Most flights allow up to 100 Wh in carry-on; 101–160 Wh needs airline approval, and anything above 160 Wh isn’t allowed.
Here’s the short version you came for: power banks ride in your cabin bag only. The safe zone is up to 100 watt-hours (Wh). Packs between 101 and 160 Wh can fly when your airline says yes, and you’re usually limited to two of them. Bigger than that doesn’t board. The sections below show you how to read your label, convert mAh to Wh, and pass check-in without drama.
Allowed Power Bank Size For Flights: Rules That Matter
Air safety rules treat a power bank as a spare lithium battery. That means carry-on, terminals covered, and no charging while it’s stowed. The strict part is capacity. Aviation regulators set the main threshold at 100 Wh. Packs at or under 100 Wh are generally fine in your cabin bag. Between 101 and 160 Wh you need airline approval, and there’s a two-unit cap in most policies. Anything over 160 Wh is barred from passenger cabins.
Quick Limits At A Glance
Use this table as your first pass when packing. It reflects standard passenger rules used by airlines and regulators.
| Battery Size (Wh) | Where It Can Go | How Many |
|---|---|---|
| 0–100 Wh | Carry-on only | Commonly allowed (check airline if carrying many) |
| 101–160 Wh | Carry-on only, airline approval required | Usually up to two spares per traveler |
| >160 Wh | Not allowed on passenger flights | None |
Why the focus on Wh? Watt-hours tell the cabin crew the stored energy regardless of voltage. That’s the figure regulators use to set limits, and it’s often printed right on the label. When it isn’t, you can convert from mAh in seconds. Keep reading for the formula and worked examples so you can decode any pack you own.
How To Read Labels And Convert mAh To Wh
Many brands list capacity in milliamp-hours (mAh) because shoppers recognize that number. Airlines care about Wh. The math is straightforward:
Wh = (mAh × V) ÷ 1000
Most small packs use a 3.6–3.85 V cell. Manufacturers typically round to 3.7 V for marketing. If your label shows only mAh, assume 3.7 V unless the spec says otherwise. Two quick examples:
- 10,000 mAh at 3.7 V → (10,000 × 3.7) ÷ 1000 = 37 Wh (well under 100 Wh)
- 27,000 mAh at 3.7 V → (27,000 × 3.7) ÷ 1000 = 99.9 Wh (just under the line)
If your label lists “nominal energy” already (e.g., “Energy: 74 Wh”), you’re done—use that number. If it shows multiple outputs (USB-A, USB-C, PD), those are charging voltages and don’t change the Wh on the label.
Label Must-Haves That Help At Security
- The energy rating in Wh, or capacity in mAh and nominal voltage.
- Model number and brand.
- Visible terminals or ports that can be covered or switched off.
Packs without clear specs can slow your screening. If yours lacks a label, carry the box or a spec sheet screenshot. It saves time when a gate agent asks.
Carry-On Only: Why Checked Bags Are Off-Limits
Spare lithium batteries belong in the cabin because crews can spot and handle a smoke event quickly. Cargo holds aren’t set up for that. So your charger lives in your personal item or backpack, never in a checked suitcase. If you gate-check a bag, pull the pack out before handing it over.
Simple Packing Steps That Pass Every Time
- Cover exposed terminals with a cap or tape. Many cases do this already.
- Use a soft pouch to prevent pressure on buttons that could turn it on.
- Keep the pack separate from metal items that could short the ports.
- Charge it at home; many carriers don’t allow charging a power bank during the flight.
When You Need Airline Approval
If your pack sits between 101 and 160 Wh, contact the carrier before you fly. Approval is usually fast when the pack is clearly labeled and in good condition. Expect a limit of two spares per traveler in that range. Some carriers add extra packaging rules, like taping ports or placing the pack in its own sleeve. Ask for the notation to be added to your booking so check-in staff can see it.
What Airline Staff Look For
- Clear Wh rating at 160 Wh or below.
- No swelling, dents, or damaged casing.
- Ports covered and the unit powered off.
- Reasonable quantity for a personal trip.
Common Scenarios With Real Numbers
Phone-Sized Packs
5,000–10,000 mAh units land around 18.5–37 Wh at 3.7 V. These sail through screening and sit well under the 100 Wh threshold.
Travel Laptop Chargers
20,000–26,800 mAh units often land near 74–99 Wh. They’re popular because they power a USB-C laptop and still meet the easiest rule set. If you’re close to 100 Wh, keep the label handy in case the agent asks.
Large Packs For Cameras Or Gaming
30,000–43,000 mAh models can cross into the approval zone. At 3.7 V, 30,000 mAh is 111 Wh, and 43,000 mAh is about 159 Wh. That fits the approval-needed bracket and the two-spare cap. Anything beyond that range doesn’t fly with passengers.
