About Wattwise

Wattwise builds free, single-purpose calculators for electricians, DIYers, and homeowners — sizing conductors, checking voltage drop, and estimating what a new EV charger, a heat pump, or running an appliance actually costs.

Each tool runs entirely in your browser. We don't require an account and we don't upload your inputs to a server. Where a tool relies on published standards (such as NEC conductor tables), we cite the source so you can verify it.

Who makes this

Wattwise is an independent project built and maintained by a solo developer. We focus on doing a handful of calculators really well, keeping them free, and showing the standards and assumptions behind every estimate.

How we keep it free

We show advertising and, on some pages, affiliate links to relevant products and services (such as chargers, mini-split systems, or installer quotes). These never change the result a calculator gives you.

A safety note

Our electrical calculators are estimates based on published standards — they are not a substitute for a licensed electrician or your local code authority (AHJ). Always confirm with the current code and a qualified professional before doing the work.

Contact

Questions or corrections: get in touch.