What Is a FedEx Reference Number? 2026 Guide to Tracking
TL;DR
A FedEx reference number is an optional, shipper-assigned code (up to 50 characters) used to organize and identify packages by purchase order, invoice, or other internal business records. It is not the same as a FedEx tracking number, which FedEx auto-generates for every shipment. You can use a reference number to track a package on fedex.com, but you’ll also need the sender’s FedEx account number and an approximate ship date to get results.
What Is a FedEx Reference Number?
A FedEx reference number is a custom alphanumeric code that the shipper assigns to a package when creating a shipment. It can be up to 50 characters long and typically maps to an internal business record like a purchase order, invoice number, or customer account ID.
The key thing to understand: this is not a tracking number. FedEx generates tracking numbers automatically for every shipment. Reference numbers are optional. The shipper chooses whether to add one, and what value to use. Think of it as a label the sender sticks on for their own bookkeeping, one that happens to be searchable in FedEx’s system too.
If you’ve received a reference number from a seller or your company’s shipping department and you’re wondering what it means, it’s simply their internal identifier for your shipment. According to FedEx’s developer documentation, valid reference types include purchase order numbers, customer references, invoices, bills of lading, part numbers, and Transportation Control Numbers.
FedEx Reference Number vs. Tracking Number
This is where most confusion starts. People encounter a FedEx reference number and assume it works the same way as a tracking number. It doesn’t. Here’s how they differ:
| Attribute | Tracking Number | Reference Number |
|---|---|---|
| Created by | FedEx (auto-generated) | The shipper (manually or via software) |
| Format | Numeric only; 12, 15, 20, or 22 digits | Alphanumeric; up to 50 characters, free-form |
| Required? | Yes, every shipment gets one | No, completely optional |
| Purpose | Public transit visibility | Internal organization, cross-referencing business records |
| Uniqueness | Globally unique per package | Not guaranteed unique, the same reference can appear on multiple shipments |
| Shared with recipient? | Always | Sometimes (printed on label, but not always communicated) |
FedEx tracking numbers follow strict formats. FedEx Express numbers start with “3” or “9” and run 12 to 15 digits, while FedEx Ground numbers start with “7” or “96” and run 12 to 20 digits. Reference numbers have no such rules. A reference could be “PO-2025-04821” or “SMITH-ORDER-77” or just “12345.”
If you’re trying to understand what’s printed on a package you received, our complete shipping label guide breaks down every field you’ll see.
Types of FedEx Reference Numbers
FedEx doesn’t limit you to one generic reference field. The system supports several specific types, and shippers can include multiple references on a single label:
- Customer Reference — The general-purpose field. An Etsy seller might enter order #4821 here so they can look it up later if the buyer asks about delivery status.
- Purchase Order (PO) Number — Common in B2B shipments. The receiving warehouse matches the PO to their records when the package arrives.
- Invoice Number — Ties the shipment to a billing document, useful for accounting reconciliation.
- Department Number — Helps large companies allocate shipping costs to specific departments in FedEx billing reports.
- RMA Number — Return Merchandise Authorization. When a customer sends something back, the RMA number links the return to the original complaint or warranty claim. If you’re setting up a returns process, our guide on creating prepaid return labels covers the practical steps.
- Bill of Lading (BOL) — Used primarily for freight shipments.
- Part Number — Manufacturers use this to connect shipments to specific components.
- Transportation Control Number (TCN) — Government-specific identifier for military and federal shipments.
According to Shippo’s carrier reference documentation, FedEx supports two reference fields per label (reference_1 and reference_2), so shippers can combine a PO number with a department code on the same package.
Where to Find a FedEx Reference Number
Reference numbers show up in several places:
- On the shipping label itself, typically printed in the reference field area near the barcode
- In FedEx Ship Manager, under the shipment record’s package details
- In shipment confirmation emails sent by FedEx or the shipping software
- On the FedEx invoice or receipt
- In third-party shipping platforms like Shippo, ShipStation, or ShipEngine, within the shipment details view
If you’re the recipient, the most reliable place to look is the physical label on the box. The reference field is usually below the tracking barcode. If you can’t find it there, ask the sender directly, since they’re the ones who created it.
How to Track a FedEx Package by Reference Number
FedEx lets you search for shipments using a reference number instead of a tracking number. This works across FedEx Express, FedEx Ground, FedEx Freight, and FedEx Ground Economy.
