Units and formulas used in calculators
Enter the power in watts, the planned daily operating hours in hours, and the percentage of operation in seconds. Estimated electricity consumption = Power ÷ 1000 × Daily hours × Number of days × Percentage ÷ 100; Cost = Estimated electricity consumption × Price per kilowatt-hour. All prices are entered by you; the tool does not automatically retrieve electricity prices for a specific region.
For example, 1000 W, 2 hours per day, 30 days, 100% usage would result in 60 kWh. If the input electricity price is 0.6, the cost would be 36 units of currency. This is a calculation example, not a real-world test of a specific device, nor does it reflect the current local electricity price.
When can't the rated power be used directly?
Electric kettles operate near-continuous heating, unlike refrigerators and air conditioners with thermostats. The power rating on the nameplate does not represent the device's constant operating power; start/stop, speed setting, temperature, load, and standby mode can all alter average power consumption. The percentage of operation only allows you to explicitly state an assumption; it cannot automatically infer the actual percentage.
If there is a power meter or verifiable device to record the data, observe a representative time period, record the total power consumption and duration, and then check for estimation errors. If no measurement data is available, make scenario comparisons using different percentages, label the results as estimates, and do not directly replace the bill.
How to fairly compare the two options?
When comparing A and B, first ensure that the number of days, electricity price, and service demand remain consistent. For example, compare two plans with the same daily usage time but different power outputs. Then, change the number of hours or the percentage of operation individually and observe the difference; changing all conditions at once can easily lead to confusion about the causes.
The calculator displays two sets of battery consumption, cost, and the difference between B and A. A negative difference indicates that B has a lower estimated cost. Whether it's worthwhile to replace the device also involves purchase cost, lifespan, and user experience; the battery consumption difference on this page alone cannot answer that question.
Use input checks to prevent miscalculations.
The number of hours per day must be between 0 and 24, the number of days between 1 and 366, and the percentage between 0 and 100. Power consumption and electricity price cannot be negative. Blank values must be padded to avoid being automatically treated as zero. A zero percentage of operation results in zero operating power consumption, but this does not mean that the actual device has no standby power consumption.
Tiered pricing, peak-valley pricing, basic fees, and other charges are not included in the first version of the model. When encountering these billing methods, calculations should be made based on actual time periods or according to the billing rules of the electricity service provider. Do not use a uniform average price to mask changes in billing conditions.