The short answer (checked 8 November 2026)
- Best overall is the Russell Hobbs 20441, the number one kettle on Amazon UK this week. Its own manual allows a single 235ml cup, so the smallest boil it permits costs at least 0.65p at the October 2026 price cap.
- Best for tea drinkers is the Ninja Perfect Temperature KT200UK. Heating a 250ml mug to 80C instead of 100C cuts the energy by 22 per cent, from 0.69p to 0.53p.
- Wattage buys speed, not savings. A 3kW kettle and a 2.2kW kettle put the same energy into the same water; the 3kW one just finishes sooner.
- What decides the cost of a cup is how little water the kettle lets you boil. A one-mug kettle used five times a day costs at least £12.55 a year to run. A kettle that forces a 500ml minimum doubles that to £25.10.
- Audit finding: of the top twenty kettles on Amazon UK's Electric Kettles chart, read on 8 November 2026, none states a minimum fill in its title, bullet points or specification tables. Eight claim a one-cup boil time, and only two of those eight say how big the cup is.
Every kettle on this page boils water, and every 3kW kettle uses the same amount of electricity to boil the same amount of water. Physics does not allow one 3kW kettle to be much cheaper than another per litre. So we ranked by the one thing that does change the bill: the smallest amount of water each maker's own instructions let you boil. That figure sets the cost of the cup of tea you make most often. It also turns out to be the figure the listings leave out.
How this page was made
Prices and specs last checked by Look Into on 8 November 2026 · next check 1 January 2027 · how we picked
Prices in this table come from Amazon and are refreshed at least once a day, with the date of the last update under the table. The cost-per-use and running-cost figures on this page use prices Look Into read on 8 November 2026, so they can differ from today's price.
What a boil actually costs
Heating water takes 4.18 kilojoules per kilogram for every degree, the textbook figure for water. We assume cold tap water at 10C, which is about right for a UK winter, and a boil at 100C, so a rise of 90 degrees. One litre therefore needs 4.18 x 90 = 376.2 kJ, which is 0.1045 kWh. At the Ofgem price cap of 26.32p per kWh (1 October to 31 December 2026, GB average, Direct Debit, standing charge excluded), that is 2.75p a litre.
| Water boiled | Energy into the water | Cost per boil (floor) | Five a day for a year |
|---|---|---|---|
| 235ml (one Russell Hobbs cup) | 0.0246 kWh | 0.65p | £11.80 |
| 250ml (one mug) | 0.0261 kWh | 0.69p | £12.55 |
| 500ml (a common minimum fill) | 0.0523 kWh | 1.38p | £25.10 |
| 1.7 litres (a full kettle) | 0.1777 kWh | 4.68p | £85.33 |
These are floors. They count only the heat that ends up in the water. Some heat goes into the kettle body, the element and the air, so your meter will read more. One maker's own claim gives a sense of how much: Cosori says its kettle boils 250ml in 43 seconds at 3,000W. That is 3 x 43 / 3,600 = 0.0358 kWh drawn for water that needs at least 0.0261 kWh, or about 37 per cent above the floor if the water started at 10C. Cosori does not say what temperature the water started at, so treat that as an illustration rather than a measurement.
The same arithmetic sets a speed limit. A 3kW kettle cannot bring 250ml from 10C to the boil in less than 31 seconds, because that is how long 3kW takes to deliver 0.0261 kWh. Every one-cup time claimed in the chart sits above that line, between 43 and 54 seconds, so none of them is impossible. None of them can be checked from the listing either, for the reasons below.
How we picked these
We read the top twenty of Amazon UK's Electric Kettles Best Sellers chart on the morning of 8 November 2026, then opened each of the twenty listings and read the title, the bullet points and the specification tables. For the shortlist we then opened the instruction manual each maker supplies on its Amazon listing, because that is where a minimum fill is written down when it is written down at all. We picked six kettles that do different jobs, each with a minimum fill or wattage we could tie to a maker's own document. We did not fill, time or measure any of them.
