The job: carrying watt-hours that will pass a bag check.
A power bank is sold in milliamp-hours and regulated in watt-hours, and that mismatch is the single most useful thing to understand before buying one. The conversion this site uses everywhere is watt-hours equals milliamp-hours divided by 1000, times 3.7.
Run the arithmetic and the picture clears up fast. A 10000 mAh bank is roughly 37 Wh. A 25000 mAh bank is roughly 92.5 Wh, which is under the commonly published 100 Wh threshold but close enough to be worth checking with the airline before a trip rather than at the gate.
The second thing to know is that the nameplate is stored capacity, not delivered capacity. Converting the cell voltage up to what a phone accepts costs energy, and so does wireless transfer. Every bank hands over less than it holds.
Links to Amazon on this page are affiliate links, and a qualifying purchase may earn this site a commission at no extra cost to you. It changes nothing about what is written here: no prices, no ratings, and no claims of our own testing. Affiliate Disclosure.
How to choose one
What to weigh
What to look for
Why it matters
Watt-hours, not milliamp-hours
The capacity converted with mAh ÷ 1000 × 3.7
Carriers publish thresholds in watt-hours. Doing the conversion at home is the whole point of the flight check tool on this site.
Output wattage
A stated wattage or a stated voltage and current
A 5V 3A bank is 15W and a 45W bank states three times that. Both can hold the same energy; they differ in how quickly the listing says they will move it.
Recharge speed
Whether the input rate is stated separately from the output
A bank that takes all night to refill itself is a bank you will forget to refill.
Cable strategy
Detachable, built-in, or none
Built-in cables cannot be lost and cannot be replaced. Detachable cables are the opposite bargain.
Charge indicator
An LED percentage rather than four dots
Four dots is a rounding error you cannot plan around. A number is a number.
Magnetic
Attaches to the back of the phone. Convenient, less efficient than a cable, and it contains magnets.
2 listings in this subgroup.
18.5 Wh, smallest here
Anker 621 MagGo Power Bank, 5000 mAh
Magnetic
A flat 5000 mAh pack that the listing states attaches magnetically, with a USB-C cable included. Five thousand milliamp-hours is roughly 18.5 Wh, the smallest figure in this category and the least likely to raise a question anywhere. Magnetic attachment means it rides on the back of the phone instead of dangling from it.
Per port
Manufacturer does not publish the split
Capacity
5,000 mAh ≈ 18.5 Wh
Ports
USB-C stated
Cable
USB-C cable stated
The listing states: Magnetic attachment and a USB-C cable.
A slim 5000 mAh magnetic pack with 20W PD stated on the wired side. Around 18.5 Wh by the standard formula. Wireless transfer through a magnetic coupling is convenient and also the least efficient way to move energy, so the phone gets meaningfully less than the label suggests.
Stated total
20W
Per port
20W PD stated
Capacity
5,000 mAh ≈ 18.5 Wh
Ports
USB-C stated
The listing states: 20W PD, an ultra-slim magnetic wireless pack.
A top-up that rides on the phone rather than in a bag.
podoru Magnetic Power Bank, 5000 mAh
20W
20W PD stated
None stated
20W PD
A pocket top-up with no cable involved.
Anker 621 MagGo Power Bank, 5000 mAh
Stated total
Not stated
Per-port figure
Not published
Cable
USB-C cable stated
The listing leads with
Magnetic attachment
Best for
A top-up that rides on the phone rather than in a bag.
podoru Magnetic Power Bank, 5000 mAh
Stated total
20W
Per-port figure
20W PD stated
Cable
None stated
The listing leads with
20W PD
Best for
A pocket top-up with no cable involved.
Built-in cables
Cables live in the body and cannot be forgotten. They also cannot be replaced when they wear.
4 listings in this subgroup.
charmast Power Bank with 4 Cables, 10000 mAh
Built-in cables
Four cables built into the body, six outputs and three inputs by the listing, at 10000 mAh. That is roughly 37 Wh. The appeal is that it cannot be separated from its cables; the cost is that a worn built-in cable is a worn power bank.
Per port
Manufacturer does not publish the split
Capacity
10,000 mAh ≈ 37 Wh
Ports
6 outputs and 3 inputs stated
Cable
Four built-in cables stated
The listing states: Four built-in cables, six outputs, three inputs, and 3A.
A 10000 mAh bank with its own fold-out wall plug, built-in cables, and pass-through charging stated. Pass-through means it can charge the phone while it is itself charging from the wall, which turns it into a wall charger that keeps working when unplugged. Roughly 37 Wh by the standard formula.
Stated total
20W
Per port
PD 20W stated
Capacity
10,000 mAh ≈ 37 Wh
Ports
Built-in cables plus a wall plug stated
Cable
Built-in cables stated
The listing states: PD 20W, built-in cables and a wall plug, and pass-through charging.
