How much electricity does a kettle use per month, and what does it cost?
A 3 kilowatt kettle uses about 0.15 kilowatt hours for a normal three minute boil, which costs 3.9p at the current Ofgem cap rate of 26.11p per kWh. Six boils a day comes to 27.3 kilowatt hours a month and £7.13, or £85.54 across a year.
What a kettle actually uses
A kettle is the simplest appliance in the house to work out. Almost every UK model is rated at 3 kilowatts, which is the practical ceiling for a thirteen amp plug, and Citizens Advice uses exactly that figure in its own worked example of appliance running costs. Cheaper and travel models sit around 2200 watts and take longer to do the same job.
Nearly all of that energy ends up in the water. The body of the kettle takes a little and the steam takes a little more, which is why boiling more water than you need is the only real waste available here.
The number that actually varies is how much you put in. Lifting one litre from fifteen degrees to boiling takes 0.099 kilowatt hours. Half a litre takes 0.049 and a full 1.7 litre kettle takes 0.168, so the same kettle can cost anything from a penny to four and a half pence depending on where you stop filling it.
The sum, worked in full
A three minute boil on a 3 kilowatt kettle is 3 multiplied by 0.05 hours, which is 0.15 kilowatt hours. At the cap rate of 26.11 pence that is 3.9p.
Six boils a day is 0.9 kilowatt hours, or 23.5p. Across a month that is 27.3 kilowatt hours and £7.13, and across a year it is £85.54. A household that boils twelve times a day, which is normal in a house of four tea drinkers, spends just over £171 a year on hot water for drinks.
Work it out for your own electric kettle
Type in the wattage from the plate on the back, then your own unit rate. The numbers update as you type.
What each fill costs
| What you boil | Energy used | Cost at 26.11p | Time at 3 kW |
|---|---|---|---|
| One mug, 250 ml | 0.025 kWh | 0.6p | 30 seconds |
| Minimum fill, 500 ml | 0.049 kWh | 1.3p | 1 minute |
| One litre | 0.099 kWh | 2.6p | 2 minutes |
| A full 1.7 litre kettle | 0.168 kWh | 4.4p | 3 minutes 24 seconds |
| A full hour of boiling | 3.00 kWh | 78.3p | 60 minutes |
| Appliance | Typical draw | Usage we assume | Per hour (UK) | Per usage (UK) | Per month (UK) | Per hour (US) |
|---|---|---|---|---|---|---|
| Electric kettle | 3000 W | per 3 minute boil | 78.3p | 3.9p | £7.13 | 55.0 cents |
Rates: Ofgem cap 1 July to 30 September 2026 at 26.11p per kWh (source), EIA residential average June 2026 at 18.34 cents per kWh (source). Checked 2026-09-22.
A word on the three minute boil used through this guide. It is the time a 3 kilowatt element needs for about a litre and a half of water, which is what most people put in without thinking. A kettle filled to the top takes three minutes and twenty four seconds and one filled to the minimum line takes a minute, so the boil time on your own kettle is a decent guide to how much water you have just paid to heat.
Readers in the United States can take the same six boils a day and multiply 27.3 kilowatt hours by the EIA residential average of 18.34 cents, which gives $5.01 a month. Most American kettles run on a 120 volt supply at around 1500 watts, so they take twice as long to boil the same water while using a similar amount of energy overall.
Five ways to cut the kettle bill
- Fill to the number of cups you are making. Boiling a full kettle for one mug costs 4.4p instead of 1.3p, and repeated six times a day that is £68 a year of hot water poured away.
- Do not reboil. Water that has already boiled and cooled costs exactly as much to heat again as fresh water did the first time.
- Descale it if you are in a hard water area. Scale on the element slows the boil and wastes the heat into the limescale rather than the water.
- Use a flask for the second cup. Pouring the spare into a flask keeps it hot for hours and costs nothing.
- Match the appliance to the job. A single mug of soup belongs in the microwave at about 0.8p, and a pan of water for pasta belongs on the hob.
Kettle against the hob and the microwave
The gas hob question comes up constantly. Gas is cheaper per unit at 7.33 pence against 26.11 pence for electricity, but an open flame around the base of a pan loses a lot of heat to the kitchen. If roughly half the gas heat reaches the water, boiling a litre on the hob costs about 1.4p against 2.6p in the electric kettle. The saving is real and it is about a penny, and the hob takes several times longer.
The microwave is the opposite case. It puts energy straight into the water, so a single mug heated for two minutes at 900 watts costs about 0.8p against 1.3p for the smallest boil most kettles allow. It wins on one mug and loses on everything larger, because a microwave heats slowly once there is real volume in the jug.
An eco kettle with a measured pour does the same thing as careful filling and costs forty pounds to buy, so the payback depends entirely on whether you would have filled it properly anyway. The same goes for a hot water tap, which holds a small tank at temperature all day in exchange for saving you the boil.
So the kettle stays. It is fast, it is nearly all useful heat, and the only meaningful saving is the one in your own hand, which is the line you fill it to.
Common questions
How much does it cost to boil a kettle for one cup?
A single mug of 250 millilitres needs 0.025 kilowatt hours of heat, which is 0.6p. Most kettles will not boil less than half a litre though, and that costs 1.3p, so the cheapest real world cup is about a penny.
How much does it cost to run a kettle for 1 hour?
78.3p, since a 3 kilowatt kettle uses 3 kilowatt hours in an hour. No kettle runs for an hour, but the figure is useful as a reminder that the kettle is one of the biggest loads in the kitchen while it is switched on.
How much does it cost to run a kettle per year?
£85.54 for a household boiling six times a day, using 3.9p a boil at the current cap rate. Twelve boils a day doubles it to just over £171.
Is it cheaper to use a kettle or a microwave?
The microwave is cheaper for one mug, at about 0.8p for two minutes at 900 watts against 1.3p for the smallest boil a kettle will do. For anything more than a mug the kettle wins, because it heats water far faster and loses less of the heat to the air.