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Your 20,000mAh power bank is allowed in carry-on on nearly every airline. At the standard 3.7V nominal voltage, that rating converts to about 74Wh, which sits under the 100Wh threshold that needs no airline approval.
But the capacity number alone is not the whole story. A worn or missing watt-hour label can get the same device confiscated at screening, and several Asia-Pacific carriers ban using a power bank to charge a phone in flight even when the unit itself is cleared to fly.
The power bank in your bag says 20,000mAh. The security officer at the checkpoint does not care about that number. Neither, in a different way, does the flight crew.
Aviation rules run on watt-hours, printed labels, and a patchwork of carrier policies. A device can clear the capacity threshold and still be confiscated because its label is unreadable. Or it can be allowed on board and still be banned from use mid-flight.
The global baseline tightened in March 2026 with a two-unit cap and a no-recharging rule, but carrier-level differences on using a power bank to charge a phone remain largely unresolved. This piece works backwards from enforcement reality: thresholds first, then the failure points that actually cost travelers a device or an in-flight battery strategy.
The number on the casing isn’t the number being enforced
Power bank casings advertise capacity in milliampere-hours because that is the number buyers recognize. Enforcement runs on a different unit: watt-hours, which measures energy rather than charge.
The conversion your airline will not do for you is mAh × nominal cell voltage ÷ 1,000. For nearly all consumer power banks, the nominal voltage is 3.7V. A 20,000mAh unit is therefore 74Wh; a 10,000mAh unit is about 37Wh.
This is the math the International Air Transport Association (IATA) uses in its power bank guidance — and it is the number screeners and gate agents actually enforce.
| mAh rating | Calculated Wh at 3.7V | Regulatory tier |
|---|---|---|
| 5,000 | 18.5 | ≤100Wh no approval |
| 10,000 | 37.0 | ≤100Wh no approval |
| 15,000 | 55.5 | ≤100Wh no approval |
| 20,000 | 74.0 | ≤100Wh no approval |
| 26,800 | 99.2 | ≤100Wh no approval |
| 30,000 | 111.0 | 101–160Wh written airline approval, two-unit cap |
| 40,000 | 148.0 | 101–160Wh written airline approval, two-unit cap |
| 50,000 | 185.0 | >160Wh prohibited |
| 60,000 | 222.0 | >160Wh prohibited |
| Source: International Air Transport Association (IATA); Singapore Airlines | ||
The 3.7V figure is the nominal cell voltage used in the conversions shown by IATA and Singapore Airlines guidance. The calculation changes only if a device uses a different nominal voltage, and no alternate common consumer voltage was verified for this piece. All values are rounded to one decimal place.
The table assumes the rating printed on the casing is legible. It is not always. Screeners can seize a power bank whose watt-hour specification is unreadable or missing, because they cannot verify compliance — even when the unit is, in fact, under the 100Wh threshold.
What proof can stand in for a worn label is not established in the guidance checked for this piece. No source confirmed whether a manufacturer spec sheet, a photo of the original packaging, or a receipt will be accepted. Treat the printed Wh rating as the only reliable proof a checkpoint will accept.
The three capacity tiers, and the 30,000mAh test case
The watt-hour figure splits devices into three tiers. Up to and including 100Wh needs no airline approval.
The approval band runs from 101Wh to 160Wh, and above that ceiling a device cannot fly on a passenger aircraft at all.
A 30,000mAh power bank is where the approval tier bites. At 3.7V it works out to 111Wh, just over the no-approval ceiling.
That means written airline approval, requested in advance, is not optional. Singapore Airlines’ process shows what that looks like: its own form, a photo of the unit, the voltage and power ratings, and documentary proof the unit passed UN 38.3 testing. Manufacturer marketing material does not count.
The upper boundary is even simpler. A 50,000mAh unit converts to about 185Wh, above the 160Wh ceiling. That is a flat no on every passenger carrier, no matter the approval paperwork.
The worldwide two-unit cap that took effect in March 2026 matters most in this band. It is not clear, though, whether that cap resets per flight segment or applies once across an entire journey. Multi-leg travelers should check before assuming.
The 100Wh and 160Wh thresholds come from the same ICAO/IATA baseline that applies worldwide, so the math does not change by carrier. What does change is in-flight usage: the mid-flight charging bans now common on Asia-Pacific routes are not uniform across carriers, so a device may be allowed aboard while its in-flight use rule differs. Check the carrier either way.
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The question no one separates: use, or recharge?
Two different acts get collapsed into one in most airline policy pages: using a power bank to charge a phone or laptop, and recharging the power bank itself. Carriers do not treat them identically. Travelers who confuse the two either surrender a permitted device or misuse a prohibited one.
The March 2026 baseline draws the line with two verbs: power banks must not be recharged during flight, and they should not be used to recharge a portable electronic device. The first is a flat ban in the baseline itself. The second is softer language that some carriers have turned into an outright prohibition.
