Terms of use
Free to use
Every calculator on this site is free, with no sign-up and no limit on how often you use it.
Estimates only
The results are estimates worked out from physics and published maker data. They can only be as good as the numbers you type in. They are not a design, not an engineering calculation, and not advice about any electrical code.
Electrical work
Electricity can kill you and can start fires, and mistakes may not show until much later. By using this site you agree that:
- you won’t treat a result as approval to install anything. Your local inspector, the authority having jurisdiction (AHJ), decides what is allowed where you live, and the code edition your town has adopted may differ from the one a result assumes;
- you’ll check every result against the code edition in force where you are and against the instructions of the equipment you’re installing;
- you’ll hire a licensed electrician for work you aren’t trained and permitted to do, and get a permit where one is required.
No warranty
This site comes with no warranty of any kind. Results may contain mistakes. To the extent the law allows it, I’m not liable for any damage, injury, failed inspection, cost or loss that comes from relying on a result from this site.
Linking and sharing
You’re welcome to link to this site and to share a calculator’s result link. Please don’t copy whole pages elsewhere.
Other sites
Links to makers, standards bodies and other sites are for reference. I don’t control those sites and can’t vouch for them.
One person, not a company
This site is built and run by one person, not a business. These terms are between you and me and apply the same way to every visitor. If you want to use the site commercially or build on it, ask first through the Contact page.
Changes to these terms
These terms can change; the date at the top shows when they last did. Questions go to the Contact page.
Before you wire anything
These calculators give estimates worked out from physics and published maker data. They are not engineering, design or code advice, and they do not replace an inspection.
Electrical codes differ by edition and by town. Your local inspector, the authority having jurisdiction (AHJ), has the final say on wire size, conduit, boxes and breakers.
Mains wiring can kill and can start fires. Unless you are trained for it, hire a licensed electrician, and get a permit where your town requires one.