How many watts does a laptop use?

By Tom Calder · Figures checked 4 November 2026 · Costs at 26.32p per kWh (Ofgem cap, 1 October to 31 December 2026)

In short

Most laptops draw 30W to 70W from the mains, the adapter’s rating being the most they draw while working and charging at once. An hour costs at most 0.8p to 2p at 26.32p per kWh.

A kettle coming to the boil beside a microwave and slow cooker in a warmly lit kitchen on a rainy evening

The numbers

Running watts: 30W to 70W
Amps at 230V (most): 0.3A
Energy an hour: 0.03 to 0.07 kWh; Adapter ratings for an hour, an upper bound for most use.
Cost an hour: 0.8p to 2p
On a 1kWh power station: 9.5 to 19 hours
On a 2kWh power station: 19 to 38 hours

Costs use 26.32p per kWh, the Ofgem price cap's average Direct Debit electricity unit rate for 1 October to 31 December 2026. Your own rate is on your bill; on a fixed or time-of-use tariff it will differ.

How it’s used, and what that costs

Apple lists 30W and 35W adapters for the MacBook Air, 67W to 96W for the 14-inch MacBook Pro and 140W for the 16-inch. A big 16-inch or gaming laptop can exceed 70W, and a laptop running on its own battery while only being topped up draws far less.

The honest bit

In a power cut, charging it from a power station’s USB-C port, or a large power bank, avoids the losses of the mains socket.

In a power cut: how long a power station would run it

A 1kWh power station: 9.5 to 19 hours. A 2kWh power station: 19 to 38 hours. These use the same planning method as our power station pages: capacity × 90% usable depth × 85% inverter efficiency, divided by the load plus about 10W the unit uses itself (BLUETTI’s UK formula).

Output matters as much as capacity. The 7 units around 1kWh we list supply 1,500W to 2,000W continuously, and the 6 around 2kWh supply 2,200W to 3,000W, so check a unit’s rated output covers 70W before you rely on it.

To size one for everything you’d want to keep running, use the sizer on our power stations comparison.