Kettle Boil Time & Cost Calculator
With energy prices making up a real chunk of household bills, knowing what each boil actually costs helps you spot easy savings — like only filling the kettle to the level you need. Enter your kettle's details below to see the boil time and cost.
Work out your kettle's boil time and cost
Enter your kettle's wattage, the water you're boiling, and your electricity price.
Boiling that water will take approximately:
1 min 59 sec
That costs around 2.7p per boil — roughly 37 boils for every £1 of electricity.
Recommended products
A few well-reviewed kettles.
- Black
- 1.7L Kettle / 4 Slice Toaster
£62.99
Pros
- Matching cordless kettle and 4-slice toaster in one set
- Rapid boil 3kW kettle element
- Independent extra-wide slots with 6 browning levels
Cons
- Honeycomb texture shows fingerprints more than a plain finish
- Emerald Green
- 1.7L
£169.30
Pros
- Iconic 50s retro styling in a standout colour
- Superfast 3000W boil with balanced pour spout
- Removable limescale filter and auto shut-off
Cons
- Premium price for a kettle
- Large body takes up more worktop space than a slim jug kettle
- White
- 2 Slice
£94.99
Pros
- Toasts up to 60 slices an hour
- Wide 36mm slots handle thick and artisan bread
- Bagel and defrost settings included
Cons
- No digital display, dial timer only
Frequently asked questions
Does boiling only the water I need actually save money?
Yes — boiling a full kettle when you only need one mug wastes a surprising amount of energy, since you are heating water you will simply pour away. Filling to the level you actually need is one of the easiest ways to cut the cost of each boil.
Why do two kettles with the same wattage take different times to boil?
Boil time depends on how much water you put in and the starting temperature, not just the wattage. A kettle filled from a warm tap or with less water will reach boiling point faster than one filled to the brim with cold water.
Is a higher wattage kettle always cheaper to run?
Not necessarily — a higher wattage kettle boils water faster, but it draws more power while it runs, so the total energy (and cost) used per litre boiled is broadly similar. The main benefit of a higher wattage kettle is convenience, not a lower bill.
How much does electricity price affect the cost per boil?
Quite a lot over time — a change of a few pence per kWh might only shift a single boil by a fraction of a penny, but multiplied across dozens of boils a week it adds up, so it is worth checking your current unit rate rather than an old one.
How this calculator works
The calculator uses your kettle's wattage (found on a label on the base or in the product specifications) and the volume of water it’s heating. It then applies a simplified model based on the energy required to raise the temperature of that water, calculating the time needed for the kettle to reach boiling point (100°C). The calculator assumes continuous heating – meaning the kettle remains on until boiling is achieved.
We've used an average electricity price of £0.27 per kWh in the UK as of October 2024. This figure represents the cost of one kilowatt-hour of electricity. The calculation factors this rate into the energy cost estimate to provide a realistic reflection of your expenditure. Note that actual prices can vary slightly depending on your supplier and tariff.
Kettle Wattage & Water Volume Considerations
- Smaller kettles (e.g., 0.7 litre) typically have lower wattage (1200-1800W) and will boil faster, resulting in a lower cost per boil.
- Larger kettles (e.g., 1.5 litre or more) generally use higher wattage (2000W+) to heat the larger volume of water effectively and have a longer boiling time, increasing the overall cost.
- The type of heating element – glass-coated plates versus stainless steel – can slightly influence heating speed, though this is usually minor when compared to kettle size and wattage.
- Always check your kettle's manual or product details for precise wattage information; variations exist between manufacturers.
Worked example: Boiling a 1.5 Litre Kettle
Let’s say you have a kettle with a 1800W heating element and you’re boiling 1.5 litres (1500ml) of water. The calculator estimates the time to boil as approximately 6 minutes 30 seconds. This is based on the energy required to raise the temperature from room temperature (around 18°C) to 100°C, accounting for heat loss and assuming continuous heating.
Using our £0.27/kWh electricity rate, the cost of a single boil would be approximately £0.35. Over a year with an average of 6 boiled litres per day (approximately 1284 boils), you’d spend around £304 on boiling water – a significant amount! Investing in a more energy-efficient kettle could save you considerable money over time.
More questions answered
What if my electricity price is different?
The calculator uses an average UK electricity price of £0.27/kWh, but this will vary depending on your energy supplier and tariff. To get a more accurate cost estimate, simply replace the default price with your actual kWh rate in pence.
Does the calculator account for heat loss?
Yes, the calculation incorporates an estimated factor for heat loss from the kettle to the surrounding environment. However, this is a simplification; factors like room temperature and insulation levels aren't considered.
How accurate are the boiling times?
The calculated boiling times are estimates based on typical kettle performance. Actual boiling times can vary slightly depending on water quality, initial water temperature, and the specific kettle model.
What if I only boil a small amount of water?
Even when boiling a small quantity, the calculator will still calculate the energy used to heat that volume. The cost per boil remains relatively consistent regardless of the volume, making it useful for comparing different kettles.
Can I use this calculator for electric jugs?
Yes, you can! Just enter the wattage of your electric jug into the calculator and the water volume. However, electric jugs often have lower wattages than standard kettles, so the boiling time will generally be shorter.
What happens if I switch between different kettle sizes?
Simply input the new water volume and wattage for each boil to get an accurate cost estimate. The calculator automatically adjusts the calculation based on these inputs.
Does this calculator include any taxes or VAT?
No, the calculations are based purely on the electricity price and do not factor in any applicable taxes or Value Added Tax (VAT).
What if my kettle has a variable wattage setting?
Use the highest wattage setting available for your kettle when using this calculator to ensure the most accurate cost estimate. It’s better to overestimate than underestimate.
Is this calculator suitable for calculating the running costs of a hot water system?
No, this calculator is designed specifically for estimating the cost of boiling individual quantities of water in a standard kettle. It does not account for the energy used by larger hot water systems or immersion heaters.
How can I ensure my kettle wattage figure is correct?
Wattage is typically printed on a label located on the base of your kettle, often near the power cord connection. If you cannot find this information, consult your kettle's user manual or contact the manufacturer for specifications.