Kilowatt Calculator — Direct Current Power Supply System
Determine direct-current electrical power in kilowatts from DC voltage and current, or enter any two variables to solve for the third.
US + metric
Formula shown
Shareable results
Kilowatt — Direct Current
kW
V DC
A DC
Kilowatts0.96kW(960 W)
Electrical power (E × I)
960 W
Electrical power
0.96 kW
Formula & method
kW = E · I / 1000
For a steady direct-current supply, electrical power in watts is DC voltage times DC current. Divide by 1000 for kilowatts. There is no AC power-factor or phase term, and no efficiency term because the result is electrical input power rather than mechanical output.
Assumes a steady direct-current supply with voltage and current measured at the same operating point. For preliminary and educational use; verify against equipment data and applicable electrical codes.
This calculator determines electrical load power for a direct-current supply. Enter any two of kilowatts, DC voltage, and DC current to calculate the third.
The formula
kW = E · I / 1000. DC voltage multiplied by DC current gives electrical power in watts; dividing by 1000 converts watts to kilowatts. Unlike an AC calculation, the steady-DC relationship has no power-factor or phase multiplier.
Solve in any direction
Kilowatts — the DC electrical power drawn at a known voltage and current.
Voltage — the DC supply voltage required for a known power and current.
Current — the DC amperage required for a known power and voltage.
Kilowatts here mean electrical input power
The result is the electrical power supplied to the load. It does not include an efficiency term and is not automatically the mechanical shaft output of a motor. For DC motor output, use the DC motor horsepower calculator with an appropriate efficiency.
Steady-DC assumption
The direct product E · I assumes substantially steady voltage and current at the same operating point. Where a converter, rectifier, or switching load creates significant ripple, determine average real power from the average of instantaneous v(t) · i(t). Multiplying separate average voltage and current readings can be inaccurate when their ripple is correlated.
Worked example
A 48 V DC load drawing 20 A uses 48 × 20 = 960 W, or 0.96 kW.
DC electrical power relation (P = E × I)SI watt and kilowatt definitions
Verified
Constants and formula two-source checked (PumpCalcs engineering review, 2026-08-25).
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