Four built-in cables plus two open ports, with an LED percentage display. The display is worth more than it sounds: a bank that shows a real number instead of four dots is a bank you can plan around. Ten thousand milliamp-hours is roughly 37 Wh.
Per port
Manufacturer does not publish the split
Capacity
10,000 mAh ≈ 37 Wh
Ports
5 outputs stated
Cable
Four built-in cables stated
The listing states: Four built-in cables, two ports, an LED display, and five outputs.
Built-in cables, a wall plug, and an LED display on a 10000 mAh body, which is roughly 37 Wh. It is the same everything-in-one idea as the other plug-equipped bank here, with the display included. Five outputs is more than one bank this size can serve quickly.
Per port
Manufacturer does not publish the split
Capacity
10,000 mAh ≈ 37 Wh
Ports
5 outputs stated
Cable
Built-in cables and wall plug stated
The listing states: Built-in cables, a wall plug, five outputs and an LED display.
One object instead of a charger, a cable, and a bank.
VRURC Power Bank with 4 Cables, 10000 mAh
Not stated
Not published
5 outputs stated
Four built-in cables stated
Four built-in cables
Anyone who has been caught out by a four-dot battery indicator.
VEGER Power Bank with Cables and Plug, 10000 mAh
Not stated
Not published
5 outputs stated
Built-in cables and wall plug stated
Built-in cables
A travel bag where every extra object is one too many.
charmast Power Bank with 4 Cables, 10000 mAh
Stated total
Not stated
Per-port figure
Not published
Ports
6 outputs and 3 inputs stated
Cable
Four built-in cables stated
The listing leads with
Four built-in cables
Best for
A shared bank for a group with mismatched phones.
citicr Power Bank with Plug, 10000 mAh
Stated total
20W
Per-port figure
PD 20W stated
Ports
Built-in cables plus a wall plug stated
Cable
Built-in cables stated
The listing leads with
PD 20W
Best for
One object instead of a charger, a cable, and a bank.
VRURC Power Bank with 4 Cables, 10000 mAh
Stated total
Not stated
Per-port figure
Not published
Ports
5 outputs stated
Cable
Four built-in cables stated
The listing leads with
Four built-in cables
Best for
Anyone who has been caught out by a four-dot battery indicator.
VEGER Power Bank with Cables and Plug, 10000 mAh
Stated total
Not stated
Per-port figure
Not published
Ports
5 outputs stated
Cable
Built-in cables and wall plug stated
The listing leads with
Built-in cables
Best for
A travel bag where every extra object is one too many.
Standard
A rectangle with ports. The most efficient, the most repairable, and the least interesting to look at.
4 listings in this subgroup.
37 Wh by the formula
INIU 45W Power Bank, 10000 mAh
Standard
Ten thousand milliamp-hours with 45W stated, which is the size that still fits a pocket paired with a rate the listing actually publishes. Run it through the watt-hour formula and 10000 mAh lands near 37 Wh, far below the threshold most carriers publish. The detachable cable means the cable is replaceable rather than a failure point.
Stated total
45W
Per port
Manufacturer does not publish the split
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB-C stated
Cable
Detachable USB-C cable stated
45W is the total budget for the whole unit across every port at once, not what a single phone is handed.
The listing states: 45W charging and a detachable USB-C cable.
Twenty-five thousand milliamp-hours, which the standard formula puts at roughly 92.5 Wh: under the usual 100 Wh threshold, but close enough that it is worth doing the arithmetic before an airport rather than at one. The listing states 165W total with three USB-C ports at 100W maximum each, and those two numbers cannot all happen at once. That is what a total means.
Stated total
165W
Per port
100W maximum stated per USB-C port
Capacity
25,000 mAh ≈ 92.5 Wh
Ports
3 x USB-C stated
Cable
Retractable cables stated
165W is the total budget for the whole unit across every port at once, not what a single phone is handed.
The listing states: 165W total output, three USB-C ports at 100W max each, and retractable cables.
Ten thousand milliamp-hours with 30W stated on a USB-C port that works in both directions. Around 37 Wh by the standard formula. The bidirectional port is the useful detail: one cable refills the bank and the same cable empties it into a phone.
Stated total
30W
Per port
30W stated on the USB-C port
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB-C in and out stated
The listing states: 30W with USB-C input and output.
Ten thousand milliamp-hours at a stated 5V and 3A, which multiplies out to 15W. That is the slow, cool, undramatic end of charging, and it is fine for an overnight top-up or a device that does not negotiate anything clever. Roughly 37 Wh of stored energy.
