⚡ Energy Consumption Calculator

This is a consumption-first calculator: it answers "how much energy do I use?" (in kWh), not "how much does it cost?". Knowing your consumption first helps you spot the biggest users before worrying about prices. If you want the cost, enter your kWh totals into our energy cost calculator, which multiplies kWh by your tariff.

kWh = watts x hours per day x (duty cycle / 100) / 1000. Daily kWh is multiplied by days per week for the weekly figure, weekly x 52 for the yearly figure, and weekly x 52/12 for the monthly figure (one month = 52/12 weeks). Every device row uses the same formula, so the household total is simply the sum.

These are estimates built from nameplate watts (the maximum rating printed on the device) multiplied by your usage hours. Real devices rarely draw nameplate power continuously: motors cycle, chargers taper, and "off" devices can still sip standby power. For a measured number, read your utility meter over a week or use a plug-in power meter, then compare.

Duty cycle is the percentage of the "on" hours that a device actually draws power. A refrigerator plugged in 24 hours a day may only run its compressor about 40% of the time, so its effective consumption is 150 W x 24 h x 40% = 1.44 kWh per day, not 3.6 kWh. Leave it at 100% for devices that draw full power the whole time they are on, like kettles and toasters.

In most homes the biggest consumers are heating and cooling (space heaters, air conditioners), electric water heating, and clothes dryers — all draw thousands of watts. Electronics like TVs, laptops, and phone chargers use far less individually. The ranking bars above show exactly where your household's kWh goes, which often surprises people.

No — they are typical nameplate values so you can estimate quickly. Two "1500 W" space heaters from different brands can draw slightly different power, and inverter appliances vary with load. For the most accurate estimate, read the watts printed on your device's label (or its manual) and type that number into the watts field instead of using the preset.

Start with the top of your ranking: cutting one hour a day off a 1500 W device saves about 45 kWh a month. Other proven moves: switch remaining incandescent bulbs to LEDs (about 75% less energy for the same brightness), unplug chargers and use switched power strips for standby loads, wash laundry cold and air-dry when possible, and set water heaters and thermostats a few degrees lower.

A unit converter translates between energy units (kWh, joules, BTU, calories) — it converts a number you already have. This calculator estimates the number in the first place from your appliances and usage habits. If you need to convert the resulting kWh into other units, use our energy unit converter.