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Air travel · Battery

Power Bank Wh Calculator

Choose a common capacity or enter the value printed on your power bank. If Wh is already printed on the label, use that value first.

Capacity
Nominal battery voltage

Use the nominal battery voltage printed with the cell capacity (often 3.7V or 3.85V), not the USB output voltage such as 5V/9V/12V.

Result 74 Wh

Generally within the ≤100Wh carry-on range

Power banks must stay in carry-on baggage. Airline, route and country rules can be stricter.

Formula: (20,000 ÷ 1,000) × 3.7 = 74Wh

✈️ 2026 IATA/ICAO guidance limits passengers to no more than two power banks per person and prohibits recharging a power bank onboard. Airline rules may be stricter.
Rules checked: 2026-09-21 · This calculator is a convenience tool, not a boarding or carriage guarantee. Rules can change and actual acceptance is determined by the airline, airport, route and applicable authority. Check the latest official source before travel.

How the calculation works

Watt-hours measure battery energy. When a label shows mAh and nominal voltage, Wh = (mAh ÷ 1,000) × V. For example, 20,000mAh at 3.7V is 74Wh.

Quick examples

10,000mAh · 3.7V37Wh
20,000mAh · 3.7V74Wh
27,000mAh · 3.7V99.9Wh
30,000mAh · 3.7V111Wh

Before you fly

Can I put a power bank in checked baggage?

No. Spare lithium batteries and power banks must be carried in hand baggage under IATA guidance.

Is 100Wh always allowed?

No. It is a common upper range for normal carry-on treatment, but airlines, airports and countries may impose stricter limits.

My power bank says 20,000mAh but no Wh. What do I do?

Use the nominal cell voltage printed on the product label. If the voltage or capacity cannot be verified, an airline may refuse carriage.

Official sources

Rules checked: 2026-09-21