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Free Electrical Calculators
Free tools for planning electrical work at home. Each one gives an estimate and explains the math. An expert electrician confirms the details for your home.
Pick a calculator
Panel Load Calculator
Estimate your home's electrical load in amps and see if 100, 150 or 200 amp service fits, or if your panel can take a new appliance.
Open the calculator → Panel Upgrade Cost Calculator
Price range for a same-size panel replacement or a 100 A to 200 A service upgrade.
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EV Charger Cost Calculator
Breaker size, wire size, panel check and install cost range for a Level 2 home charger.
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Wire Size Calculator
Find the wire gauge for your amps, run length and voltage drop target.
Open the calculator → Voltage Drop Calculator
See how many volts a wire loses over its length, in volts and percent.
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Smoke and CO Detector Calculator
How many smoke and carbon monoxide alarms your home needs, and where they go.
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Recessed Lighting Calculator
How many recessed lights a room needs, how far apart, and how far from the walls.
Open the calculator → Rewiring Cost Calculator
Estimate the cost to rewire a whole house or one floor, from the home's size.
Open the calculator →Calculator questions
How the free tools work and who made them.
Are these electrical calculators free?
Yes. They are free to use, with no sign-up.
Are the results exact?
No. Each tool gives an estimate for planning and shows the math and the sources behind it. An expert electrician confirms the details for your home.
Who made these calculators?
Electric Sandro, an electrical business based in Quantico, Virginia. Each tool lists its sources, such as the National Electrical Code and U.S. Department of Energy pages, and the date it was last updated.
Do I need a permit for the work the calculator is about?
Often, yes. New circuits, EV chargers and panel changes need a permit in Virginia. Check our Northern Virginia permit checker for your town.
Need an electrician you can trust?
Tell us about the job. We call you back, explain the work in plain words and set a time.