How the laptop power bank calculator works
The wattage gate
USB-C Power Delivery negotiates: the laptop requests its profile (45/65/100 W) and the bank must OFFER it. A 30 W bank next to a 65 W laptop is a paperweight with good intentions — no negotiation, no charging, regardless of capacity. The gate is output wattage; the spec line reads "PD output: 65 W."
The Wh arithmetic
Laptop batteries run 40–100 Wh; a 100 Wh bank (85% usable) adds 85 Wh — roughly one full recharge of an ultrabook or 1.5–2 hours of a power-hungry workstation. The runtime line in the calculator is the honest travel promise: "the bank buys two more hours of real work."
The airline layer
Banks are carry-on only, capped at 100 Wh without approval (100–160 Wh with airline approval, maximum two). A 100 Wh bank is the practical laptop-travel ceiling — right at the limit, no approval needed, and genuinely useful. Print or screenshot the Wh rating; security occasionally asks.