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Free Electrical Load Calculator for a Home

Add up your appliances to see connected load, likely running load, current and monthly units.

This helps you plan and talk to an electrician. It does not replace one. A licensed electrician must size the wiring, breakers and earthing. Wrong wiring can cause fires and fatal shocks.

Your appliances

Change the watts to match the label on your appliance. Set the number to 0 for what you do not have.

ApplianceWattsHow manyHours a day

Check your bill. Slabs and fixed charges differ by state and supplier.

Connected load
0 kW
Likely running load
Current at that load
Main breaker, a starting point
Units a month, about
Energy cost a month, about

Your sanctioned load is on your electricity bill. If this comes out higher, ask your supplier how to raise it.

How the load is worked out

Connected load = the watts of everything added together. It is rarely all on at once, so likely running load = connected load × the share running at once.

Current: single phase, amps = watts ÷ (230 × 0.9). Three phase, amps = watts ÷ (1.732 × 415 × 0.9). The 0.9 is an assumed power factor.

Main breaker, as a starting point: the next standard size above current × 1.25 (6, 10, 16, 20, 25, 32, 40, 50, 63 A).

Units: one unit is one kilowatt-hour. Watts × number × hours × 30 ÷ 1,000 gives the units in a month.

Example: a home with 5,500 W connected and 70% running has a likely load of 3,850 W. That is 18.6 A on single phase, and 18.6 × 1.25 is about 23 A, so the starting point is a 25 A main breaker.

The watts shown are rough figures. Hours for a fridge or AC mean the time its compressor runs, which is less than the time it is switched on.

Questions people ask

How do I calculate the electrical load of a house?
Add up the watts of everything you use. That is your connected load. Since it is rarely all on at once, multiply by a share such as 0.7 to get the likely running load.
What is the difference between connected load and sanctioned load?
Connected load is what your appliances add up to. Sanctioned load is what your electricity supplier has approved for your connection, and it is printed on your bill.
How many units does a 1.5 ton AC use?
At 1,500 W for 6 hours a day, about 270 units a month by simple sums. Real use is usually lower, because the compressor cycles off and star ratings differ. Your meter tells you the real figure.
Can I choose my wire size from this?
No. Wire and breaker size depend on the length of the run, how the wire is laid and local rules. A licensed electrician must decide them.

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