Three-Phase Power Calculator
Estimate single-phase or balanced three-phase electrical power from voltage, current and power factor.
Currency selection changes the unit label, not an exchange rate. Enter every price in the selected currency.
How to choose the inputs
For a typical 230/400 V system, use 400 V between phases in the three-phase formula and 230 V phase-to-neutral for a single-phase load. Current is per phase; do not add three phase currents and insert that total. Power factor is a ratio, not efficiency.
Formula and measurement boundary
Three worked scenarios
These are fixed hypothetical examples, not live tariffs or verified product data. They use EUR and kilometres where applicable and do not change with the form settings. Only the table input changes.
Unchanged inputs
- Supply type: Three-phase
- Voltage: 400 V
- Power factor: 1
| Current per phase | Estimated result |
|---|---|
| 10 A | 6.93 kW |
| 16 A | 11.09 kW |
| 32 A | 22.17 kW |
At a power factor of 1, doubling current doubles active power. If power factor were 0.8 instead, each result would be 20% lower at the same voltage and current.
What this result does not establish
- The three-phase calculation assumes balanced loads.
- The output is active kW, not apparent kVA when power factor differs from 1.
- This does not select cables, breakers or permissible continuous current; installation design requires a qualified electrician.
Total three-phase power can hide a limit on one phase
The following are additional hypothetical decision examples. Separately discussed fees, reserve allowances or running costs are not automatically added to the form result.
For a balanced illustrative 400 V three-phase supply at 16 A and power factor 1, power is √3 × 400 × 16 ≈ 11.09 kW. This is a balanced-load calculation. A single-phase 230 V appliance at 16 A draws about 3.68 kW and uses the capacity of one phase, not one third of an automatically interchangeable total.
Suppose a three-phase EV charger draws 10 A on each phase and a heater draws another 10 A on phase L1. L1 now carries 20 A while L2 and L3 carry 10 A each. A total-power comparison can look acceptable even though L1 exceeds a hypothetical 16 A phase limit. Load balancing must observe the individual phases, not only the sum.
Use the real line-to-line voltage, current and power factor for the question being asked. This calculator does not size cables, select protection, establish continuous permissible current or account for every installation condition. Have the phase allocation and protective devices checked before increasing a charger setting. A breaker label alone is not a complete circuit design.
Sources and their scope
- Schneider Electric: apparent power — Single-phase and balanced three-phase relationships.
These reference pages were accessed on 21 September 2026. The equations and examples are the site’s own model; these sources do not certify its defaults or results.
Frequently asked questions
Does a 16 A three-phase supply mean 48 A in one cable?
No. The input describes 16 A in each phase under the balanced assumption.
Can I use this for a motor shaft rating?
This calculates electrical input power. Mechanical output would also depend on motor efficiency.
Read the model and verification limits