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No. A slow cooker draws about 70 to 150 watts on low and 150 to 250 watts on high, which is roughly a tenth of what a toaster oven or kettle pulls. Eight hours on low uses close to one kilowatt-hour, or about 16 cents at the recent US residential average of roughly 17 cents per kWh reported by the Energy Information Administration. Even used twice a week year-round, the appliance adds under 20 dollars to an annual bill. It is one of the cheapest ways to cook a braise, and considerably cheaper than running a full oven for the same hours.
How many watts does a slow cooker actually draw?
Less than most people guess, because the appliance is designed around low, sustained heat rather than fast heating. Resistance elements wrapped around the outer housing hold the crock at roughly 190 to 200 degrees Fahrenheit on low and 200 to 300 on high, and holding a temperature takes far less power than reaching one.
| Size | Low setting | High setting | 8 hours on low |
|---|---|---|---|
| 2 qt | ~70–90 W | ~120–150 W | ~0.6 kWh / ~10¢ |
| 4 qt | ~90–120 W | ~150–200 W | ~0.8 kWh / ~14¢ |
| 6 qt | ~120–150 W | ~200–250 W | ~1.0 kWh / ~17¢ |
| 8 qt | ~150–200 W | ~250–300 W | ~1.4 kWh / ~24¢ |
Costs above use 17 cents per kilowatt-hour. Substitute the rate printed on your own utility bill — US residential prices span roughly 12 to 30 cents depending on the state, which changes the figures by more than the appliance size does.

How does it compare with using the oven?
It is not close. A full electric oven holding 325 degrees Fahrenheit for a four-hour braise consumes somewhere in the region of 6 to 8 kilowatt-hours after preheat and thermostat cycling, because it is maintaining a 5-cubic-foot insulated cavity at a much higher temperature. A slow cooker doing the same job over eight hours uses about one. That is roughly a dollar a meal in favor of the slow cooker, before you count the air conditioning load of a hot kitchen in summer.
The comparison reverses for short cooking. Nothing about a slow cooker helps with a 20-minute roast of vegetables, and for that a toaster oven at 1,500 watts for 20 minutes uses about 0.35 kWh — cheaper than an hour of anything else. Cost per kilowatt-hour varies widely by state; the national average is published in the US Energy Information Administration's published average retail price of electricity to residential customers. Match the appliance to the job and the energy question mostly answers itself.

Low or high — which is cheaper?
They land in roughly the same place, and it is not worth optimizing. High draws about twice the wattage of low but finishes in about half the time, so total energy for the same dish comes out broadly similar, often marginally in favor of high because the pot spends less total time losing heat to the room.
The choice matters for texture, not cost. Long, low cooking is what breaks collagen down into gelatin in chuck, shoulder and shank, which is the entire point of the appliance. Choose low when you want the meat to fall apart and you are out of the house, and high when you started late.

Is it safe and economical to leave it running all day?
Yes on both counts, and the appliance was designed for exactly that. Slow cookers are certified to run unattended for extended periods, they operate at low wattage with no exposed flame, and the cost of a 10-hour cook is around 20 cents. On the food-safety side the USDA says food stays safe for as long as the cooker is operating, and that meat and poultry should always be thawed before they go in. The safety practices worth keeping are the ordinary ones: place it on a heat-resistant surface away from the wall and from anything flammable, do not run it under a low cabinet where steam collects, use a wall outlet rather than an extension cord, and inspect the cord for damage. The USDA advises that a slow cooker should bring food out of the 40 to 140 degree Fahrenheit danger zone promptly, which means starting with thawed rather than frozen ingredients and keeping the crock between half and two-thirds full.
Where to go next
If the all-day question is what brought you here, leaving a slow cooker on all day and leaving one on overnight cover it directly. For results, see what temperature a slow cooker reaches on low and whether you can overcook meat. Weighing appliances? Slow cooker versus Instant Pot compares them, and the best slow cookers ranks models on aggregated owner ratings, inside the small kitchen appliances hub.
We never buy or physically handle the products we rank — our picks come from aggregated owner reviews and expert consensus, explained on how we rank.