Here’s how:
- Go to fedex.com/tracking
- Look for the “Track by Reference” option (under “All Tracking Services”)
- Enter the reference number
- Enter the sender’s FedEx account number (this is required)
- Set the ship date range to narrow results
- Enter the destination country and postal code
- Click “Track”
The detail most guides skip: Track-by-reference won’t work without the sender’s FedEx account number. If you’re a recipient trying to track your package and all you have is a reference number, you’ll need to contact the sender for their account number or ask them to provide the tracking number instead. Practitioners on Reddit frequently report frustration with track-by-reference failing, and the missing account number is almost always the reason.
For small business owners who ship regularly, FedEx InSight offers a more powerful alternative. It’s a free tool that lets you proactively monitor all inbound and outbound shipments using reference numbers, without entering tracking numbers at all. Large shippers and government agencies particularly benefit from this, as they can search by PO numbers or Transportation Control Numbers across their entire shipping volume.
Practical Use Cases for FedEx Reference Numbers
Reference numbers become genuinely valuable once you ship more than a handful of packages. Here’s how different types of shippers use them:
E-commerce sellers enter the marketplace order number (Etsy, eBay, Shopify order ID) as the customer reference. When a buyer emails asking “where’s my package?”, the seller searches by that order number instead of digging through spreadsheets for a tracking number.
B2B wholesalers use PO numbers so receiving departments can match deliveries to open purchase orders without any phone calls or email chains.
Multi-department companies assign department codes to allocate shipping costs accurately. When the monthly FedEx invoice arrives, finance can sort charges by department instantly.
Returns operations use RMA numbers to connect incoming returns to specific customer service cases, speeding up refund processing.
If you’re evaluating whether FedEx or UPS better fits these workflows, our FedEx vs. UPS comparison covers pricing, service levels, and feature differences side by side.
Reference Numbers Across Carriers
FedEx isn’t the only carrier that supports reference numbers. This is a standard feature across major carriers, though the specifics vary:
| Carrier | Character Limit | Reference Fields Supported |
|---|---|---|
| FedEx | 50 characters | 2 per label |
| UPS | 35 characters | Up to 5 per shipment |
| USPS | 30 characters | 1 per label |
UPS actually offers more reference fields per shipment, which can matter for complex B2B shipping where you need to encode multiple identifiers on a single package.
Data Retention: How Long FedEx Keeps Reference Data
FedEx retains tracking information for 90 days after delivery for most services. After that, the tracking page goes blank. But here’s why reference numbers still matter beyond that window: they create a permanent link in your own records. When you enter “PO-2025-04821” as a reference, that connection between your purchase order and the shipment lives in your accounting software, your shipping platform, and your FedEx invoices forever (or as long as you keep those records).
This is particularly important for businesses that need to resolve disputes or audit shipping costs months after delivery. If you’re looking to understand and reduce those costs, our shipping cost calculator lets you compare rates across FedEx, UPS, USPS, and other carriers before you ship.
Frequently Asked Questions
Can recipients see the FedEx reference number?
Yes. The reference number is printed on the shipping label, so anyone handling or receiving the package can see it. However, shippers don’t always communicate the reference number to recipients directly, since it’s primarily meant for the shipper’s internal use.
Is a FedEx reference number required?
No. It’s completely optional. Every FedEx shipment gets a tracking number automatically, but reference numbers are only added if the shipper chooses to include one.
What if track-by-reference returns no results?
The most common cause is a missing or incorrect FedEx account number. You need the sender’s account number (not yours) to search by reference. Also double-check the ship date range and destination postal code. If it still doesn’t work, ask the sender for the actual tracking number.
How many characters can a FedEx reference number be?
Up to 50 alphanumeric characters. There are no format restrictions, so you can use letters, numbers, and hyphens in whatever pattern fits your business.
Do other carriers support reference numbers too?
Yes. UPS supports up to five reference numbers per shipment (35 characters each), and USPS supports one reference field per label (30 characters). Most shipping software platforms populate these fields automatically across all carriers.
Can two shipments have the same reference number?
Yes. Unlike tracking numbers, reference numbers are not globally unique. If you use the same PO number for multiple shipments (say, a split order shipped in two boxes), both will share that reference. This is actually useful, since searching by that reference will return all related packages at once.
How is FedEx InSight different from track-by-reference?
Track-by-reference is a one-time search on fedex.com. FedEx InSight is a free monitoring tool that continuously watches all shipments tied to your account and sends automatic status notifications. It’s designed for high-volume shippers who need to manage hundreds or thousands of packages without looking up each one individually.
Where should I enter reference numbers when shipping?
In FedEx Ship Manager, you’ll find the reference fields under package details when creating a shipment. Third-party platforms like Shippo and ShipStation have dedicated reference fields in their shipment creation forms. If you’re comparing options before committing to a shipping workflow, check current rates across carriers to find the best fit for your volume.