary of the small changes I made:

1. I decided to strip out the "1z" and final (check) digit inside the function, it just seemed more convenient to pass the whole unaltered tracking number rather than stripping these 15 digits away outside the function.

2. Instead of subtracting 48 from the Alpha characters, I subtract 63 from them and then mod the result by 10. This results in the values from the Alpha to Numeric chart that can be found via the link above.

3. All even position values (both Alpha and Numeric) are multiplied by two and added to the total and all odd position values are simply added to the running total. This differs in that it does not matter if the value was derived from and Alpha or Numeric, it's multiplier is only dependent on it's position.

private int CalculateUPSCheckDigit(String trk)
{
    //Drop first 2 characters ("1Z"), take next 15 characters, drop final character (check digit)
    trk = trk.Substring(2, 15);

    int checkdigit = 0;
    char[] chars = trk.ToCharArray();
    int charindex = 1;
    int runningtotal = 0;
    foreach (Char ch in chars)
    {
        if ((charindex % 2) == 0) //Indicates character in even position
        {
            int testeven;
            if (Int32.TryParse(ch.ToString(), out testeven) == true) // Indicates numeric value
            {
                runningtotal += (2 * testeven);
            }
            else // Indicates alpha value
            {
                int asciivalue = System.Convert.ToInt32(ch);
                int n = ((asciivalue - 63) % 10) * 2; 
                runningtotal += n;
            }
        }
        else // Indicates character in odd position
        {
            int testodd;
            if (Int32.TryParse(ch.ToString(), out testodd) == true) // Indicates numeric value
            {
                runningtotal += testodd;
            }
            else // Indicates alpha value
            {
                int asciivalue = System.Convert.ToInt32(ch);
                int n = (asciivalue - 63) % 10;
                runningtotal += n;
            }
        }
        charindex++;
    }
    
    int y = (runningtotal % 10);

    if (y == 0)
    {
        checkdigit = y;
    }

    else if (y > 0)
    {
        checkdigit = (10 - y);
    }   

    return checkdigit;
}

I also used the page linked above to create a function to calculate the check digit value of FedEx tracking numbers if anyone would be interested.

Thanks,
David Bowker

Good work David!

I'll have you know I used your code!

Hello David, I'd be very much interested in your function for the FedEx tracking number check digit. My email is normanpaterson@hotmail.com

Perhaps you might consider posting it on CodeProject.com? Or if you like I can post it for you, just let me know.

Thanks,
Norman

Here is my code to generate the FedEx check digit. This should be equal to the last (12th) digit of the FedEx tracking number. Hope you find it useful!

private int CalculateFedExCheckDigit(String trk)
    {
        //--- Take first 11 digits of tracking #
        trk = trk.Substring(0, 11);

        int checkdigit = 0;
        char[] chars = trk.ToCharArray();
        int charindex = 1;
        int runningtotal = 0;
        foreach (Char ch in chars)
        {
            if ((charindex % 3) == 0) //Indicates character in 3rd position
            {
                runningtotal += (Int32.Parse(ch.ToString()) * 7); // Multiple Value by 7 & Add to Total
            }
            else if ((charindex % 2) == 0) // Indicates character in 2nd position
            {
                runningtotal += Int32.Parse(ch.ToString()); // Multiple Value by 1 & Add to Total (Just Add Value)
            }
            else // Indicates character in 1st position
            {
                runningtotal += (Int32.Parse(ch.ToString()) * 3); // Multiple Value by 3 & Add to Total
            }
            charindex++; // Increment Index
        }

        //--- Get remainder of total after dividing by 11
        int y = (runningtotal % 11);

        //--- If remainder == 10, set value = 0, else set value = remainder
        if (y == 10)
        { 
            checkdigit = 0; 
        }
        else
        {
            checkdigit = y;
        }

        return checkdigit;
    }

Here is a compact PHP Version. I have tested with Worldship and it appears to work.
In this example Tracking number is generated with an Order ID, truncated to right 5 digits, and a '0' padded box number of the shipment. The tracking number is sent with the '1Z' already stripped. For ground service the Service Level is '03'.

Has anyone determined how a multipackage shipment is imported into Worldship and is grouped together?

$Tracking = $ShipperID . $ServiceLevel . substr($OrderID,-5) . sprintf("%02d", $i);
$Tracking = '1Z' . $Tracking 	. CalculateCheckDigit($Tracking);

function CalculateCheckDigit($trk) {
	$array = str_split($trk);
	$runningtotal = 0;
	$charindex=1;
	foreach($array as $ch) {
		if(!(is_numeric($ch))) { //Convert ASCII to numeric
			$ch = (ord($ch)-63) % 10;
		}
		$runningtotal += $ch;
		if(!($charindex % 2)) { //Character in even position is doubled
			$runningtotal += $ch;
		}
		$charindex++;
	}
   $checkdigit = ($runningtotal % 10);
   $checkdigit = ($checkdigit==0 ? $checkdigit : 10-$checkdigit);
   return $checkdigit;
}

Calculating the UPS Tracking Number Check Digit

Introduction

Using the code

License

Comments and Discussions