mAh vs Wh: Key Battery Capacity Difference Explained
mAh (milliampere-hours) counts total charge—how many tiny electrons a battery can hold. Wh (watt-hours) counts total energy—how much actual work those electrons can do, combining charge and voltage.
We see 5 000 mAh on power banks and assume “bigger is better,” yet a 5 000 mAh phone may die faster than a 3 000 mAh tablet. That confusion sparks the mix-up: same number, different power demands.
Key Differences
mAh = capacity at a single voltage; Wh = capacity across any voltage. Double the voltage and the same mAh delivers twice the Wh. Airlines care about Wh, not mAh, for safety limits.
Which One Should You Choose?
Use mAh when comparing phones with identical 3.7 V batteries. Use Wh when judging laptops, drones, or TSA rules—because 100 Wh is the carry-on ceiling, regardless of mAh.
Examples and Daily Life
Your 10 000 mAh power bank is 37 Wh—safe for flights. A 70 Wh laptop pack at 7 200 mAh might seem smaller but packs far more punch, running a high-res screen longer.
Can I fly with a 30 000 mAh power bank?
If it stays under 100 Wh (roughly 27 000 mAh at 3.7 V), yes. Check the label.
Why does my 4 000 mAh phone die by noon?
High screen brightness and 5G drain energy faster than the mAh figure alone suggests.