USB-C Charger Power Budget Calculator

MEASURED INPUTS

Build the simultaneous power budget

Use documented device demand or the original adapter rating. Do not add device battery capacity here.

Primary device demandUse the largest device's documented USB-C input or original adapter rating.Simultaneous secondary loadAdd devices that must charge at the same time, not an overnight total.HeadroomA small margin covers conversion loss and avoids operating at the label ceiling.USB-C port countCount USB-C outputs you expect to use at once.

What the budget can and cannot establish

USB-C Power Delivery devices negotiate power instead of accepting a charger's full label. The calculation establishes a total target; it cannot prove that one port keeps the required allocation when another port is active. Verify the exact port table, device input, and cable rating before buying.

Read the charger compatibility manual USB-IF Power Delivery overview