As an Amazon Associate, Look Into earns from qualifying purchases. Product prices and availability are accurate as of 8 November 2026 6:45 pm and are subject to change.Compare live prices for every pick
How they compare
| Kettle | Smallest boil the maker allows | Where that figure comes from | Cost of that boil (floor) | Power |
|---|---|---|---|---|
| Russell Hobbs 20441 | 1 cup, 235ml | Instruction manual on the Amazon listing | 0.65p | 3kW |
| Breville Bold VKT22x | About 250ml | Instruction manual on the Amazon listing | 0.69p | 3kW |
| Ninja Perfect Temperature KT200UK | 250ml | John Lewis listing for the KT201UK version | 0.69p at 100C, 0.53p at 80C | 3kW |
| Russell Hobbs Honeycomb 26051 | 1 cup, volume not stated | Instruction manual on the Amazon listing | Not calculable | 3kW |
| Russell Hobbs 23840 travel kettle | 1 cup, volume not stated | Russell Hobbs instruction leaflet | Not calculable | 1kW |
| Daewoo Essentials SDA1567 | A MIN mark with no volume | Instruction manual on the Amazon listing | Not calculable | 1.85 to 2.2kW |
Russell Hobbs 20441 Brushed Stainless Steel, 1.7L
Price: check the live price on Amazon · 3kW · minimum 1 cup (235ml) · number 1 in Electric Kettles, 8 November 2026
This is the kettle more people are buying than any other this week, and it is the one whose paperwork is clearest. The manual on its Amazon listing says to fill with at least one cup, and its diagram labels that cup as 235ml. That makes it the lowest legitimate boil on this page: 0.65p at the cap, or £11.80 a year for five single mugs a day. It has internal 1, 2 and 3 cup marks, a removable anti-scale filter and a push-to-open lid.
The catch: the 235ml figure is in the manual, not on the listing. The listing itself never tells you the minimum, so you would only know if you downloaded the PDF. Brushed steel also shows water marks and fingerprints more than plastic does.
Breville Bold Electric Kettle, 1.7L
Price: check the live price on Amazon · 3kW · minimum about 250ml · number 9 in Electric Kettles, 8 November 2026
Breville's manual for the Bold range (models VKT221, VKT222, VKT223 and VKT226) says the kettle needs approximately 250ml, or one teacup, to work correctly. That puts its smallest boil at 0.69p, a whisker behind the Russell Hobbs. It comes in several colours, which is most of the reason people buy it, and the listing gives the 3kW rating plainly.
The catch: "approximately" is the manual's word, and the kettle has no 250ml mark that the listing mentions, so you are judging one cup by eye. The listing says nothing about a minimum at all.
Ninja Perfect Temperature Kettle KT200UK, 1.7L
Price: check the live price on Amazon · 3kW · minimum 250ml · number 5 in Electric Kettles, 8 November 2026
This is the only kettle here that can stop short of boiling. It has presets from 60C to 100C and holds a temperature for up to 30 minutes. Green and white teas are usually brewed well below boiling, and stopping at 80C instead of 100C means a 70 degree rise rather than 90, which is 22 per cent less energy. For a 250ml mug that is 0.53p instead of 0.69p, or £9.76 a year instead of £12.55 at five mugs a day. The 250ml minimum fill is stated on John Lewis's listing for the stainless KT201UK version of the same kettle.
The catch: it costs several times what the others do, and the saving from lower temperatures is a few pounds a year, so it will never pay for itself on electricity. Buy it for the tea, not the bill. The keep-warm hold also draws power while it runs, which eats into any saving if you leave it on.
Russell Hobbs Honeycomb 26051, 1.7L
Price: check the live price on Amazon · 3kW · minimum 1 cup (volume not stated) · number 2 in Electric Kettles, 8 November 2026
The second best seller has internal 1, 2 and 3 cup indicators and a manual that says to fill with at least one cup, so it is built for single mugs in the same way as the 20441. Its textured plastic body hides marks better than steel.
The catch: the listing promises "Boil One Cup in 43 Seconds*", and the asterisk leads nowhere. We found no footnote in the title or the bullet points, and the instruction manual on the listing does not mention the claim or say how big the cup is. So we cannot cost its smallest boil, and you cannot check the 43 seconds.
Russell Hobbs 23840 Travel Kettle, 0.85L
Price: check the live price on Amazon · 1kW · minimum 1 cup (volume not stated) · number 11 in Electric Kettles, 8 November 2026
A 1kW kettle for caravans, hotel rooms, student rooms and anywhere the circuit will not take 3kW. It comes with two cups and two spoons that pack inside it, and the instructions say to fill with at least one cup. Low wattage does not make a cup cheaper: the water still needs the same 0.0261 kWh. It just takes longer, at least 94 seconds for 250ml and over five minutes for a full 0.85 litres.
The catch: it is slow and small, and Russell Hobbs's own troubleshooting guide says it holds less water than a standard kettle and takes longer to boil. As a main kitchen kettle it will frustrate a household.
Daewoo Essentials 1.7L Fast Boil Kettle (SDA1567)
Price: check the live price on Amazon · 1.85 to 2.2kW · MIN mark, volume not stated · number 4 in Electric Kettles, 8 November 2026
The cheapest kettle in the top twenty, and a plain white plastic jug that does the job. Its manual rates it at 1,850 to 2,200W. Despite "Fast Boil" in the title, that makes it the slowest full-size kettle here: a full 1.7 litres takes at least four minutes 51 seconds at 2.2kW, against three minutes 33 seconds at 3kW. The energy, and so the cost, is the same.
