How many watts does a slow cooker 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

A typical 3.5-litre slow cooker is rated at 160W to 200W, and uses at most 0.2 kWh an hour, about 2p to 5p an hour at 26.32p per kWh. An eight-hour stew comes to roughly 0.6 to 1.6 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: 160W to 200W
Amps at 230V (most): 0.87A
Energy an hour: 0.08 to 0.2 kWh; High: 200W for an hour, an upper bound as the element cycles. Low: Which? says the best slow cookers cost about 2p an hour on low (it gives no unit rate); at the current cap that would be about 0.08 kWh.
Cost an hour: 2p to 5p
On a 1kWh power station: 3.5 to 8.5 hours
On a 2kWh power station: 7.5 to 17 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

Russell Hobbs rates its 3.5-litre Chalkboard 24180 at 200W and Morphy Richards its Easy Time 3.5-litre at 0.16kW. The element cycles to hold temperature, so real use is below the rating: Which? found costs of 2p to 7p an hour on the lowest setting and 3p to 39p on the highest across the models it tested.

The honest bit

A slow cooker draws little but runs for hours, so its advantage over an oven is real but not dramatic for a short cook. For a long casserole it is one of the cheapest ways to cook, and it is one of the few cooking appliances a 1kWh power station can run for a full cook.

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

A 1kWh power station: 3.5 to 8.5 hours. A 2kWh power station: 7.5 to 17 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 200W before you rely on it.

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

Common questions

Is a slow cooker cheaper than an oven?

For a long cook, yes. A slow cooker draws about 200W at most; a built-in electric oven is rated near 3,000W, and Which? measured one using 1.157 kWh for a 76-minute roast. Which? puts an eight-hour stew at about 16p in an efficient slow cooker and about 40p in the least efficient.