A typical electric kettle uses around 2,000–3,000 watts (2–3kW) while heating water. Boiling one litre of water generally uses approximately 0.10–0.12 kilowatt-hours (kWh) of electricity, while boiling enough for a single cup uses considerably less.

At an illustrative electricity price of 25p per kWh, boiling one litre costs around 2.5–3p. The actual cost depends on the amount of water, its starting temperature, the kettle’s efficiency and your electricity tariff.

How much electricity does a kettle use per boil?

The amount of electricity a kettle consumes depends mainly on how much water you’re heating.

Most UK electric kettles have a capacity of around 1.5–1.7 litres. However, filling the kettle completely requires more electricity than boiling enough water for one or two cups.

The following table shows approximate consumption for different amounts of water.

Amount of water	Approximate electricity use
One mug (250ml)	0.03 kWh
Two mugs (500ml)	0.05–0.06 kWh
One litre	0.10–0.12 kWh
1.5 litres	0.15–0.18 kWh
Full 1.7-litre kettle	0.17–0.20 kWh

These are illustrative estimates for heating cold tap water to boiling, allowing for some heat loss. Actual consumption varies between kettles and conditions.

As you can see, boiling more water generally uses more electricity.

Always respect the kettle’s minimum and maximum fill levels, even when preparing a single drink.

How much does it cost to boil a kettle?

Boiling a kettle usually costs only a few pence, but the price varies depending on the amount of water and your electricity tariff.

For the examples below, we’ll use an illustrative electricity unit rate of 25p per kWh.

Amount of water	Electricity used	Approximate cost
One mug (250ml)	0.03 kWh	0.75p
Two mugs (500ml)	0.055 kWh	1.4p
One litre	0.11 kWh	2.75p
1.5 litres	0.165 kWh	4.1p
Full 1.7-litre kettle	0.19 kWh	4.75p

The 25p/kWh rate is an example, not the current national electricity price. The estimates exclude standing charges.

For a more accurate result, check the electricity unit rate shown on your bill.

Standing charges are separate because you generally pay them regardless of whether you use the kettle.

How much does it cost to boil a full kettle?

At the illustrative rate of 25p/kWh, a full 1.7-litre kettle costs around 4–5p per boil.

That’s roughly twice the cost of heating one litre and several times the cost of boiling a single mug.

If you regularly fill the kettle but only use half the water, reducing the amount could make a noticeable difference over time.

How much does boiling a kettle cost per day and year?

The cost of using your kettle depends on how often you boil it and how much water you heat each time.

For example, suppose you boil one litre of water each time, using approximately 0.11kWh.

At our illustrative rate of 25p/kWh, the costs would be:

One-litre boils per day	Daily cost	Annual cost
2	5.5p	£20.08
4	11p	£40.15
6	16.5p	£60.23
8	22p	£80.30

These examples assume the same number of boils every day throughout the year. They’re not measured UK household averages.

Your actual costs may be lower if you’re regularly boiling water for just one mug, or higher if you frequently fill the kettle completely.

The annual cost can also change if your electricity tariff changes.

Does a 3,000W kettle use more electricity than a 2,000W kettle?

Not necessarily.

A 3,000W kettle draws more electrical power while it’s operating than a 2,000W kettle, but it generally heats the same amount of water faster.

For example:

Kettle power	Illustrative boiling time	Electricity consumed
2,000W	3 minutes	0.10 kWh
3,000W	2 minutes	0.10 kWh

Both kettles consume the same amount of electricity in this example.

This is because wattage describes the rate at which a kettle uses electricity, not the total electricity required for a boil.

A higher-wattage kettle doesn’t automatically cost more to operate if it finishes heating the water sooner.

Actual differences depend on the kettle’s design, efficiency and how quickly it switches off when the water reaches boiling point.

Does boiling less water save electricity?

Yes. One of the easiest ways to reduce kettle electricity consumption is to avoid heating water you don’t need.

If you’re making one cup of tea, there’s usually no reason to boil enough water for four cups.

Heating extra water requires additional energy, even if you leave most of it in the kettle afterwards.

Avoiding unnecessary kettle overfilling could save around £10 per year in Great Britain and £12 in Northern Ireland, based on its published assumptions.

The exact saving depends on how much water you currently waste, how often you use the kettle, and your electricity price.

A kettle with a clear water-level indicator can make it easier to measure the right amount.

Some models also have one-cup markings or features designed to heat only the required quantity.

Does descaling a kettle reduce electricity use?

Limescale can accumulate inside kettles, particularly in areas with hard water.

These deposits may affect heating performance and can make the appliance harder to maintain.

