Calculation reviewed: 4 October 2026 · Engineering Desk Tools
How to use the Energy & running cost calculator
Estimate energy consumption and cost from average electrical input power and operating time. Start with measurements or documented values for the equipment and reporting period you actually want to assess. The calculator does not fill in a typical installation for you. Its blank fields help keep a demonstration value from being mistaken for your own operating data.
Choose the required options, enter the values in the labelled units and select Calculate. If a field is rejected, check its range and unit before changing it. The result is accompanied by the equation and assumptions so you can decide whether it answers your engineering question.
Inputs and measurement basis
- Average input power (kW). Average input power while running, from a meter if possible.
- Operating hours / day. Hours the equipment runs on a typical day. The allowed maximum is 24.
- Days. Number of operating days in the period.
- Tariff / kWh (your currency). Price per kWh from your tariff, excluding demand charges.
Record the measurement source and operating condition. Retain unrounded values for verification.
Method and interpretation
Use the average input power over the operating period, rather than maximum nameplate power. Equipment that cycles, unloads or changes speed may use substantially less or more energy than a simple duty estimate suggests. Where possible, obtain kWh from a meter and compare that reading with the estimate over the same interval.
Energy = input kW × hours/day × days. Cost = energy × tariff/kWh.
Use actual average input power, not motor shaft rating. Excludes demand charges, fixed fees, taxes and changing tariffs. The cost uses the currency of your entered tariff.
Worked example
This example does not populate the form. Enter your own installation data.
Calculated result: 1,200 kWh and 240 in the tariff currency. Cost uses the currency of your entered tariff.
Check the arithmetic independently using the displayed equation. Retain intermediate precision and compare the final value with your equipment documentation.
Quick-reference table
These illustrative rows retain the worked example assumptions except for the varied input. They are not certified ratings or manufacturer data. Use the form for intermediate values.
Common mistakes
Multiplying a daily total by hours again; confusing kW with kWh; treating this tariff-only estimate as the full electricity invoice. Before relying on the output, check the decimal format, unit scale and source of each value. Recheck unusual results against the formula.
Frequently asked questions
Are the example values used automatically?
No. Inputs remain blank when the tool opens or when you clear them. The worked example and table are reading material below the calculator. Enter the actual values you want to check each time, and label saved reports so their context is not lost.
What does the result mean?
The result is the energy used and its cost for the average power, hours, days and tariff entered. Compare it with a meter reading or invoice, which may include demand charges and fees that are not modelled here.
Can I use a zero or a negative value?
The allowed range follows the meaning of each input. A divisor needs a positive value; other fields may allow zero. Check the form labels and error message rather than forcing an invalid value. A rejected input must be corrected before a result can be shown.
Is this a final design or equipment approval?
No. Use actual average input power, not motor shaft rating. Excludes demand charges, fixed fees, taxes and changing tariffs. The cost uses the currency of your entered tariff. Use the calculation as support for a checked decision, and review equipment documentation and applicable requirements before changing an installation or operating setting.
How can I save or share a calculation?
Calculate first, then use Copy result or Print report. Some maintenance tools also provide a CSV summary. Reports contain your own entered data, so review them before sharing. You can share the public page URL without including plant records or confidential measurements.
How do I report an unexpected result?
Use the Contact page and include the tool URL, input values, units, expected output and the reference you used. Explain the measurement basis. Exclude confidential information.
Related tools and records
Use related calculations with consistent units, periods and equipment scope.
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