Estimate kW, kVA, line current, voltage, and power factor for balanced three-phase electrical systems. IEEE Std 141 formulas. Free tool — no login required.
Live Tool
Enter voltage, current, and power factor — or choose what you want to solve for. The calculator shows all key values with the full formula trace.
About This Calculator
This calculator can help estimate important three phase electrical values for balanced systems, including kilowatts (real power), kilovolt-amps (apparent power), line current, line-to-line voltage, power factor, and basic load demand.
These values are important when reviewing electrical loads, checking equipment capacity, planning transformer size, estimating generator requirements, or preparing early data for a power system study.
The calculator uses standard IEEE three phase power formulas. The main formula for three phase real power is:
A higher power factor means the system is using electrical power more efficiently. A lower power factor means more reactive power is present, which can increase system losses and reduce available capacity.
Use Cases
Use this calculator during early electrical planning, equipment review, or load estimation. It is helpful when checking three phase systems before moving into detailed engineering calculations.
Three phase power is more efficient than single phase power for larger electrical loads. It provides smoother power delivery, supports heavy motors, and is widely used in commercial and industrial electrical systems. Understanding three phase power helps users make better decisions about load capacity, equipment selection, and system planning.
FAQ
Common questions about the three phase power calculator and how to use it.
A Three Phase Power Calculator is an electrical calculator used to estimate kW, kVA, current, voltage, and power factor in a balanced three phase electrical system. It uses IEEE standard formulas to produce accurate preliminary results.
The common formula for three phase real power is kW = √3 × Voltage × Current × Power Factor ÷ 1000. The formula for apparent power is kVA = √3 × Voltage × Current ÷ 1000. These are the IEEE Std 141 standard formulas for balanced three phase systems.
kW is real power — the usable power doing actual work. kVA is apparent power, which includes both real power and reactive power. The relationship between them is determined by the power factor. kW = kVA × Power Factor.
Yes, it can help with early transformer load estimates. However, final transformer sizing should consider demand factors, load type, future expansion, NEC code requirements, and a licensed engineering review. This tool is for preliminary planning only.
No. This calculator is for preliminary calculations only. Final electrical design, utility submissions, and safety-critical decisions should be reviewed by a licensed professional engineer or qualified power system engineering team.
You can enter any three phase line-to-line voltage. Common values include 208V, 240V, 400V, 415V, 480V, 600V, 4,160V, and 13,800V. The calculator works for any voltage as long as the system is a balanced three phase configuration.
Professional Engineering
If your project involves large electrical loads, transformers, switchgear, generators, substations, renewable energy systems, or utility interconnection, a detailed power system study is recommended.
Our engineering team provides detailed power system studies, equipment review, protection coordination, and technical documentation for utility-scale projects across North America.
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This Three Phase Power Calculator provides preliminary estimates only. It does not replace a professional electrical design, stamped engineering calculation, load flow study, short circuit study, arc flash study, or protection coordination study. For final design, utility submission, equipment sizing, code compliance, or safety critical decisions, consult a licensed professional engineer or qualified electrical engineering team.
