# Energy Consumption Calculator

> Calculate energy consumption step by step: E = P_rated × load factor × hours/day × days/year.

Page: https://freecalculator.tech/tools/energy-consumption-calculator
Last reviewed: 2026-11-03

## Formula

E = P_rated × load factor × hours/day × days/year.

- Load factor is entered by you — no typical value is assumed.
- Hours ≤ 24 and days ≤ 366.
- For HVAC, compressors cycle, so use a measured or estimated average.
- E = P_rated × load factor × hours/day × days/year.
- Inputs used: Rated power, Average load factor, Operating hours per day, Operating days per year.

## Inputs

- Rated power
- Average load factor
- Operating hours per day
- Operating days per year

## Annual energy consumption formula

Energy (kWh) = rated power (kW) x load factor x hours per day x days per year. The load factor is the average share of rated power the equipment actually draws.

## Estimating the load factor

A plug-in energy meter or logged reading over a typical period gives the real average draw. Dividing that by the rated power gives the load factor. Using 100% assumes the equipment always runs flat out.

## From kWh to cost

Multiply annual kWh by your own electricity price per kWh. Prices vary by supplier, tariff and time of day, so none is built in.

## Worked example: 2 kW equipment

1. Daily = 2 x 75% x 10 h = 15 kWh
2. Annual = 15 x 300 days = 4,500 kWh
3. Monthly average = 4,500 / 12 = 375 kWh

## Common questions

### What is load factor?

The average power drawn as a share of rated power. A compressor running half the time at full power has about a 50% load factor.

### How is this different from the energy calculator?

This one works per year with a load factor for equipment; the energy calculator uses a direct average power over days.

### How do I get cost?

Use the equipment energy cost calculator with your own tariff.

### How do I use the Energy Consumption Calculator?

Enter the required values for Rated power, Average load factor, Operating hours per day, Operating days per year. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.

### What formula does the Energy Consumption Calculator use?

E = P_rated × load factor × hours/day × days/year. The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.

### Can the Energy Consumption Calculator be used for exact decisions?

Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.

## Limitations and assumptions

- Single average load factor.
- Standby consumption excluded unless included in load factor.
- No seasonal variation.
- Results are estimates for planning and learning. Real designs, installations and bids must be checked by a qualified, licensed professional against the codes that apply where you work.
- The result depends on the values you enter for this energy consumption calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.

## Sources

- OpenStax — https://openstax.org/books/college-physics-2e/pages/7-7-power

## Cite this page

- APA: Free Calculator. (2026, November 3). Energy Consumption Calculator. https://freecalculator.tech/tools/energy-consumption-calculator
- MLA: "Energy Consumption Calculator." Free Calculator, 3 Nov. 2026, https://freecalculator.tech/tools/energy-consumption-calculator.
- Link: Energy Consumption Calculator — Free Calculator, https://freecalculator.tech/tools/energy-consumption-calculator