The catch: the manual tells you to keep the water above the MIN mark without saying how much water that is. If the mark sits at 500ml, every single mug costs you a second mug's worth of electricity. Check the mark in the kettle before you rely on it for one cup.
What the twenty listings actually say
We read the title, bullet points and specification tables of all twenty kettles in the Amazon UK Electric Kettles top twenty on 8 November 2026. Here is what we found.
- None of the twenty states a minimum fill. This is the number that decides what your most common cup of tea costs, and it is not on any of the twenty listings. Where it exists, it is in the PDF manual.
- Eight of the twenty claim a one-cup boil time, ranging from 43 to 54 seconds.
- Only two of those eight say how big the cup is. Cosori gives 250ml. The Russell Hobbs Groove gives two different cups in the same listing: one bullet point says a single 236ml cup and the next says one 235ml cup.
- Three of the eight timing claims come with no wattage anywhere in the title, bullets or specification tables (a Russell Hobbs brushed steel model claiming 45 seconds, the Groove claiming 54 seconds, and the Tower Cavaletto claiming under 45 seconds). A time with no cup size and no wattage cannot be checked.
- Only one timing claim gives a starting temperature, and only loosely: the Groove says "from tap", which in the UK can mean anything from about 5C in winter to 20C in summer.
None of this means the kettles are bad. The 3kW models all boil about as fast as a UK socket allows. It means the listings sell speed, which barely differs between them, and leave out the minimum fill, which does differ and is the part that costs you money.
Who should not bother upgrading
If your current kettle has a one-cup mark and you already fill it to that mark, a new kettle will not lower your bill. Every 3kW kettle uses the same energy per litre, and there is no energy label for kettles to suggest otherwise. The saving comes from the habit: filling to one mug instead of half a kettle saves about 0.7p a boil at the cap. Replace a kettle when it is scaled up, leaking or failing to switch off, not to save electricity.
For more on what your kitchen appliances cost to run, see the UK Running Cost Index, the cheapest way to cook compared and our coffee cost per cup index. If limescale is your problem rather than the kettle, our guide to water filter jugs works through what a filtered litre costs.
Questions people ask
Does a 3kW kettle use more electricity than a 2.2kW one?
No. Both put the same energy into the same amount of water. The 3kW kettle draws more power for a shorter time, so a litre costs about 2.75p either way at the October 2026 cap, before heat losses. The difference is speed.
How much does it cost to boil a kettle in the UK?
At 26.32p per kWh, heating water from 10C to boiling costs at least 0.69p for a 250ml mug and at least 4.68p for a full 1.7 litre kettle. Real costs are somewhat higher because some heat goes into the kettle and the air.
What is the minimum fill on a kettle?
It is the least water the maker says the kettle needs to work safely and switch itself off. On the kettles we checked it ranged from one cup (235ml in Russell Hobbs's own diagram) to an unlabelled MIN mark. It is usually in the instruction manual and, on the twenty best sellers we read, never on the Amazon listing.
Does a temperature-control kettle save money?
A little. Stopping at 80C instead of 100C cuts the energy for that boil by 22 per cent, which is about 0.15p on a 250ml mug. At five mugs a day that is under £3 a year, so it will not repay the higher price of the kettle. It is worth buying for the taste of the drink, not the saving.
Are the "one cup in 43 seconds" claims true?
They are physically possible. A 3kW kettle needs at least 31 seconds to bring 250ml from 10C to the boil, and every claim we found is slower than that. But most of the claims do not say how big the cup is or how cold the water started, and three do not give a wattage, so you cannot check them from the listing.
Sources
- Ofgem, Energy price cap unit rates and standing charges, 1 October to 31 December 2026, checked 8 November 2026.
- Amazon UK, Electric Kettles Best Sellers, top twenty, and each of the twenty product listings, read 8 November 2026.
- Russell Hobbs instruction manual supplied on the Amazon listing for the 20441 (1 cup minimum, cup labelled 235ml), read 8 November 2026.
- Russell Hobbs instruction manual supplied on the Amazon listing for the 26051 Honeycomb (1 cup minimum, no volume), read 8 November 2026.
- Breville Bold Collection instruction manual, VKT221/222/223/226, supplied on the Amazon listing (approximately 250ml), read 8 November 2026.
- Daewoo Essentials SDA1567 user manual supplied on the Amazon listing (MIN mark, 1,850 to 2,200W), read 8 November 2026.
- Russell Hobbs 23840 instruction leaflet (at least 1 cup) and troubleshooting guide (1000W), read 8 November 2026.
- John Lewis, Ninja KT201UK Perfect Temperature Kettle (250ml minimum fill, presets 60C to 100C), checked 8 November 2026.
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