A seller sends you a string of digits with no carrier name. Or you find a label in a drawer and want to know who carried it. Tracking numbers are not random - each carrier uses a recognisable structure, and once you know the patterns you can identify the carrier in a couple of seconds. ## USPS USPS numbers are long and numeric. The most common consumer format is **22 digits**, frequently displayed in groups of four, and typically beginning with 92, 93, 94 or 95. These are IMpb - Intelligent Mail package barcode - numbers, which encode the service type and the mailer. You will also see: - **20-digit** numbers for some services - **13-character UPU format** such as two letters, nine digits and two letters ending in US, used for international items originating in the US - **Certified and registered mail** numbers, also long and numeric, usually starting 70 or 94 If a number is over 20 digits and purely numeric, USPS is the overwhelmingly likely answer. ## UPS UPS is the easiest of all to recognise. The standard format is **1Z followed by 16 characters** - a six-character shipper number, a two-digit service code and a sequence with a check digit. If a number starts with 1Z, it is UPS, with no realistic exceptions. UPS also issues: - **Nine-digit** freight and package reference numbers - **12-digit** numbers for certain services - **T-prefixed** numbers used on some international and returns products ## FedEx FedEx numbers are numeric and typically **12 or 15 digits**, with **20 and 22 digit** formats also in circulation for Ground and SmartPost-type services. Because FedEx and USPS both use long numeric strings, the distinguishing tell is the leading digits: USPS numbers commonly begin 92-95, whereas FedEx Ground numbers frequently begin with a shipper-specific prefix and FedEx Express numbers are usually 12 digits. If a 12-digit number does not work on USPS, try FedEx first. ## DHL DHL splits by division: - **DHL Express** uses a **10-digit** number, often starting with a 1, 2, 3 or a JD-prefixed longer form for eCommerce - **DHL eCommerce** uses longer alphanumeric strings, frequently beginning **JJD, JVGL or GM** - **DHL Parcel** in Europe uses country-specific formats A short 10-digit number is almost always DHL Express - no other major carrier uses that length as a primary consumer format. ## Amazon Amazon Logistics numbers begin with **TBA** followed by digits. These are only trackable in the Amazon account or through the Amazon tracking page - they do not resolve on any third-party carrier site because the delivery is performed by Amazon's own network of delivery service partners. If you see TBA, stop searching elsewhere. Amazon's order page is the only source. ## The UPU international format The 13-character format - **two letters, nine digits, two letters** - is defined by the Universal Postal Union and used by postal operators worldwide. The first two letters indicate the service class and the last two indicate the country of origin: | Prefix letters | Typical meaning | |---|---| | Starts with E | Express Mail Service | | Starts with C | Parcel, signature | | Starts with R | Registered mail | | Starts with U | Unregistered or unspecified | | Starts with L | Express, no signature | | Ends CN, GB, DE, US | Country of origin | The huge practical advantage of this format: the same number works on both the origin post's website and the destination post's website. If the origin has stopped updating, check the destination. ## Other carriers you may encounter - **Royal Mail** uses the UPU 13-character format for international and a longer alphanumeric for domestic tracked services - **Evri and DPD** in the UK use their own numeric or alphanumeric references, usually entered on their own portals - **China Post, Yanwen, 4PX and Cainiao** issue either UPU-format numbers or long carrier-specific strings; aggregators are the practical way to resolve these - **OnTrac, LaserShip-derived regional carriers** use their own formats and are frequently the final-mile leg for larger retailers ## What to do with an unidentified number 1. Paste it into a **multi-carrier aggregator**, which pattern-matches against dozens of formats and queries the likely carriers automatically. 2. Check the **order confirmation email** - the carrier name is usually there even when the tracking widget hides it. 3. If the number starts with TBA, use **Amazon**. If it starts with 1Z, use **UPS**. If it is 13 characters ending in a country code, use the **destination post**. 4. If nothing resolves, the number may be a **seller-internal reference** that has not yet converted to a carrier number. This is common in the first 24-48 hours after an order and resolves on its own. ## Why a valid number sometimes shows nothing A brand-new number often returns "not found" because the label was generated but the parcel has not been scanned into the network yet. Give it 24-48 hours. Persistent no-results after several days usually means the shipment was never lodged - contact the seller rather than the carrier, because the carrier has no record to discuss. ## Bottom line 1Z means UPS. TBA means Amazon. Ten digits means DHL Express. Twenty-two digits starting 92-95 means USPS. Twelve or fifteen digits means FedEx. Two letters plus nine digits plus a country code means a postal service, trackable at both ends. Learn those six patterns and you will almost never have to guess again.