To check just by entering the numbers, use the checker.
Power banks are categorized by their watt-hour rating (Wh).
| Wh | Rule |
|---|---|
| 100Wh or less | Allowed in carry-on (not in checked baggage) |
| Over 100Wh up to 160Wh | Allowed in carry-on (not in checked baggage). Limited in number together with spare batteries for cameras etc. (see 5 below) |
| Over 160Wh | Not allowed in carry-on or checked baggage |
Power banks are limited to 2 per person regardless of capacity (160Wh or less only) (from April 24, 2026).
Sources (2)
Source: MLIT: "To All Passengers: Regarding Bringing Power Banks on Board" (English version) (retrieved 2026-09-27)
Source: Japan Ministry of Land, Infrastructure, Transport and Tourism (MLIT): new rules for carrying power banks on board (announced April 14, 2026; applied from April 24, 2026) [in Japanese] (retrieved 2026-09-27)
Example from the table below (rated voltage 3.7V)
Some power banks show the "rated capacity (mAh)" and "rated voltage (V)" instead of Wh. MLIT's documents use the following formula.
- Wh = rated capacity (mAh) × rated voltage (V) ÷ 1,000
- MLIT's example: rated capacity 27,000mAh, rated voltage 3.7V → 27,000 × 3.7 ÷ 1,000 = 99.9Wh (100Wh or less)
- If the product shows Wh, use that number as it is.
🔋 Calculate yours
Enter mAh and V, or Wh.
Source
Source: MLIT: "To All Passengers: Regarding Bringing Power Banks on Board" (English version) (retrieved 2026-09-27)
PR Example power bank (Japanese online stores)
rated battery capacity 3.7V/10000mAh 37.0Wh, labeled as meeting PSE technical standards.
capacity 10000mAh; the label on the unit reads 5000mAh 7.2Vdc / 36Wh; PSE (notifying company: アンカー・ジャパン株式会社).
The table below is calculated assuming a rated voltage of 3.7V. Rated voltage differs by product, so calculate with the label on your own product.
| Rated capacity | Wh at 3.7V | Category |
|---|---|---|
| 5,000mAh | 18.5Wh | 100Wh or less |
| 10,000mAh | 37Wh | 100Wh or less |
| 20,000mAh | 74Wh | 100Wh or less |
| 27,000mAh | 99.9Wh | 100Wh or less |
| 30,000mAh | 111Wh | over 100Wh up to 160Wh |
| 40,000mAh | 148Wh | over 100Wh up to 160Wh |
| 45,000mAh | 166.5Wh | over 160Wh (not allowed) |
At a rated voltage of 3.7V, the 100Wh limit is crossed between 27,000mAh (99.9Wh) and 30,000mAh (111Wh). With a different rated voltage, the mAh at the limit also changes, so if your product is close to the limit, calculate with the label on your own product.
PR Example power bank (Japanese online stores)
capacity 20000mAh / 74.0Wh, labeled as meeting PSE technical standards.
capacity 20000mAh; a photo of the label on the unit shows 3.85V (77Wh); PSE (notifying company: 株式会社CIO).
The formula uses the value labeled "rated voltage" on the product (3.7V in MLIT's example). Using the USB output (OUTPUT) such as "5V" makes the Wh come out larger than it really is.
For example, 26,800mAh calculated at 5V is 134Wh, which falls into the over-100Wh category. At a rated voltage of 3.7V, it is about 99Wh, which is 100Wh or less.
If you cannot find the rated voltage or Wh, do not guess; ask your airline.
Power banks are limited to 2 per person regardless of capacity. Those over 100Wh up to 160Wh are limited to 2 in total together with spare lithium-ion batteries for cameras etc. (over 100Wh up to 160Wh).
| Power banks you take | Spare batteries (over 100Wh up to 160Wh) |
|---|---|
| 100Wh or less × 2 | Up to 2 |
| 100Wh or less × 1 + over 100Wh up to 160Wh × 1 | Up to 1 |
| Over 100Wh up to 160Wh × 2 | Not allowed |
Spare lithium metal batteries (over 2g up to 8g) for portable medical electronic devices (AED, CPAP, etc.) also count toward these 2. Spare batteries of 100Wh or less have no quantity limit (carry-on only). Power banks with sodium-ion batteries are not allowed in carry-on or checked baggage.
Sources (2)
Source: MLIT: "To All Passengers: Regarding Bringing Power Banks on Board" (English version) (retrieved 2026-09-27)
Source: MLIT: "Examples of Dangerous Goods by Air Transportation" (English version, last updated April 24, 2026) (retrieved 2026-09-27)
- Do not put them in checked baggage; carry them on board
- Prevent short circuits: apply insulating tape to the terminals, place them in a case or storage bag, etc.
- Do not place them in overhead compartments. Keep them close to you, e.g. in the seat pocket
- Do not charge power banks on board, and do not charge phones or other devices from a power bank on board (from April 24, 2026)
Some airlines have stricter rules. See also New power bank rules.
Sources (2)
Source: MLIT: "To All Passengers: Regarding Bringing Power Banks on Board" (English version) (retrieved 2026-09-27)
Source: Japan Ministry of Land, Infrastructure, Transport and Tourism (MLIT): new rules for carrying power banks on board (announced April 14, 2026; applied from April 24, 2026) [in Japanese] (retrieved 2026-09-27)
Handy to have before you go
PR Example plug adapter (Japanese online stores)
Match the socket shape at your destination (voltage is not converted)
supports plugs A, B, BF, B3, C, SE, O, O2 and CB (the store's names), rated 6A 250V. It cannot convert voltage and cannot be used in Japan, the page says.
supports types A, O, BF, C and SE (the store's names), 100-240V. It does not convert voltage and cannot be used in Japan, the page says.