Home Electricity Consumption Estimator
Select your appliances, adjust hours and tariff, and see your estimated electricity cost.
How this is calculated
Each appliance's daily energy use is watts × quantity × hours per day, converted to kilowatt-hours. Monthly and annual figures scale that up by 30 and 365 days respectively, and cost multiplies kWh by your tariff. The breakdown table is sorted by annual consumption so you can see your biggest contributors at a glance.
This calculator covers appliances while actively in use, but standby power — devices left plugged in and drawing a small trickle of electricity even when "off" — can account for an estimated 5–10% of a typical home's electricity bill. Games consoles, set-top boxes, phone chargers left plugged in, and older TVs are commonly among the worst offenders, since many never fully power down. To compare your estimated cost against your country's typical tariff, see the Home Electricity Cost by Country calculator; for backup power planning, see the Generator Size calculator; and for the underlying power formula behind any appliance's wattage, see the Electrical Power calculator.
Frequently asked questions
- Where do the default wattages come from?
- Typical wattages for common household appliances. Your own appliances may draw more or less — check the rating label or manual and adjust the wattage field if you know the exact figure.
- What does "quantity" mean?
- How many of that appliance you have running — most useful for lighting, where you might have several rooms each with their own LED lighting load, but available for any appliance.
- Why do appliances like fridges run 24 hours a day?
- A fridge's compressor cycles on and off to maintain temperature, but averaged out it's genuinely drawing power continuously — unlike something like a kettle, which only draws its full wattage for the few minutes it's actually boiling.
- Can I use this in my own app?
- Yes — every calculator on Stupidly Clever has a matching REST API and MCP tool that runs the same underlying logic.
- How is electricity consumption calculated?
- Each appliance's energy use is watts × quantity × hours per day, converted to kilowatt-hours (divide by 1,000). Summing across all selected appliances gives daily consumption, which is scaled up to monthly and annual figures and multiplied by your tariff for cost.
- What appliances use the most electricity?
- Appliances that either draw high wattage or run for long hours dominate — electric ovens and EV chargers draw a lot of power but usually for short periods, while fridges draw modest power but run continuously (24 hours/day), often making them one of the largest contributors to a home's baseline electricity use.
- What is a kilowatt-hour?
- A kilowatt-hour (kWh) is the standard unit electricity bills are measured in — the energy used by a 1,000-watt device running for one hour. It's what you're actually charged for, not the wattage of any single device.
- How do I reduce my electricity bill?
- Focus on your highest-consumption appliances first (shown in the breakdown table above), since reducing hours or upgrading to more efficient models has the biggest absolute impact there. Beyond individual appliances, addressing standby power draw across many small devices can also meaningfully lower a bill — see below.