Quick answer
With the default example, 20,000 mAh at 3.7 V is 74 Wh. This power bank is at or below 100 Wh, which is usually allowed in carry-on baggage. Power banks should be kept in carry-on baggage, not checked baggage.
How to use this power bank flight limit calculator
First check the power bank label. If it lists watt-hours (Wh), enter that value directly. If it only lists milliamp-hours (mAh), enter the battery voltage from the label. Many power banks list mAh at 3.7 V or 3.85 V, not at the 5 V USB output.
The result compares the calculated Wh against the common flight ranges: at or below 100 Wh, above 100 Wh up to 160 Wh, and above 160 Wh. The middle range usually requires airline approval.
If your question is how long a power bank or backup battery can run network equipment, use the Router Backup Power Runtime Calculator. If your question is charging time, use the Battery Charging Time Calculator.
Power bank mAh to Wh formula
Wh = mAh x voltage / 1000mAh = Wh x 1000 / voltage100 Wh at 3.7 V = about 27,027 mAh160 Wh at 3.7 V = about 43,243 mAhFlight rules use watt-hours because Wh measures stored energy. mAh alone is incomplete unless the battery voltage is known. For power banks, use the rated battery voltage from the label when converting mAh to Wh.
Assumptions and methodology
This calculator is built for consumer lithium-ion power banks and portable chargers. It uses the common passenger-baggage ranges used by many aviation authorities and airlines: up to 100 Wh, 101-160 Wh with approval, and over 160 Wh as over the usual passenger limit.
- Power banks are treated as spare lithium batteries and should be carried in cabin baggage.
- The calculator does not override airline, airport, or country rules, which can be stricter.
- Damaged, recalled, swollen, leaking, unlabeled, or modified batteries can be refused even if the Wh value is within range.
- For labels that show both mAh and Wh, use Wh as the more direct value for flight-limit checks.
Example calculations
20,000 mAh power bank flight example
A common 20,000 mAh power bank rated at 3.7 V is calculated as 20,000 x 3.7 / 1000 = 74 Wh.
That is below the common 100 Wh no-approval threshold, so it is usually allowed in carry-on baggage. It should not be placed in checked baggage, and the airline can still apply its own quantity or safety rules.
A 30,000 mAh power bank at 3.7 V is about 111 Wh. That moves into the approval-required range for many airlines, even though it is still below 160 Wh.
Power bank flight limit chart
These examples assume the mAh rating is based on the battery cell voltage shown. If your product label gives Wh, use that value directly.
| Power bank | Calculated Wh | Carry-on | Checked baggage | Approval | Result |
|---|---|---|---|---|---|
| 10,000 mAh power bank | 37 Wh | Carry-on only | No checked bag | Usually no | Usually allowed in carry-on |
| 20,000 mAh power bank | 74 Wh | Carry-on only | No checked bag | Usually no | Usually allowed in carry-on |
| 27,000 mAh power bank | 99.9 Wh | Carry-on only | No checked bag | Usually no | Usually allowed in carry-on |
| 30,000 mAh power bank | 111 Wh | Carry-on only | No checked bag | Required | Airline approval required |
| 50,000 mAh power bank | 185 Wh | Carry-on only | No checked bag | Required | Not allowed for normal passenger baggage |
| 160 Wh battery pack | 160 Wh | Carry-on only | No checked bag | Required | Airline approval required |
What to check on the power bank label
Look for Wh first. If the label only shows mAh, look for the battery voltage near the capacity rating. Do not assume the large mAh number is rated at 5 V USB output. Many lithium-ion power banks advertise mAh at internal cell voltage, commonly around 3.7 V.
Keep the printed rating visible when traveling. A power bank with no readable rating, visible damage, swelling, recalled model status, or exposed terminals can create problems even if the calculated Wh seems acceptable.
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FAQ
Can I bring a 20,000 mAh power bank on a plane?
Usually yes if the power bank is around 3.7 V internally. A 20,000 mAh power bank at 3.7 V is about 74 Wh, which is below the common 100 Wh no-approval limit. It should still be carried in cabin baggage, not checked baggage.
Is a 30,000 mAh power bank allowed on a flight?
It depends on the battery voltage. At 3.7 V, 30,000 mAh is about 111 Wh, which is above 100 Wh but below 160 Wh. That range typically requires airline approval and is usually limited in quantity.
Can I put a power bank in checked baggage?
No for normal spare power banks. Power banks are treated as spare lithium batteries and should be carried in the cabin, with terminals protected from short circuit.
Why do airlines use Wh instead of mAh?
Watt-hours measure stored energy. mAh depends on voltage, so the same mAh number can mean different energy depending on the battery pack voltage.
What power bank size is usually under 100 Wh?
At 3.7 V, 100 Wh is about 27,000 mAh. Many 10,000 mAh and 20,000 mAh power banks are under 100 Wh, but always check the actual Wh rating printed on the product label.
Are 100-160 Wh power banks completely banned?
Not always. They are commonly allowed only with airline approval and typically in limited quantities. The calculator marks this range as approval required, not automatically allowed.
What if the power bank label does not show Wh?
Use the mAh and voltage printed on the label to estimate Wh. If the label is unclear, damaged, or missing, airport staff or the airline may reject it, even if the calculated value seems acceptable.
Can airline rules be stricter than this calculator?
Yes. Airlines, airports, and countries can apply stricter rules, especially for quantity, damaged batteries, recalled products, or unlabeled batteries. Confirm the airline policy before travel.