Free Tools

Quick calculators for the questions we get most about batteries, chargers, solar and drones. They’re free, run in your browser, and need no sign-up. Each one uses the same math as our explainers, so you can see exactly how we got the answer.

Batteries & Charging

Power Bank CalculatorConvert mAh to Wh, see how many real charges you will get, and check the 100Wh airline limit. USB-C Charger & Cable CalculatorPick your devices and get the charger wattage, port count and cable rating you actually need.

Solar & Backup Power

Power Station & Solar Generator CalculatorSize a portable power station for an outage or camp trip: inverter watts, battery Wh and solar panels. Plug-In Balcony Solar Savings CalculatorEstimate yearly kWh, bill savings and payback for an 800W plug-in solar kit.

FPV & Drones

Tiny Whoop Flight Time CalculatorEstimate minutes per pack for a 1S or 2S tiny whoop, and how many packs a session takes. LiPo Charging Time CalculatorHow long a bag of whoop packs takes to charge, the safe charge rate, and how many packs keep you flying nonstop. Drone Registration & 250g Rule CheckerCheck whether your drone needs FAA registration, Remote ID or a Part 107 license under the 250g rule.