Lithium Battery Shipping to the US: DOT and UN38.3

What US rules apply to lithium battery shipping, and what Amazon asks for

Brands that sell devices with batteries often ask us:

"Our factory says the battery passed testing. Is that enough to ship to the US?"

"Our product has the battery inside. Which UN number is that?"

"Amazon put our listing on hold for a hazmat review. What do they want?"

The short answer: lithium batteries generally must be a type that passed UN 38.3. Manufacturers and distributors must make the test summary available. Air shipments add rules that depend on the battery and packaging.

UN 38.3 is a set of design tests in the UN Manual of Tests and Criteria, Part III, sub-section 38.3. In the US, the rule that requires it is 49 CFR 173.185, enforced by PHMSA, the Department of Transportation's hazardous materials agency.

1. Which UN number fits your product: UN3480, UN3481, UN3090 or UN3091

The UN number depends on two things: the battery chemistry and how the battery travels with the product. PHMSA's Lithium Battery Guide for Shippers lists four entries:

Lithium ion batteries are rechargeable and contain no metallic lithium.
Lithium metal batteries contain metallic lithium and are usually not rechargeable.
"Packed with equipment" means the battery is in the same box as the device but not installed.
"Contained in equipment" means the battery is installed in the device.

How the battery ships	Lithium ion	Lithium metal	What changes by air
By itself	UN3480	UN3090	Check aircraft and packing limits for the battery type (FAA)
Packed with equipment	UN3481	UN3091	Charge and packing limits depend on chemistry and size (FAA)
Contained in equipment	UN3481	UN3091	Different packing instructions apply (FAA)

A Bluetooth speaker with a built-in rechargeable battery is, for example, UN3481 contained in equipment. The same speaker sold with a loose spare battery in the box is UN3481 packed with equipment. A box of spare batteries alone is UN3480.

Get the UN number right first. Every limit after this depends on it.

2. The UN38.3 test summary: who needs one and what it must list

Lithium cells and batteries generally must be of a type proven to meet UN 38.3 (49 CFR 173.185). The test proves the design. The summary records the test.

Two dates matter, and they cover different points:

Batteries made on or after January 1, 2008: each manufacturer and subsequent distributor must make a test summary available, except for button cells installed in equipment (49 CFR 173.185(a)(3)).
January 21, 2022: PHMSA says manufacturers must provide it on request from this date (PHMSA).

The rule lists 10 required elements. They include the test lab, the test report number, the Wh rating or lithium content, the list of tests with pass or fail results, and the name of a responsible person (49 CFR 173.185(a)(3)).

The manufacturer must also keep the test record "for as long as that design is offered for transportation and for one year thereafter" (49 CFR 173.185(a)(2)).

A short statement from the factory is not a test summary. In interpretation 22-0007, PHMSA wrote that a shipper can rely on the manufacturer's information as evidence of testing, "but this would not meet the requirement for a manufacturer or distributor to make available a test summary." In interpretation 22-0044, PHMSA gave the same answer for a product summary that lacks the required elements.

PHMSA's 22-0044 answer applied this to a retailer or distributor. Ask the battery maker for the full document before the first shipment, and check it against the 10 elements.

A shipper may rely on manufacturer evidence, but manufacturers and distributors must make the required summary available.

3. Marking: the Wh rating and the lithium battery mark

Since May 10, 2024, "each lithium ion battery must be marked with the Watt-hour rating on the outside case" (49 CFR 173.185(a)(5)). Wh, or watt-hour, is the battery's energy rating.

The rule also sets size limits for small cells and batteries (49 CFR 173.185(c)):

Lithium ion: 20 Wh or less per cell, 100 Wh or less per battery
Lithium metal: 1 g of lithium or less per cell, 2 g or less per battery

Batteries within these limits fall under the section (c) provisions for smaller cells and batteries.

