dgdataapi.com · August 2026
Ask most e-commerce sellers about lithium battery shipping and you'll hear the same number: 100 watt-hours. Under 100 Wh, small-battery rules; over it, full dangerous goods treatment. That's the number printed on airline placards and repeated in every forum thread.
It's also incomplete. For US ground shipping (highway and rail), the federal regulations allow lithium ion batteries up to 300 Wh to ship under the smaller-battery exception. No shipping papers, no Class 9 label, no hazmat-trained staff. The catch is one specific package marking and a few packaging conditions, and the whole thing lives in one paragraph of the regulations that most people never read: 49 CFR §173.185(c)(1)(iv).
| Base exception (any mode) | Ground-only extension (highway/rail) | |
|---|---|---|
| Lithium ion cell | ≤ 20 Wh | ≤ 60 Wh |
| Lithium ion battery | ≤ 100 Wh | ≤ 300 Wh |
| Lithium metal cell | ≤ 1 g lithium | ≤ 5 g |
| Lithium metal battery | ≤ 2 g lithium | ≤ 25 g |
| Citation | §173.185(c)(1)(i)-(ii) | §173.185(c)(1)(iv) |
Note the cell vs. battery split. It matters more than people expect: a single-cell battery (a coin cell, or many power banks) legally counts as a cell under §173.185(a)(1), so it uses the lower cell limits. A "50 Wh battery" that's actually one big cell is over the 20 Wh base cell limit even though it's far under 100.
To use the 300 Wh tier by highway or rail, §173.185(c)(1)(iv) requires the outer package to be marked:
"LITHIUM BATTERIES—FORBIDDEN FOR TRANSPORT ABOARD AIRCRAFT AND VESSEL"
with minimum letter heights set by (c)(1)(v). That marking is the trade: you get the higher limits precisely because the package can never be handed to a plane or a ship. The rest of the smaller-battery conditions still apply: inner packagings that fully enclose each battery, a strong rigid outer package, the 1.2 meter drop test, the lithium battery mark with the UN number (with narrow exemptions for small consignments contained in equipment), and the watt-hour rating marked on each battery's case.
Here's the part that keeps this from being a free lunch. 49 CFR is the federal floor. Individual carriers layer their own rules on top, and those are often stricter: UPS and FedEx Ground both run their own dangerous goods programs with their own acceptance conditions, and USPS Publication 52 is more restrictive than the federal regulations across the board. A package that's perfectly legal under §173.185(c)(1)(iv) can still be refused at the counter under a carrier's tariff.
So the honest version of the rule is: the 300 Wh ground tier is a federal allowance that makes a shipment legally possible, and your carrier's dangerous goods program decides whether it's practically accepted. Check both, in that order.
I maintain a free classifier for exactly this question. Give it the chemistry, watt-hours, and packing configuration, and it returns the status with the regulation citations attached:
Try it on the homepage, or hit the API directly:
https://api.dgdataapi.com/v1/lithium-batteries/classify?chemistry=ion&unit=battery&watt_hours=250&configuration=with_equipment
This article is reference information derived from 49 CFR as of the August 2026 amendments, not legal or transportation advice; verify against the current eCFR text and your carrier before shipping. Corrections welcome: hello@dgdataapi.com.