Kettle vs. Induction Hob

The true cost of 'overfilling' your kettle.

Boiling Habits
e.g. 250ml for one big cup
Overfilling waste happens here!
Money Wasted
26,74

per year by overfilling

70.0% of energy is wasted
Efficiency Split
Energy Comparison
  • Kettle (Actual)
    0.1163 kWh
  • Induction (Optimal)
    0.0349 kWh
Induction assumes boiling only the needed amount.
Time to Boil
190.0s
Kettle (Full Volume)
59.0s
Induction (Needed Only)
Did you know?

Standard electric kettles often have a minimum fill line (e.g. 500ml). If you only need one cup (250ml), you are forced to boil double the amount! High-speed induction hobs allow you to heat exactly what you need in a small pot, often faster than a kettle.

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Frequently Asked Questions

Boiling more water than you need is a major source of energy waste. For a household that regularly boils double the necessary amount, this can add up to 15-25 euros per year in unnecessary electricity costs.

For very small amounts (like a single 250ml cup), an induction hob can be more efficient if your kettle has a high minimum fill level (e.g. 500ml). Induction heats exactly what you need with almost no standby loss.

Generally, a larger kettle allows you to boil more at once, but it also tempts you to overfill. Using a smaller 1-liter kettle for small households can lead to more mindful water usage.

Always use the measurement marks on the side or fill your cup first and pour that amount into the kettle. Also, descaling your kettle regularly prevents lime scale from insulating the heating element.

Usually no. While gas is cheaper per unit of energy, gas stovetops are only about 40%% efficient (most heat escapes around the kettle). Electric kettles and induction hobs are over 85%% efficient.

Yes, PlAnhead tools are free and privacy-focused. All calculations happen in your browser.
Verified Tool Facts & Data Sources
Calculates TCO based on VDI 2067 standards.
Uses current energy price benchmarks.
Compares Electric Kettle vs. Induction Stove.
Privacy-first: No data leaves your browser.
Machine-readable facts available at /facts.json

Detailed Methodology & Calculation Logic

Energy Calculation Logic

The calculator uses the specific heat capacity of water to determine the energy required to reach boiling point (100°C).

  • Heat Capacity: We use a constant of 1.163 Wh per kilogram per Kelvin (Wh/kg·K).
  • Temperature Delta: Calculated as the difference between the starting temperature (default 15°C) and the boiling point (100°C).
  • Efficiency Factor: Kettle heating elements are typically 85% efficient, while induction hobs are around 90%. This accounts for heat lost to the vessel and the surrounding air.
Waste & Cost Analysis

Waste is calculated by comparing the volume of water you actually need for your beverage vs. the total volume boiled.

  • Energy Waste: The energy required to heat the 'excess' water is calculated separately using the same thermodynamic formulas.
  • Annual Impact: We multiply the daily waste by 365 days and your local electricity price (per kWh) to show the hidden cost of over-filling.
  • Time Efficiency: Boiling time is derived from the wattage (P) and energy (E) using the formula: t = (E × 3600) / P.
Last updated: 2026-03-26