Across the verified Asia-Pacific pages, the trend is strict. Cathay Pacific and Singapore Airlines each prohibit using a power bank to top up another device onboard, and both bar recharging the power bank itself.
Incheon Airport‘s carry-on guidance separately prohibits both directions — charging a phone from a power bank, and charging the power bank itself. Cathay Pacific also warns that units beyond the two-power-bank limit will be confiscated by screeners at Hong Kong International Airport.
The practical consequence for a multi-carrier itinerary is that the same device can face two enforcement points, since Singapore Airlines requires written sign-off for a 111Wh unit before boarding.
On Cathay Pacific, the published page emphasizes the two-unit cap instead. The global baseline did not flatten those differences.
The documentary backbone of the March 2026 change
The global baseline did not come from a press release. It sits in Addendum No. 1 to ICAO Doc 9284, the technical instructions for dangerous goods, applicable 27 March 2026 and mirrored in IATA’s guidance. A copy of that addendum is hosted by Philippine Airlines.
The addendum sets out three provisions: power banks are treated separately from spare batteries, each passenger is capped at two units, and recharging one in the air is banned. Together they form the baseline that national regulators and individual airlines build their own rules on.
It is also why so much traveler confusion remains. The addendum does not fully settle the separate question of using a power bank to charge a phone, and carriers fill that space differently.
What this means for you
Before you pack, run the watt-hour math or check the table above against your unit’s mAh rating. Then check the carrier’s battery page carefully, since it settles two distinct issues: whether the unit is allowed on board at all, and whether it can legally be used to charge another device once the aircraft is airborne.
For any unit in the 100Wh-to-160Wh band, arrange the written approval evidence the carrier demands before you reach the airport. A worn label is a separate risk: carry a photo of the device, its spec sheet, or your approval paperwork, and accept that screeners may still refuse any of it.
Key terms
- Watt-hour (Wh)
- A watt-hour is a unit of energy equal to one watt of power sustained for one hour. Aviation rules use it, rather than milliampere-hours, to set power bank limits because it measures total energy instead of charge. Because the 100Wh and 160Wh thresholds are written in watt-hours, whether a given device complies depends on a conversion most travelers have never done.
- mAh (milliampere-hour)
- A milliampere-hour is a unit of electric charge, equal to one thousandth of an ampere flowing for one hour. Power bank casings advertise capacity in mAh because it is the number buyers recognize, but it is not the unit regulators enforce. Converting mAh to watt-hours means multiplying by the cell’s nominal voltage and dividing by 1,000 — a step the airline will not do for you at the checkpoint.
- ICAO Doc 9284
- ICAO Doc 9284 is the International Civil Aviation Organization’s technical instructions for the safe transport of dangerous goods by air. It sets the international standards that airlines and national regulators build their own dangerous goods rules on. Its Addendum No. 1, applicable 27 March 2026, is where the current power bank provisions originate, which is why carriers cite the same addendum language.
- UN 38.3
- UN 38.3 is a United Nations test standard for lithium batteries shipped as dangerous goods. It is the compliance benchmark airlines cite when they require proof that a battery has been tested for transport. For a power bank in the approval band, carriers may ask for documentary proof of UN 38.3 compliance as part of the written sign-off process.
Questions? Answers.
Can I bring a 30000mAh powerbank on a plane?
A 30,000mAh power bank converts to about 111Wh at 3.7V, which falls inside the 100Wh-to-160Wh band. That tier requires prior written airline approval, and the worldwide two-unit per passenger cap applies.
What power banks are not allowed on planes?
Power banks above 160Wh are not allowed on passenger aircraft. At 3.7V, a 50,000mAh unit is about 185Wh and a 60,000mAh unit is about 222Wh — both above the ceiling and barred regardless of airline.
Can I take a 20000mAh power bank on a plane?
Yes. A 20,000mAh power bank converts to about 74Wh at 3.7V, which sits under the 100Wh ceiling that needs no airline approval.
Can I carry a 3 power bank in flight?
No. The worldwide maximum under the March 2026 baseline is two power banks per passenger, and both Cathay Pacific and Incheon Airport guidance state the same two-per-person limit. A third unit exceeds the allowance.
Can I fly with two power banks?
Yes. Two power banks per person is the maximum allowance under the March 2026 ICAO/IATA baseline, and Cathay Pacific and Incheon Airport both publish the same two-unit cap.
Can I charge my phone from a power bank during a flight?
On many Asia-Pacific carriers, no. Singapore Airlines bans using or charging power banks for the entire flight, Cathay Pacific bans use and recharging onboard at any time, and Incheon Airport prohibits charging a smartphone from a power bank and charging the power bank itself. The March 2026 baseline also says power banks should not be used to charge another device in flight.
