The cheapest way to boil water is usually an electric kettle, but the stove and microwave are close behind. This guide calculates the cost of boiling one liter (about 4 cups) by each method from physics, commonly cited efficiencies and EIA energy prices. It is a calculation, not a hands-on test.
Check today’s price on Amazon: Cosori Electric Kettle
Quick Answer: Cheapest Way to Boil Water
- Every method costs only a few cents per liter, so the difference is small.
- An electric kettle costs about 2¢ per liter; an induction burner is close behind; the microwave costs more because it is less efficient at heating water.
- Gas is competitive per liter at the EIA August 2026 price of $27.05 per thousand cubic feet, but heats water less efficiently.
- Use only as much water as you need.
📊 The number that matters
Heating one liter of water by 85°C needs about 0.099 kWh before losses. What changes the cost is how efficiently each appliance delivers that energy.
Cost to Boil One Liter by Method
Efficiencies are commonly cited figures (electric kettle about 90%, induction about 84%, electric coil about 74%, microwave about 55%, gas about 40%) and are assumptions, not measurements. Electricity is 18.16¢/kWh (EIA, August 2026); gas is $27.05 per thousand cubic feet at about 1,037 Btu per cubic foot.
Cost to heat 1 liter from 59°F to boiling. Calculated from assumed efficiencies, not measured.
What the Numbers Say
All five methods land between about 2¢ and 3.3¢ per liter, so none is expensive. The kettle wins because most of its energy goes straight into the water. Gas is cheap per unit of energy but loses a lot of heat around the pot.
Practical Tips
Boil only the water you need, put a lid on the pot, and use an electric kettle for tea and instant foods. Use the microwave only for a single cup in a microwave-safe container.
Related Costs
For longer cooking, burner choice matters more than boiling. See our guide to induction cooktop running costs.
See the latest deal on Amazon: Cosori Electric Kettle
For more detail, see our guides to what it costs to boil a kettle and appliance wattages and running costs.
Black Friday and Cyber Monday Electric Kettles Deals
Black Friday and Cyber Monday 2026 deals on electric kettles are coming — bookmark this page and check back from 27 November for live price drops.
FAQ
Is it cheaper to boil water in the microwave or on the stove?
Per liter, a stove burner is usually cheaper than a microwave at the assumed efficiencies above, but the differences are a cent or two.
Is gas cheaper than electricity for boiling water?
It depends on local prices. At the national averages quoted here, a gas burner is about the same as an electric kettle per liter.
Sources: U.S. Energy Information Administration, Electric Power Monthly (August 2026 residential average, 18.16¢/kWh). EIA natural gas price, August 2026. Specific heat of water. Appliance efficiencies are commonly cited approximations. As an Amazon Associate we earn from qualifying purchases.