How to Use This Tool
Convert line voltage, current and power factor into input power and running cost. Calculate balanced three-phase kW, kWh, apparent power and energy cost from editable electrical and tariff assumptions.
The decision this tool supports
Multiplying volts by amps without √3 or power factor can materially overstate or understate a balanced three-phase load. This page keeps the decision bounded to real input power and the supporting outputs shown beside it. Three-Phase Energy does not import an account, infer a market rate, or silently substitute an industry average.
Inputs and units
The Three-Phase Energy calculation uses Line-to-line voltage, Line current, Power factor, Operating time, Energy price. Keep all money values in one currency and all time, distance, mass, energy or volume entries in the unit printed beside the field. Mixing Three-Phase Energy scopes can produce a plausible number with the wrong meaning.
- Line-to-line voltage is entered in V.
- Line current is entered in A.
- Power factor is entered in decimal.
- Operating time is entered in hours.
- Energy price is entered in currency/kWh.
Formula and worked check
Balanced three-phase real power kW = √3 × line-to-line volts × line amps × power factor ÷ 1,000; energy = kW × hours. At 400 V, 20 A and 0.9 power factor, input is 12.47 kW; eight hours uses 99.77 kWh and costs $14.96 at $0.15/kWh. The Three-Phase Energy default is an executable known-answer case, not a benchmark or recommendation. Change one input and verify that the direction of real input power still matches the stated relationship.
How to interpret the result
Use measured line values and the applicable tariff for an energy-only estimate; demand charges can dominate a commercial bill. The additional Three-Phase Energy outputs expose the denominator, comparison, capacity or reverse value needed to audit the primary result instead of presenting one unexplained number.
Assumptions
- Voltage is RMS line-to-line and current is representative line current.
- Power factor is entered as a decimal from zero to one.
- Energy price is user supplied.
Save the Three-Phase Energy input values and date with any material decision. A later Three-Phase Energy rerun is reproducible only when the same assumptions and units are available.
Limitations and safety boundary
This assumes a balanced sinusoidal load and excludes efficiency, harmonics, phase imbalance, demand charges, taxes and reactive-energy penalties. Three-Phase Energy is an estimate and cannot replace a contract, local code, licensed professional, calibrated measurement, lender statement or platform report where one governs the decision.
Source and privacy
The Three-Phase Energy definition or rule was checked against U.S. Department of Energy — Motor systems guidebook on 2026-08-26. Recheck U.S. Department of Energy — Motor systems guidebook when a specification or policy behind Three-Phase Energy can change. Three-Phase Energy arithmetic runs in this browser tab; ecech does not receive the values through a calculation API.
Sources & assumptions
Tool Spec v2 · verified 2026-08-26. Platform rules and fees can change; the editable inputs remain authoritative for your account.
Official references
- U.S. Department of Energy — Motor systems guidebook (checked 2026-08-26)
Model assumptions
- Voltage is RMS line-to-line and current is representative line current.
- Power factor is entered as a decimal from zero to one.
- Energy price is user supplied.
- This assumes a balanced sinusoidal load and excludes efficiency, harmonics, phase imbalance, demand charges, taxes and reactive-energy penalties.
