Calculadora de consumo elétrico
The detailed guide below is currently available in English.
Watts, hours, and kilowatt-hours
A watt is a rate, not an amount; utilities bill for energy, which is rate multiplied by time. Run a 1,500 W space heater for four hours and it consumes 1,500 × 4 = 6,000 watt-hours, or 6 kWh. Multiply the kilowatt-hours by your rate — 6 kWh at $0.15 is 90 cents — and the cost of comfort becomes concrete.
Finding the inputs on real devices
Nameplate watts are usually printed on the label near the serial number or listed in the manual. Your rate is on the utility bill as cents per kWh; a $0.15 entry matches a 15¢ rate. When a device idles between cycles, estimate honestly — a fridge rated at 150 W that actually compresses a third of the time costs a third of the round-the-clock figure.
Perguntas frequentes
How much does it cost to leave something on all day?
Enter 24 for hours per day. A 60 W bulb burning around the clock at $0.15 per kWh uses 1.44 kWh daily, about $5.26 per 30-day month — often more than the bulb itself cost.
Should I use the watts on the label or a power meter?
The label gives the maximum draw, which suits heaters and incandescent loads that run flat out. Electronics with standby modes and fridges with compressors vary, so a plug-in power meter over a full day gives the truer average.
Why use 30 and 365 days instead of exact months?
Utility billing periods rarely line up with calendar months, so the industry convention of 30-day months and 365-day years keeps comparisons consistent. Multiply daily figures by the actual days in your bill for a closer match.