Electrical Load Calculator
Estimate apparent current demand from total connected watts, voltage and power factor.
Interactive Electrical Calculator
Electrical Load Calculator
Estimate apparent current demand from total connected watts, voltage and power factor.
Result
Enter values and calculate.
About the Electrical Load Calculator
The Electrical Load Calculator handles total power and load calculations across single-phase, three-phase and AC systems without needing a spreadsheet, app download or manual lookup table. Estimate apparent current demand from total connected watts, voltage and power factor. Three-phase and single-phase power formulas differ by a √3 factor, and mixing them up is one of the most common load-calculation mistakes.
It's aimed at electricians sizing panels and services, and engineers estimating total connected or demand load, who need a fast, reliable number without redoing the math by hand each time.
How the calculation works
Here is the relationship the calculator solves for you:
I = P / (V × PF) or P / (√3 × V × PF).
Where each input maps to a field in the calculator above:
- Total Connected Load in W.
- Voltage in V.
- Power Factor.
- System — choose between DC, Single Phase, Three Phase.
Every one of these values can be edited above, and the calculator updates the result the moment you press Calculate.
A worked example
For example, start with 5000 W for total connected load, 230 V for voltage and 0.9 for power factor. That's a reasonable starting point to explore from: nudge one value up or down and watch how much the result shifts before you commit to a final design figure.
When to use the Electrical Load Calculator
Typical reasons people reach for the Electrical Load Calculator:
- Estimating total connected load for a new panel or service.
- Comparing single-phase and three-phase power for the same voltage and current.
- Checking a load calculation against a utility service size before requesting an upgrade.
- Sizing equipment for a workshop, small commercial space or off-grid system.
Good practice: Diversity and demand factors are usually applied on top of a simple connected-load sum for realistic panel and service sizing.
Also worth knowing: Real power (W) is what actually does work; apparent power (VA) includes the extra current caused by a lagging or leading power factor.
Frequently asked questions
What does the Electrical Load Calculator calculate?
Estimate apparent current demand from total connected watts, voltage and power factor.
Is the result exact enough to build from?
The formula above is applied exactly to the values you enter, so the math itself is precise. Real-world results can still differ due to component tolerances, temperature, installation method, equipment efficiency and local code requirements, so treat the output as a strong planning estimate and verify final designs against manufacturer data and the electrical code that applies to your installation.
Does this calculator store or send my data anywhere?
No. The Electrical Load Calculator runs entirely in your browser, and nothing you type is transmitted or stored anywhere.
What happens if I get this wrong?
Underestimating total connected load leads to a panel or service that is undersized from day one; overestimating wastes money on oversized equipment.
What should I do if the result looks off?
The Electrical Load Calculator works on any modern browser, phone or desktop, and recalculates as soon as you press Calculate. If a result looks off, double-check that every field is filled in with the unit shown next to it (mixing up units, such as W with kW, is the most common cause of an unexpected answer) and re-enter the values.