Cabin baggage · Wizz Air and Ryanair · rules checked on 7 November 2026

Can I take this power bank on the plane?

The battery usually shows milliamp-hours, while airline rules are written in watt-hours. This tool converts with the voltage printed on the label and compares the result with the limit and the allowed number at the airline you choose. It is written for flights from Romania with Wizz Air and Ryanair, the two largest low-cost carriers at Romanian airports.

The scale runs to 160 Wh so the usual 100 Wh limit sits in context. The tick marks the limit; the fill shows the example battery, then yours.

The result for this battery

Example, before you enter your own battery

Meets the conditions

20,000 mAh at 3.7 V means 74 Wh: under the 100 Wh limit at Wizz Air.

20,000 × 3.7 / 1,000 = 74 Wh. One power bank, cabin only, under the seat or in the seat-back pocket, protected against short circuit. At Wizz Air a power bank must not be used or charged during the flight.

How are mAh converted into Wh for flying?#

The formula used by the UK Civil Aviation Authority, the British aviation regulator, is short: watt-hours equal milliamp-hours multiplied by the nominal cell voltage, divided by one thousand. The same 20,000 mAh battery holds 72 Wh at 3.6 V, 74 Wh at 3.7 V and 77 Wh at 3.85 V. That is why the mAh number alone settles nothing.

The voltage that matters belongs to the cell inside and is usually printed on the back, beside the capacity. The 5 V figure at the USB port describes the output towards the phone, after electronic conversion, and would inflate the sum if used in the formula. Some models print both values, for instance “20000mAh / 74Wh”; the Wh value is then the most direct evidence at the checkpoint.

Marking on the battery	At 3.6 V	At 3.7 V	At 3.85 V	Against 100 Wh
10,000 mAh	36 Wh	37 Wh	38.5 Wh	Under the limit at all three voltages
20,000 mAh	72 Wh	74 Wh	77 Wh	Under the limit at all three voltages
26,800 mAh	96.48 Wh	99.16 Wh	103.18 Wh	The voltage decides
30,000 mAh	108 Wh	111 Wh	115.5 Wh	Over the limit at all three voltages

The last two rows show why round advice such as “anything under 27,000 mAh is fine” needs the label in hand: at 26,800 mAh, the step from a 3.7 V cell to a 3.85 V cell moves the battery across the limit.

What do Wizz Air and Ryanair say about power banks?#

Both airlines start from the same 100 Wh limit for a power bank and differ on how many may travel and whether they may be used in flight. The table gives the rules as read on 7 November 2026.

The question	Wizz Air	Ryanair
Limit for one power bank	At most 100 Wh; power banks over 100 Wh are forbidden	At most 100 Wh; over 100 Wh, neither cabin nor hold
Power banks per person	One	Two, inside an overall limit of 20 spare lithium batteries
Where they travel	In the cabin, under the seat or in the seat-back pocket; overhead lockers are excluded	In the cabin, on the person or in the underseat bag; overhead lockers are excluded
Charging a phone from it in flight	Forbidden throughout the flight	Allowed outside taxi, take-off and landing, following crew instructions
Recharging the power bank on board	Forbidden	Forbidden
In checked baggage	Forbidden	Forbidden

The Wizz Air page also mentions a 100–160 Wh band with prior approval. That passage covers spare batteries and batteries in equipment, while for power banks the same page forbids anything over 100 Wh. This tool follows the power-bank rule. Travellers carrying camera or drone batteries should read those passages directly, since numbers and approvals differ.

Can I charge a phone from a power bank during the flight?#

The answer depends on the airline. At Wizz Air the power bank travels switched off: it charges no phone and is not itself charged at any stage of the flight. At Ryanair, charging personal devices from a power bank is allowed in cruise, with three moments excluded: taxi, take-off and landing, plus any moment when the crew says otherwise.

Both airlines keep the battery within reach, under the seat or in the seat pocket. The reason is supervision: a lithium battery that starts to heat up has to be noticed early. The British regulator puts the same point plainly: a battery that gets hot is switched off and the crew is told at once; smoke is reported without waiting.

Terminals and ports are protected against short circuit: the original packaging, a pouch or a separate bag for each battery meets the requirement both airlines state for spare batteries.

What still gets decided at the airport#

The tool compares three things: the energy computed from the marking, the 100 Wh limit, and the number of power banks the chosen airline allows. Everything else stays with the reader and the airport staff. A battery with no readable marking can be assessed by nobody on the spot, however exact the arithmetic at home.

The check above covers ordinary power banks for phones and tablets at Wizz Air and Ryanair, in the form read on 7 November 2026. Medical equipment, electric wheelchairs, drones and smart bags with non-removable batteries have their own passages on the airline pages. The departure airport may add its own security rules.

Rules on lithium batteries have tightened repeatedly in recent years. A one-minute check on the airline page on the day of travel remains part of packing, above all for a battery sitting near the limit.

Frequently asked questions#

Can I take a 20,000 mAh power bank on a plane?

At the usual cell voltages, 20,000 mAh means between 72 and 77 Wh, under the 100 Wh limit at both airlines in this tool. The conditions on number, place in the cabin and use still apply, and they differ between Wizz Air and Ryanair.

Can I take a 30,000 mAh power bank on a plane?

At 3.6–3.85 V, 30,000 mAh means between 108 and 115.5 Wh. That passes the 100 Wh limit, and Wizz Air and Ryanair do not accept power banks over it.

How many mAh does Wizz Air allow?

The airline page works in watt-hours: one power bank per person, of at most 100 Wh. In mAh the limit moves with voltage: 27,700 mAh reaches 99.72 Wh at 3.6 V, while the same marking passes 106 Wh at 3.85 V.

Can a power bank travel in checked baggage?

No. Both airlines require the cabin, within reach, under the seat or in the seat pocket. The British regulator gives the same reason: a battery overheating in the hold cannot be noticed and stopped in time.

What if nothing can be read on the battery any more?

The watt-hour value cannot be shown at the checkpoint, and staff may refuse the battery. The maker specification sheet, saved on the phone, helps the conversation, but the decision is made on the spot.

My battery says 26,800 mAh. Why does the exact voltage matter?

Because the limit falls inside the usual range: 99.16 Wh at 3.7 V is under it, and 103.18 Wh at 3.85 V is over it. For markings between roughly 26,000 and 27,700 mAh, the printed voltage is the only firm answer.

Sources and how they were checked#

The rules were re-read on 7 November 2026 on the Ryanair and UK authority pages. The Wizz Air page refused automated access that day, so the Wizz Air lines follow the official text indexed by search and deserve a look on the airline page before boarding. The positions above follow the values published then; airport and airline staff decide on the spot. Review recommended whenever the airline pages change and by May 2027 at the latest.