Calculate Power from Voltage and Current

Who it’s for

Energy managers, building operators, electrical engineers, and dashboard authors whose meters or sensors report voltage and current but not power — when the multiplication would otherwise be redone in every widget binding, alarm threshold, and aggregation.

What it does

Multiplies the latest voltage and current telemetry on every update and emits the result as power:

Once power is published, downstream consumers — alarms, dashboards, and other calculated fields — can read it directly. The result is in volt-amperes (VA).

How to customize

• To use this on different meter keys — change the Time series key on the voltage and current arguments (e.g. voltage → phaseVoltage, current → lineCurrent).
• To rename the output — change the output Time series key from power to your domain key (e.g. apparentPower).
• To rescale the output — change the Expression to divide by 1000 so the value is published as kVA instead of VA, or apply any unit conversion factor.
• To change the output precision — adjust Decimals by default on the output to whatever precision your dashboards and alarms need.
• To timestamp the result with the latest argument reading instead of server time — enable Use latest timestamp. The output’s ts then becomes the max across all non-default input arguments, matching when the source actually updated. Useful for LoRaWAN, batched uploads, or any source where reading time lags wall-clock.
• To use a different fallback when no data has arrived — change Default value on each argument (defaults to 0).

See also

For loads with a non-unity power factor (motors, inverters, three-phase industrial), apparent VA overstates real consumption. Use the template that takes voltage, current, and cosPhi and returns active (W), reactive (VAR), and apparent (VA) power as three separate outputs:

Active and Reactive Power Calculation verified Dmytro Shvaika