Find the cheapest power bank, by the watt-hour.

A 20,000 mAh power bank at 3.7 V cell voltage actually holds 74 Wh of energy. A "20,000 mAh" laptop bank at 3.85 V holds about 77 Wh. Marketing copy uses the higher mAh of the internal cells, but you deliver fewer mAh at the 5 V USB output. Watt-hours collapse the confusion into one comparable number.

The TSA and most international airlines allow lithium-ion power banks under 100 Wh in carry-on baggage with no special permission. Between 100 and 160 Wh you need airline approval. Anything above 160 Wh is forbidden on passenger flights — so the Jackery Explorer 300 and Anker 535 power stations can't fly.

Once a day, via the Amazon Product Advertising API. We display the last refreshed price; the checkout price may differ — always click through to confirm before buying.

If you click a Buy link and complete a purchase, we earn a small affiliate commission at no cost to you. Rankings are deterministic from the $/Wh formula and cannot be paid for. We have no incentive to recommend a particular model over another.

We track popular models with verifiable specs. If a power bank you love is missing, email us the manufacturer spec sheet URL and we'll add it.