Electrical & digital · Calculator companion · By K Imports
Single & three-phase AC power: practical guide
This guide explains how to use the Count.ie single & three-phase ac power. Compute real, apparent and reactive power for a balanced AC load. Follow the inputs, method and worked example below, then compare your own scenario.
Guide written .
Open the Single & three-phase AC power calculatorWhat to prepare
- Record the device or system specification and relevant units.
- Identify whether values are nominal, measured or assumed.
- Check model assumptions such as steady conditions, power factor or ideal throughput.
Understand the inputs
The calculation method
Single phase: S=VI; balanced three phase: S=√3VI; P=S×PF; Q=√(S²−P²).
Worked example
Illustrative inputs and their result.
Example inputs
- RMS voltage / line voltage (V)
- 230
- RMS current / line current (A)
- 16
- Power factor
- 0.95
- Balanced three-phase load
- No
Calculated example result
- Real Power KW
- 3.496 kW
- Apparent Power KVA
- 3.68 kVA
How to interpret the result
A formula result is not a safety approval or an installation design. Electrical work and other safety-critical systems need appropriately qualified assessment.
Change one specification at a time while keeping the operating assumptions constant. Verify practical limits against the equipment documentation before acting.
Common mistakes to avoid
- Do not mix bits with bytes or electrical quantities with different units.
- A theoretical maximum is not a guaranteed real-world operating value.
- Do not apply a simplified model outside its stated conditions.
Assumptions and sources
Editable inputs are planning assumptions; check the method and result notes for scope.
If your case falls outside this scope, use a more suitable calculator or contact us about an unclear method.