How to read an international tracking number

Most international post uses one shared numbering format, set by the Universal Postal Union and known as S10. Once you can read it, a tracking number tells you what kind of item you have, which country accepted it, and whether you have typed it correctly.

A typical number looks like this: EE 123 456 785 IN. It has 13 characters, split into four parts.

The four parts

Two service letters: EE

These describe the type of item. The first letter carries most of the meaning: E usually means express (EMS), R registered, C parcel, and L a tracked or express letter. The second letter is chosen by the postal service itself.

Eight serial digits: 12345678

These identify this one item among everything using the same prefix.

One check digit: 5

This is calculated from the serial number. It exists purely to catch mistakes.

Two country letters: IN

The standard code for the country that issued the number. IN is India, GB the United Kingdom, FR France, US the United States.

How the check digit works

Each serial digit is multiplied by a fixed weight, and the results are added together. For the serial 12345678:

1. Add the bottom row: the total is 204.
2. Divide by 11 and keep the remainder: 204 ÷ 11 leaves 6.
3. Subtract that from 11: 11 − 6 = 5. That is the check digit.

There are two special cases. If the subtraction gives 10, the check digit is 0. If it gives 11, the check digit is 5.

This is why a single wrong digit almost always produces an invalid number. Our tracker runs this calculation as you type, so it can warn you about a typo before you waste time searching.

What the country letters don’t tell you

The last two letters show where the number was issued, not where the parcel is now or where it is going. A number ending in IN stays the same after the parcel has left India. It can also be a domestic item that never crosses a border.

Numbers that don’t follow this format

S10 is mainly used by national postal services. Private couriers have their own systems:

• UPS numbers usually have 18 characters and start with 1Z.
• USPS domestic numbers are commonly 20 to 22 digits.
• FedEx numbers are commonly 12 or 15 digits.
• DHL Express waybills are commonly 10 digits.

These lengths overlap between companies, so a number of digits alone rarely identifies a courier with certainty. If you are not sure, your order confirmation should name the courier. You can also browse our courier directory.

Seeing the check digit catch a mistake

Suppose the receipt says EE 123 456 785 IN, but the eighth serial digit is misread as a 9. The serial becomes 12345679, and the same calculation now gives a check digit of 9. The number still ends in 5, so it can’t be right.

Swapped digits are caught too. If the last two serial digits are switched, giving 12345687, the check digit should be 3 rather than 5. Because each position has its own weight, moving a digit usually changes the result.

What a correct check digit doesn’t prove

A valid check digit only shows that the number is correctly formed. It doesn’t show that:

• the number has actually been issued to a parcel
• the parcel has been handed to the courier yet
• the number belongs to your parcel, rather than someone else’s
• the sender is genuine, because scammers can quote realistic numbers

Treat it as a typing test and nothing more. Only the courier’s own tracking page can tell you what has happened to a parcel. If you have an Indian postal number, our guide to tracking Speed Post explains the next step.