FedEx Box Sizes: One Rate Box, Pak and Envelope Dimensions
FedEx gives Express shippers nine free box sizes. The most used are the Small Box S1 at 12 3/8 x 10 7/8 x 1 1/2 inches, the Medium Box M1 at 13 1/4 x 11 1/2 x 2 3/8, the Large Box L1 at 17 1/2 x 12 3/8 x 3 and the Extra Large Box X1 at 11 7/8 x 11 1/16 x 10 13/16. With One Rate, any of them ships at one price up to 50 lb. They are for FedEx Express services only: FedEx says its free packaging cannot be used for FedEx Ground or Home Delivery, so Ground shipments need your own box. The last column lists a stocked box that holds the same contents.
FedEx box sizes
| Box | Code | Inside size | FedEx recommended max | Shape | Own box for Ground |
|---|---|---|---|---|---|
| Extra Small Box | 7 1/4 x 4 11/16 x 2 1/2 | Not published | Added February 2, 2026; size stated by FedEx without an inside or outside label | 8 x 5 x 3 | |
| Small Box | S1 | 12 3/8 x 10 7/8 x 1 1/2 | 20 lb | Shallow: documents, flat goods | 13 x 11 x 2 |
| Small Box | S2 | 11 5/16 x 8 3/4 x 2 11/16 | 20 lb | Deeper small box | 12 x 9 x 3 |
| Medium Box | M1 | 13 1/4 x 11 1/2 x 2 3/8 | 20 lb | Shallow medium | 14 x 12 x 3 |
| Medium Box | M2 | 11 5/16 x 8 3/4 x 4 3/8 | 20 lb | Deeper medium | 11.75 x 8.75 x 4.75 |
| Large Box | L1 | 17 1/2 x 12 3/8 x 3 | 30 lb | Long and shallow | 20 x 14 x 3 |
| Large Box | L2 | 11 5/16 x 8 3/4 x 7 3/4 | 30 lb | Square and deep | 12 x 9 x 8 |
| Extra Large Box | X1 | 11 7/8 x 11 1/16 x 10 13/16 | 50 lb | Cube shaped | 12 x 12 x 11 |
| Extra Large Box | X2 | 15 3/4 x 14 3/16 x 6 | 50 lb | Wide and shallow | 16 x 16 x 6 |
The FedEx One Rate page rounds some of these sizes, for example 11 1/4 instead of 11 5/16 inches, so the two FedEx sources differ by up to 1/16 inch. The table uses the inside dimensions from the FedEx packaging guide. FedEx recommends lighter contents than the One Rate maximum for the smaller boxes: 20 lb in the Small and Medium boxes and the Tube, 30 lb in the Large boxes.
FedEx envelope, pak and tube sizes
| Packaging | Size | One Rate max weight |
|---|---|---|
| FedEx Envelope | 9 1/2 x 12 1/2 | 10 lb |
| Legal Size Reusable Envelope | 9 1/2 x 15 1/2 | 10 lb |
| Padded Envelope | 9 3/4 x 11 1/2 | 10 lb |
| Small Pak | 10 1/4 x 12 3/4 | 50 lb |
| Large Pak | 12 x 15 1/2 | 50 lb |
| Padded Pak | 11 3/4 x 14 3/4 | 50 lb |
| Reusable Sturdy Pak | 10 x 14 1/2, expands 1 1/2 | 50 lb |
| FedEx Tube | 6 x 6 x 38 triangular | 50 lb |
FedEx also offers a 10kg Box, 15 13/16 x 12 15/16 x 10 3/16 inches, and a 25kg Box, 21 9/16 x 16 9/16 x 13 3/16 inches, for exports by FedEx International Priority and International Priority Express only.
FedEx One Rate rules
- One Rate requires FedEx packaging and a FedEx Express US service: First Overnight, Priority Overnight, Standard Overnight, 2Day A.M., 2Day or Express Saver.
- Envelopes must weigh 10 lb or less; paks, boxes and tubes 50 lb or less.
- An envelope thicker than 3 inches or a pak thicker than 5 inches at its shortest side is rated as a One Rate box.
- One Rate is not available for FedEx Ground or for international shipments.
- Outside One Rate, FedEx boxes carry a 2 lb minimum billable weight and the Tube 9 lb, and FedEx may apply dimensional weight to its own packaging.
Shipping FedEx Ground? Use your own box
Free FedEx boxes cannot ship by FedEx Ground or Home Delivery. For Ground, use a plain corrugated box and pay by weight or dimensional weight. Each box in the last column of the table is the smallest stocked 32 ECT box whose inside dimensions are at least as large as the FedEx box, so anything that fits the FedEx box fits it. Check the price per package with the dimensional weight calculator.
Frequently asked questions
What are the FedEx One Rate box sizes?
Small S1 12 3/8 x 10 7/8 x 1 1/2 in and S2 11 5/16 x 8 3/4 x 2 11/16 in; Medium M1 13 1/4 x 11 1/2 x 2 3/8 in and M2 11 5/16 x 8 3/4 x 4 3/8 in; Large L1 17 1/2 x 12 3/8 x 3 in and L2 11 5/16 x 8 3/4 x 7 3/4 in; Extra Large X1 11 7/8 x 11 1/16 x 10 13/16 in and X2 15 3/4 x 14 3/16 x 6 in; and the Extra Small Box 7 1/4 x 4 11/16 x 2 1/2 in.
Can I use a FedEx box for FedEx Ground?
No. FedEx says its complimentary packaging cannot be used for FedEx Ground or FedEx Home Delivery. Use your own box for Ground shipments.
How much weight can a FedEx One Rate box hold?
Up to 50 lb under One Rate. FedEx recommends no more than 20 lb in the Small and Medium boxes and the Tube, and 30 lb in the Large boxes.
What is the largest FedEx box?
For domestic shipping, the Extra Large X1 at 11 7/8 x 11 1/16 x 10 13/16 inches holds the most volume. The 25kg Box is larger but is only for international exports.
Are FedEx boxes free?
Yes. FedEx supplies its branded boxes, paks, tubes and envelopes free for FedEx Express shipments.
What size is the FedEx Small Box?
The S1 is 12 3/8 x 10 7/8 x 1 1/2 inches inside and the S2 is 11 5/16 x 8 3/4 x 2 11/16 inches.
Related tools and charts
- UPS box sizes
- USPS Priority Mail box sizes
- USPS flat rate box sizes and prices
- USPS, UPS and FedEx size and weight limits
- Box size chart
- Mailing tube size chart and poster tube finder
Sources: FedEx packaging guide for Express supplies, FedEx One Rate page and the 2026 FedEx Service Guide, checked October 26, 2026. FedEx is a trademark of FedEx Corporation; Packrift is not affiliated with FedEx.