Regional Notes And Where The Rules Come From
Airlines follow a shared playbook for passenger safety. In the United States, the cabin rules for spare lithium batteries live in federal guidance used by carriers and screeners. Internationally, the same approach appears in industry standards. Two links worth saving:
Both sources treat a power bank as a spare battery, set the 100 Wh baseline, require airline approval in the 101–160 Wh band, and bar larger units from passenger cabins.
How Many Power Banks Can You Bring?
There isn’t a single global number for tiny packs under 100 Wh. Carriers focus on reasonable personal use. Tech travelers often bring two or three small units with no trouble. The only hard cap that shows up across policies is in the 101–160 Wh bracket: up to two spares, with approval. If you carry a pile of small units for a shoot or event, let the airline know in advance so staff aren’t surprised at screening.
What About Built-In Batteries In Luggage Or Gadgets?
Smart suitcases with removable batteries must have the pack taken out and carried in the cabin. Gear with installed batteries—laptops, cameras, tablets—can ride in your cabin bag, and sometimes in a checked bag when fully switched off, but the spare battery rule still applies. A standalone charger never goes in checked luggage.
When Your Label Uses mAh Only
Many packs still print “mAh” in big type. Use the formula to translate to Wh before you fly. If the math lands you near a threshold, print a small card with the calculation. It helps during a quick bag check.
mAh-To-Wh Cheat Sheet
| Rated Capacity | Assumed Voltage | Energy (Wh) |
|---|---|---|
| 5,000 mAh | 3.7 V | 18.5 Wh |
| 10,000 mAh | 3.7 V | 37 Wh |
| 20,000 mAh | 3.7 V | 74 Wh |
| 26,800 mAh | 3.7 V | 99 Wh |
| 30,000 mAh | 3.7 V | 111 Wh |
| 40,000 mAh | 3.7 V | 148 Wh |
| 43,000 mAh | 3.7 V | 159 Wh |
Condition And Quality Checks Before You Pack
Screeners look at capacity first, then condition. A scuffed corner isn’t a problem; swelling and heat marks are. If a pack looks damaged, leave it at home. Buy from known brands with clear labels and built-in protections like over-current shutoff and thermal cutout. Cheap packs with inflated mAh claims trigger the most headaches at the checkpoint.
Quick Answers To Edge Cases
Can You Bring Two Laptop-Class Packs?
Yes when each is under 100 Wh. If both are 101–160 Wh, you’re in the approval zone and capped at two spares in total.
Can You Use The Pack During The Flight?
Many carriers say no to charging a stand-alone pack while seated, even if using your own cable. Charging a phone from the pack is usually fine. Crew instructions win every time, so ask if you’re unsure.
Do Airlines Care About Total Wh Across Multiple Units?
Policies track per-unit energy, not the sum across your bag. Staff still watch for excess. A dozen tiny packs for a short trip can raise eyebrows, even if each unit is under 100 Wh.
Step-By-Step Packing Checklist
- Find the Wh on the label. If missing, convert from mAh using 3.7 V.
- Stay at or under 100 Wh when you can. If you’re in the 101–160 Wh range, request approval and carry only two spares.
- Place the pack in your personal item with ports covered.
- Keep the pack off during takeoff and landing, and anytime crew asks.
- Carry proof of specs: photo of the label or a spec sheet link.
Real-World Picks That Fit The Rules
The sweet spot for travel is a 20,000–26,800 mAh unit at 3.7 V. You’ll charge a phone several times, top up a tablet, and even feed a compact laptop, all while staying below the 100 Wh line. If you film on mirrorless bodies or game on the go, a 30,000–43,000 mAh pack can make sense, but plan for airline approval. Anything marketed for camping with DC outputs and huge mAh numbers usually breaks the 160 Wh barrier; leave that at home or ship it by ground.
What To Do If A Gate Agent Questions Your Pack
Stay calm and show the label. Point to the Wh figure or your mAh-to-Wh math. If you’re in the approval zone, show the note in your booking or the email from the airline. Offer to keep the pack powered off and isolated in your personal item. Clear labeling and a polite explanation settle most checks in under a minute.
Save These Two Links
Rules update from time to time. These pages keep current and match what agents quote at the counter:
Bottom Line For Smooth Screening
Pick a pack labeled under 100 Wh when you can. Keep spares in your cabin bag with ports covered. Ask for approval if your unit sits between 101 and 160 Wh, and bring no more than two in that range. Anything bigger stays home. With those steps, your charger breezes through security and your devices land with power to spare.