Stated total
15W
Per port
5V at 3A stated, which is 15W
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB stated
The listing states: 5V 3A charging, ultra-compact.
A day away from an outlet, in a bag that goes through a scanner.
Anker Laptop Power Bank, 25000 mAh
165W
100W maximum stated per USB-C port
25,000 mAh ≈ 92.5 Wh
3 x USB-C stated
Retractable cables stated
165W total output
A long travel day with a laptop and a phone.
Anker 30W Power Bank, 10000 mAh
30W
30W stated on the USB-C port
10,000 mAh ≈ 37 Wh
USB-C in and out stated
None stated
30W with USB-C input
The uncomplicated bank that lives in a backpack.
Anker PowerIQ Power Bank, 10000 mAh
15W
5V at 3A stated, which is 15W
10,000 mAh ≈ 37 Wh
USB stated
None stated
5V 3A charging
Overnight top-ups where speed is not the point.
INIU 45W Power Bank, 10000 mAh
Stated total
45W
Per-port figure
Not published
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB-C stated
Cable
Detachable USB-C cable stated
The listing leads with
45W charging
Best for
A day away from an outlet, in a bag that goes through a scanner.
Anker Laptop Power Bank, 25000 mAh
Stated total
165W
Per-port figure
100W maximum stated per USB-C port
Capacity
25,000 mAh ≈ 92.5 Wh
Ports
3 x USB-C stated
Cable
Retractable cables stated
The listing leads with
165W total output
Best for
A long travel day with a laptop and a phone.
Anker 30W Power Bank, 10000 mAh
Stated total
30W
Per-port figure
30W stated on the USB-C port
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB-C in and out stated
Cable
None stated
The listing leads with
30W with USB-C input
Best for
The uncomplicated bank that lives in a backpack.
Anker PowerIQ Power Bank, 10000 mAh
Stated total
15W
Per-port figure
5V at 3A stated, which is 15W
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB stated
Cable
None stated
The listing leads with
5V 3A charging
Best for
Overnight top-ups where speed is not the point.
Everything in Power Banks, side by side
The whole category, on the stated figures only
Product
Subgroup
Stated total
Per-port figure
Capacity
Ports
Cable
The listing leads with
Best for
INIU 45W Power Bank, 10000 mAh
Standard
45W
Not published
10,000 mAh ≈ 37 Wh
USB-C stated
Detachable USB-C cable stated
45W charging
A day away from an outlet, in a bag that goes through a scanner.
Anker Laptop Power Bank, 25000 mAh
Standard
165W
100W maximum stated per USB-C port
25,000 mAh ≈ 92.5 Wh
3 x USB-C stated
Retractable cables stated
165W total output
A long travel day with a laptop and a phone.
Anker 621 MagGo Power Bank, 5000 mAh
Magnetic
Not stated
Not published
5,000 mAh ≈ 18.5 Wh
USB-C stated
USB-C cable stated
Magnetic attachment
A top-up that rides on the phone rather than in a bag.
Anker 30W Power Bank, 10000 mAh
Standard
30W
30W stated on the USB-C port
10,000 mAh ≈ 37 Wh
USB-C in and out stated
None stated
30W with USB-C input
The uncomplicated bank that lives in a backpack.
charmast Power Bank with 4 Cables, 10000 mAh
Built-in cables
Not stated
Not published
10,000 mAh ≈ 37 Wh
6 outputs and 3 inputs stated
Four built-in cables stated
Four built-in cables
A shared bank for a group with mismatched phones.
citicr Power Bank with Plug, 10000 mAh
Built-in cables
20W
PD 20W stated
10,000 mAh ≈ 37 Wh
Built-in cables plus a wall plug stated
Built-in cables stated
PD 20W
One object instead of a charger, a cable, and a bank.
VRURC Power Bank with 4 Cables, 10000 mAh
Built-in cables
Not stated
Not published
10,000 mAh ≈ 37 Wh
5 outputs stated
Four built-in cables stated
Four built-in cables
Anyone who has been caught out by a four-dot battery indicator.
VEGER Power Bank with Cables and Plug, 10000 mAh
Built-in cables
Not stated
Not published
10,000 mAh ≈ 37 Wh
5 outputs stated
Built-in cables and wall plug stated
Built-in cables
A travel bag where every extra object is one too many.
podoru Magnetic Power Bank, 5000 mAh
Magnetic
20W
20W PD stated
5,000 mAh ≈ 18.5 Wh
USB-C stated
None stated
20W PD
A pocket top-up with no cable involved.
Anker PowerIQ Power Bank, 10000 mAh
Standard
15W
5V at 3A stated, which is 15W
10,000 mAh ≈ 37 Wh
USB stated
None stated
5V 3A charging
Overnight top-ups where speed is not the point.