Packages under these provisions carry the lithium battery mark. Under 49 CFR 173.185(c)(3)(ii), the mark in effect on May 9, 2024 "may continue to be used until December 31, 2026."

Check the Wh rating on the case and the mark version on the carton before December 31, 2026.

4. Shipping lithium batteries by air: charge, aircraft and package limits

Air limits depend on chemistry, watt-hours and whether the battery is loose, packed with equipment or installed. The FAA's 2026 guide separates those cases. For example, certain lithium-ion batteries packed with equipment above 2.7 Wh must be at 30% charge or less under the guide's international air instructions.

For small batteries packed with equipment by air, the US rule also caps the package. The lithium cells or batteries in the completed package must not exceed 5 kg net, and the count is limited to "the minimum number required to power the piece of equipment, plus two spare sets" (49 CFR 173.185).

Some air shipments require a dangerous goods declaration. PHMSA warns that noncompliance may result in fines or criminal prosecution (PHMSA).

Carriers can set stricter rules and can refuse a shipment that meets 49 CFR and IATA. Ask your forwarder for the airline's rules.

Before air shipment, confirm the applicable packing instruction and airline rules.

5. Ocean and domestic parcels follow other rules

Ocean freight follows the IMDG Code, the International Maritime Organization's dangerous goods code, not the IATA rules. A 2026 industry shipping guide from Currie Associates points ocean shippers of UN3480 to IMDG Amendment 42-24.

Inside the US, parcel carriers such as USPS, UPS and FedEx each publish their own battery rules for ground and parcel shipping. Those carrier rules sit on top of 49 CFR. Check the carrier's battery page before you ship orders to customers.

Ocean entries still go through US customs like any other import. Our US customs clearance guide covers the importer of record and the entry process.

Check UN 38.3 test information for each mode. Air has additional packing rules.

6. Amazon FBA: what the hazmat review asks for

Amazon may request battery and hazardous-goods documents during listing or FBA review. Check its current battery requirements and hazmat documentation before listing.

Our FBA vs 3PL comparison covers the fulfillment choices.

Five checks before your first lithium battery shipment

1. Is the UN number set: UN3480, UN3481, UN3090 or UN3091?

2. Can the manufacturer provide the required UN38.3 test information?

3. Is the Wh rating on the battery case, and which version of the lithium battery mark is on the carton?

4. For air, have you checked the packing instruction and charge limit for this battery?

5. For Amazon, have you checked the current document requirements?

Battery products also carry product safety risk after sale. Our product liability insurance guide covers what US retailers and platforms expect.

Wrap-up

Lithium battery shipping starts with the UN number and test information. Check the applicable packing and charge rules for each mode.

LinkONE runs Korea to USA ocean and air freight as an FMC-registered NVOCC, and offers import compliance consulting and Amazon FBA prep from its Fullerton, California warehouse.

Confirm the battery's test information and the carrier's requirements before shipment.

Frequently Asked Questions

What is UN38.3?

UN38.3 is the UN design test for lithium cells and batteries, in Part III, sub-section 38.3 of the UN Manual of Tests and Criteria. Under 49 CFR 173.185, each lithium cell or battery shipped in the US must be of a type proven to meet it.

Do I need a test summary if the manufacturer says the battery is tested?

PHMSA says a shipper may rely on manufacturer information as evidence of testing. Manufacturers and distributors must make the required test summary available (PHMSA).

Is my product UN3480 or UN3481?

UN3480 covers lithium ion batteries shipped by themselves. UN3481 covers lithium ion batteries packed with or contained in equipment (PHMSA Lithium Battery Guide). For lithium metal batteries, the matching numbers are UN3090 and UN3091.

What state of charge do I need for shipping lithium batteries by air?

It depends on the chemistry, size and packing configuration. Check the FAA guide and your airline's rules.

How long does Amazon's hazmat review take?

Check the current review and document requirements in Amazon Seller Central.

Sources

Fees and rules in this post are as of October 2026.

-LinkONE-