MundoKit

Power bank Wh calculator

Enter the rated mAh and matching nominal battery voltage. Calculate watt-hours and screen your identical power banks against dated flight capacity and quantity rules.

Inputs
mAh
V
Illustrative 3.7 V cell rating. Use the voltage on your battery label, not the USB output voltage.

Results

Energy per power bank
74 Wh
Capacity screening (2026)
Within 100 Wh carry-on threshold
Quantity screening (IATA 2026)
Within two-power-bank limit
Checked baggage
Power banks must stay in the cabin
  • Compare the manufacturer’s printed Wh rating first. This calculation is an estimate, not airline approval. Classification uses unrounded energy.
  • Protect each unit against short circuits. Remove power banks if your carry-on is checked at the gate. Do not carry damaged or recalled batteries.
  • IATA’s March 2026 guidance prohibits recharging a power bank on board and recommends against using one to recharge a device. Airlines may prohibit both. Confirm your route and airline rules.
  • IATA states the 100–160 Wh approval provision for power banks will not continue in its 2027 rules. Check again for travel in 2027.

Results update as you type. The share link stores your inputs after the # in the address, which is not sent to our server, but anyone you send it to can read them.

How it works

Wh = mAh × nominal voltage ÷ 1000

Anker documents this conversion and gives 20,000 mAh at 3.7 V as 74 Wh. Use the voltage corresponding to the rated mAh, commonly a nominal cell value such as 3.6 or 3.7 V. Do not combine a cell-rated mAh number with the 5 V USB output: the converter changes voltage and delivered mAh. Prefer the manufacturer’s printed Wh rating.

FAA PackSafe and IATA list up to 100 Wh as the usual carry-on threshold; above 100 through 160 Wh requires airline approval, with no more than two larger spares. Above 160 Wh is prohibited for ordinary passenger power banks. Power banks must never go in checked baggage, including bags checked at the gate. Protect terminals from short circuits.

IATA’s March 2026 operator guidance adds a maximum of two power banks per person regardless of capacity, prohibits recharging power banks in flight and recommends against using them to charge devices. It says the 100–160 Wh approval allowance for power banks will not continue in the 2027 DGR. Rules vary by jurisdiction and airline: this is a dated screening result, not permission to board.

Classification uses the unrounded calculated Wh, including fractional values above 100. Display rounds to at most four decimal places; there is no intermediate rounding.

Worked examples

20,000 mAh at 3.7 V

20,000 × 3.7 ÷ 1000 = 74 Wh per unit, within the 100 Wh capacity threshold. One unit is within the two-power-bank quantity limit.

30,000 mAh at 3.7 V

30,000 × 3.7 ÷ 1000 = 111 Wh per unit. In the 2026 guidance this needs airline approval; no more than two power banks may be carried.

50,000 mAh at 3.7 V

50,000 × 3.7 ÷ 1000 = 185 Wh, above the 160 Wh passenger capacity ceiling.

Frequently asked questions

Is a 20,000 mAh power bank allowed on a plane?
At 3.7 V it calculates to 74 Wh, below 100 Wh. Confirm the printed Wh rating, your airline’s rules and quantity limit; capacity alone does not guarantee acceptance.
Is exactly 100 Wh within the threshold?
Yes. Exactly 100 Wh is within the standard capacity threshold. Above 100 Wh through exactly 160 Wh needs airline approval under the cited 2026 guidance.
Can I pack it in checked baggage?
No. Power banks and spare lithium batteries must remain in the cabin. Remove them if your carry-on is checked at the gate.
Can I use a power bank during the flight?
Check the airline. Singapore Airlines prohibited both use and charging from April 1, 2025, and EVA Air from March 1, 2025. IATA’s March 2026 guidance prohibits recharging power banks and recommends against powering devices from them.
Can I bring three small power banks?
IATA’s March 2026 guidance limits personal power banks to two per person, even when each is under 100 Wh. Confirm local and airline implementation before travel.

Sources

Last reviewed 2026-11-14; next review due by 2026-12-31. The method is written out above so you can check our math.