INIU 45W Power Bank, 10000 mAh
Subgroup
Standard
Stated total
45W
Per-port figure
Not published
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB-C stated
Cable
Detachable USB-C cable stated
The listing leads with
45W charging
Best for
A day away from an outlet, in a bag that goes through a scanner.
Anker Laptop Power Bank, 25000 mAh
Subgroup
Standard
Stated total
165W
Per-port figure
100W maximum stated per USB-C port
Capacity
25,000 mAh ≈ 92.5 Wh
Ports
3 x USB-C stated
Cable
Retractable cables stated
The listing leads with
165W total output
Best for
A long travel day with a laptop and a phone.
Anker 621 MagGo Power Bank, 5000 mAh
Subgroup
Magnetic
Stated total
Not stated
Per-port figure
Not published
Capacity
5,000 mAh ≈ 18.5 Wh
Ports
USB-C stated
Cable
USB-C cable stated
The listing leads with
Magnetic attachment
Best for
A top-up that rides on the phone rather than in a bag.
Anker 30W Power Bank, 10000 mAh
Subgroup
Standard
Stated total
30W
Per-port figure
30W stated on the USB-C port
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB-C in and out stated
Cable
None stated
The listing leads with
30W with USB-C input
Best for
The uncomplicated bank that lives in a backpack.
charmast Power Bank with 4 Cables, 10000 mAh
Subgroup
Built-in cables
Stated total
Not stated
Per-port figure
Not published
Capacity
10,000 mAh ≈ 37 Wh
Ports
6 outputs and 3 inputs stated
Cable
Four built-in cables stated
The listing leads with
Four built-in cables
Best for
A shared bank for a group with mismatched phones.
citicr Power Bank with Plug, 10000 mAh
Subgroup
Built-in cables
Stated total
20W
Per-port figure
PD 20W stated
Capacity
10,000 mAh ≈ 37 Wh
Ports
Built-in cables plus a wall plug stated
Cable
Built-in cables stated
The listing leads with
PD 20W
Best for
One object instead of a charger, a cable, and a bank.
VRURC Power Bank with 4 Cables, 10000 mAh
Subgroup
Built-in cables
Stated total
Not stated
Per-port figure
Not published
Capacity
10,000 mAh ≈ 37 Wh
Ports
5 outputs stated
Cable
Four built-in cables stated
The listing leads with
Four built-in cables
Best for
Anyone who has been caught out by a four-dot battery indicator.
VEGER Power Bank with Cables and Plug, 10000 mAh
Subgroup
Built-in cables
Stated total
Not stated
Per-port figure
Not published
Capacity
10,000 mAh ≈ 37 Wh
Ports
5 outputs stated
Cable
Built-in cables and wall plug stated
The listing leads with
Built-in cables
Best for
A travel bag where every extra object is one too many.
podoru Magnetic Power Bank, 5000 mAh
Subgroup
Magnetic
Stated total
20W
Per-port figure
20W PD stated
Capacity
5,000 mAh ≈ 18.5 Wh
Ports
USB-C stated
Cable
None stated
The listing leads with
20W PD
Best for
A pocket top-up with no cable involved.
Anker PowerIQ Power Bank, 10000 mAh
Subgroup
Standard
Stated total
15W
Per-port figure
5V at 3A stated, which is 15W
Capacity
10,000 mAh ≈ 37 Wh
Ports
USB stated
Cable
None stated
The listing leads with
5V 3A charging
Best for
Overnight top-ups where speed is not the point.
Questions that come up at the counter
How do I convert mAh to watt-hours?
Divide the milliamp-hour figure by 1000 and multiply by 3.7, the nominal cell voltage. A 10000 mAh bank is about 37 Wh; a 25000 mAh bank is about 92.5 Wh.
Can I put a power bank in checked baggage?
Lithium power banks belong in carry-on baggage and not in checked baggage. The rules are published by the FAA and by each airline, and the airline is the one that decides at the gate.
Why does a 10000 mAh bank not charge my 5000 mAh phone twice?
Because energy is lost converting the bank cell voltage up to what the phone accepts, and lost again as heat. The nameplate describes what is stored, not what is delivered.
Does "TSA approved" on a listing mean anything?
It is a seller claim. Neither the TSA nor the FAA approves individual power bank models. Do the watt-hour arithmetic and check your airline.
What should I do with a bank that is swollen, wet or hot?
Stop using it and stop charging it. Do not open it, do not puncture it, and follow local guidance for battery disposal.
Links to Amazon on this page are affiliate links, and a qualifying purchase may earn this site a commission at no extra cost to you. It changes nothing about what is written here: no prices, no ratings, and no claims of our own testing. Affiliate Disclosure.