Regular descaling helps keep the kettle clean and operating as intended.

However, descaling doesn’t guarantee a particular reduction in electricity consumption. The effect depends on how much scale is present and the kettle’s design.

Follow the manufacturer’s instructions and use a descaling product suitable for the appliance.

Keeping the kettle clean is sensible maintenance, but avoiding unnecessary water heating is generally a more straightforward way to reduce consumption.

Is it cheaper to boil a kettle or use the hob?

For heating relatively small amounts of water, an electric kettle is usually an efficient option.

Its heating element transfers energy directly to the water, while a hob may also heat the pan and surrounding air.

However, the cheapest method depends on the type of hob, the amount of water and the prices you pay for electricity and gas.

For example, a gas hob may use cheaper fuel per unit of energy but lose more heat to its surroundings.

An induction hob can transfer heat to a suitable pan more efficiently than a conventional gas hob.

Consequently, there’s no single answer that applies to every household.

For making tea or coffee, a kettle is usually the most convenient option. If you’re already cooking and need boiling water for a recipe, your preferred method may depend on the circumstances.

Is it cheaper to reboil a kettle?

Reboiling water that’s still warm generally requires less electricity than heating the same amount from cold.

However, repeatedly boiling more water than you need still wastes energy.

For example, boiling a full kettle for one cup, letting the remaining water cool and then reheating it later can consume more electricity than heating only the required amount each time.

If you frequently make hot drinks throughout the day, consider how much water you actually use rather than automatically refilling the kettle to maximum.

The most effective habit is usually to boil the necessary amount when you need it.

How can you measure your kettle’s electricity consumption?

The figures in this article are estimates. If you want to know exactly how much electricity your own kettle uses, you can measure it with an energy monitor (Energy Monitor vs Smart Meter: What’s the Difference?).

A suitable plug-in electricity monitor fits between the wall socket and the kettle’s plug.

It records the electricity used during a complete boiling cycle, typically in kilowatt-hours.

For a useful measurement, you could test the kettle with 500ml, one litre and its maximum capacity, provided these quantities comply with the manufacturer’s fill markings.

The results will help you understand how consumption changes with the amount of water.

You can also enter your electricity unit rate into some monitors to estimate the cost of each boil.

A smart meter’s in-home display may show the increase in overall household electricity consumption while the kettle operates, but it doesn’t isolate kettle consumption from other appliances.

How can you reduce kettle running costs?

You don’t necessarily need a new kettle to reduce electricity use.

The most useful habits are straightforward:

• Boil only the water you need. Avoid filling the kettle unnecessarily.
• Use the water-level markings. These can help you estimate the right quantity.
• Respect the minimum fill level. Never operate the kettle below the manufacturer’s specified minimum.
• Avoid unnecessary reboiling. If the water is already hot enough for your purpose, reheating it may not be necessary.
• Descale when needed. Follow the manufacturer’s cleaning instructions to maintain the appliance.

If you’re replacing an old kettle, consider models with clear measuring marks, automatic shut-off and suitable minimum-fill requirements.

However, buying a new kettle purely to save electricity may not be financially worthwhile if your existing appliance works efficiently and reliably.

Frequently asked questions

How much electricity does a kettle use in five minutes?

A 3,000W kettle operating continuously for five minutes would consume approximately 0.25kWh, costing around 6.25p at an illustrative rate of 25p/kWh. Most kettles switch off automatically once the water boils, so actual consumption depends on the operating time.

How much does it cost to boil a kettle for one cup of tea?

Heating approximately 250ml of water might use around 0.03kWh, costing about 0.75p at 25p/kWh. The kettle must support that quantity within its minimum-fill requirements.

How much electricity does a 3kW kettle use?

A 3kW kettle draws up to approximately 3,000W while heating. Its total electricity consumption depends on how long it operates. For example, a two-minute boil at full power uses approximately 0.10kWh.

Does a kettle use electricity when switched off?

A basic kettle with a mechanical switch generally uses no electricity when switched off. Some models with electronic displays, temperature controls or keep-warm functions may consume a small amount while plugged in.

Are energy-efficient kettles worth buying?

They can be useful, particularly when features such as one-cup boiling or accurate water measurement help prevent overfilling. However, the savings depend on your habits, and replacing a working kettle solely for energy efficiency may not recover the purchase cost.

Sources

Ofgem, Energy Price Cap Unit Rates and Standing Charges (https://www.ofgem.gov.uk/your-energy-supply/your-energy-bill/energy-price-cap-unit-rates-and-standing-charges)

Accurate as of: 31 October 2026