Battery Life Calculator

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power bank wh limit airplane

Power bank on a plane: how many mAh fit in 100 Wh

Type the power bank mAh and the cell voltage, usually 3.7 V, and the mAh, Wh and Ah tab shows the result in Wh with a range notice. Many device labels already state the Wh, and in that case use the printed number.

What the TSA says about lithium batteries

Airlines and authorities measure lithium batteries in watt-hours, not mAh, and the 100 Wh cut shows up in the rules. According to the TSA page on lithium batteries over 100 Wh, spares, power banks among them, go in the carry-on bag only. From 101 to 160 Wh, with airline approval, the TSA allows up to two per person. The page says nothing about batteries of 100 Wh or less or about those above 160 Wh.
The conversion uses the nominal cell voltage. At 3.7 V, the 100 Wh limit corresponds to 100 x 1,000 / 3.7 = 27,027 mAh, and the 160 Wh one to 43,243 mAh. So a 20,000 mAh power bank (74 Wh) and a 27,000 mAh one (99.9 Wh) sit within the limit, and a 30,000 mAh one (111 Wh) already needs approval. The math uses the nominal voltage, and the value printed on the label takes priority over the conversion.
Each airline's rules can be stricter than the TSA's, and authorities in other countries have their own rules, including on use on board. This page is a math aid, not an official ruling: confirm the limits and conditions with the airline and with the aviation authority of your route before you travel.

Power banks and the Wh range

10000 mAh at 3.7 V

Input: 10000 mAh, 3,7 V
Expected output: 37 Wh

Within 100 Wh.

27000 mAh at 3.7 V

Input: 27000 mAh, 3,7 V
Expected output: 99,9 Wh

Just below 100 Wh.

30000 mAh at 3.7 V

Input: 30000 mAh, 3,7 V
Expected output: 111 Wh

The 101 to 160 Wh range: needs airline approval.

43200 mAh at 3.7 V

Input: 43200 mAh, 3,7 V
Expected output: 159,84 Wh

Close to the 160 Wh ceiling.

45000 mAh at 3.7 V

Input: 45000 mAh, 3,7 V
Expected output: 166,5 Wh

Above 160 Wh, outside the range the TSA page covers.

Full tool FAQ

How do I convert mAh to Wh?

Multiply the mAh by the voltage in volts and divide by 1,000. A 20,000 mAh power bank at 3.7 V holds 20,000 x 3.7 / 1,000 = 74 Wh. To go back, Wh x 1,000 / V.

How long does a 12 V, 100 Ah battery last?

What are efficiency and depth of discharge here?

Why does a power bank deliver fewer mAh than advertised?

How do I estimate the runtime of a UPS?

What is the Wh limit for carrying batteries on a plane?

How do I calculate a series and parallel cell pack?

Does the calculator consider temperature, ageing and the Peukert effect?

How do I size a battery for a load and a runtime?

Does my data leave the browser?

Frequently asked questions

Can I put the power bank in checked luggage?

According to the TSA, spare lithium batteries, power banks included, go in the carry-on bag only. The 101 to 160 Wh range cannot be checked either. Confirm the conditions with your airline.

How many power banks can I bring?

For the 101 to 160 Wh range, the TSA speaks of up to two spare batteries per person, with approval. For up to 100 Wh the page consulted sets no number, and each airline may set its own. Ask before boarding with several.

Is the mAh to Wh conversion exact?

It uses the nominal voltage, which is an average. If the maker states the Wh on the label, that value counts for more. Use the conversion to estimate when only the mAh are visible.

Next steps

What the TSA says about lithium batteries

Airlines and authorities measure lithium batteries in watt-hours, not mAh, and the 100 Wh cut shows up in the rules. According to the TSA page on lithium batteries over 100 Wh, spares, power banks among them, go in the carry-on bag only. From 101 to 160 Wh, with airline approval, the TSA allows up to two per person. The page says nothing about batteries of 100 Wh or less or about those above 160 Wh.

The conversion uses the nominal cell voltage. At 3.7 V, the 100 Wh limit corresponds to 100 x 1,000 / 3.7 = 27,027 mAh, and the 160 Wh one to 43,243 mAh. So a 20,000 mAh power bank (74 Wh) and a 27,000 mAh one (99.9 Wh) sit within the limit, and a 30,000 mAh one (111 Wh) already needs approval. The math uses the nominal voltage, and the value printed on the label takes priority over the conversion.

Each airline's rules can be stricter than the TSA's, and authorities in other countries have their own rules, including on use on board. This page is a math aid, not an official ruling: confirm the limits and conditions with the airline and with the aviation authority of your route before you travel.

Power banks and the Wh range

10000 mAh at 3.7 V

Input: 10000 mAh, 3,7 V
Expected output: 37 Wh

Within 100 Wh.

27000 mAh at 3.7 V

Input: 27000 mAh, 3,7 V
Expected output: 99,9 Wh

Just below 100 Wh.

30000 mAh at 3.7 V

Input: 30000 mAh, 3,7 V
Expected output: 111 Wh

The 101 to 160 Wh range: needs airline approval.

43200 mAh at 3.7 V

Input: 43200 mAh, 3,7 V
Expected output: 159,84 Wh

Close to the 160 Wh ceiling.

45000 mAh at 3.7 V

Input: 45000 mAh, 3,7 V
Expected output: 166,5 Wh

Above 160 Wh, outside the range the TSA page covers.

Full tool FAQ

How do I convert mAh to Wh?

Multiply the mAh by the voltage in volts and divide by 1,000. A 20,000 mAh power bank at 3.7 V holds 20,000 x 3.7 / 1,000 = 74 Wh. To go back, Wh x 1,000 / V.

How long does a 12 V, 100 Ah battery last?

What are efficiency and depth of discharge here?

Why does a power bank deliver fewer mAh than advertised?

How do I estimate the runtime of a UPS?

What is the Wh limit for carrying batteries on a plane?

How do I calculate a series and parallel cell pack?

Does the calculator consider temperature, ageing and the Peukert effect?

How do I size a battery for a load and a runtime?

Does my data leave the browser?

Frequently asked questions

Can I put the power bank in checked luggage?

According to the TSA, spare lithium batteries, power banks included, go in the carry-on bag only. The 101 to 160 Wh range cannot be checked either. Confirm the conditions with your airline.

How many power banks can I bring?

Is the mAh to Wh conversion exact?

It uses the nominal voltage, which is an average. If the maker states the Wh on the label, that value counts for more. Use the conversion to estimate when only the mAh are visible.