DC Power Calculator
Calculate DC power, energy and running cost from voltage and current.
About DC Power Calculator
DC power is a straight product of voltage and current with no power factor to consider. Amp-hours are shown because battery capacity is specified in charge rather than energy. Sizing a battery needs amp-hours at the system voltage, not watt-hours, which is why both are given.
Formula
DC Power
P = V I; energy = P × hours
- Ah
- Amp-hours, the charge measure used for battery sizing
Worked example
With the default values below, DC Power Calculator returns DC Power of 60.000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- DC voltageminimum 0 V
- 12 V
- Currentminimum 0 A
- 5 A
- Hours of operation per dayaccepts 0–24 h
- 6 h
- Energy price per kWhminimum 0
- 0.15
Results
- DC Power
- 60.000 W
- Daily Energy
- 360.00 Wh
- Monthly Energy
- 10.8000 kWh
- Monthly Running Cost
- $1.62
- Charge Consumed per Day
- 30.000 Ah
Step by step
- 1Values used
- 2DC Power
- 3DC Power= 60.000 W
- 4Daily Energy= 360.00 Wh
- 5Monthly Energy= 10.8000 kWh
- 6Monthly Running Cost= 1.62
- 7Charge Consumed per Day= 30.000 Ah
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is DC Power calculated?
P = V I; energy = P × hours DC power is a straight product of voltage and current with no power factor to consider. Amp-hours are shown because battery capacity is specified in charge rather than energy.
Why does DC Power matter?
Sizing a battery needs amp-hours at the system voltage, not watt-hours, which is why both are given.
What values do I need to enter?
This calculator takes 4 inputs: DC voltage, Current, Hours of operation per day, Energy price per kWh. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.