About OhmNexus

OhmNexus is a US-first platform of electrical calculators, design tools, guides, and professional engineering services, built for people who need fast, accurate answers: practicing engineers, electricians, technicians, students, and hands-on makers. Every tool is engineered for accuracy, documents the formula and standards it uses, and runs entirely in your browser with no sign-up required.

The idea behind OhmNexus

Electrical work runs on a handful of foundational relationships, beginning with Ohm's law, V = IR. The resources for applying them tend to be scattered: a formula on one site, a code table on another, a converter that never shows its working. We built OhmNexus to bring them together in one place, with the reasoning always on show, so you get a result you can check and trust rather than a number to take on faith.

The name reflects that goal. Ohm is the SI unit of electrical resistance (Ω), named after the physicist Georg Ohm, whose law is the starting point of nearly every electrical calculation. Nexus means a connection, a central link that ties things together. OhmNexus is meant to be exactly that: a hub for electrical knowledge, from simple unit conversions to design- and field-grade tools, in-depth guides, and professional engineering services, all anchored in the fundamentals of the discipline.

What you'll find here

Our calculators span battery sizing and runtime, power and unit conversions, wire and cable sizing, energy and cost, and more, with new tools added regularly. Each one shows the formula it uses and a worked example, so you can check the result and understand the method, not just copy a number.

Our guides go a step further, walking through how to approach a calculation from first principles, with the relevant calculator embedded so you can follow along.

How we keep our tools accurate

Accuracy is the whole point of a calculator, so we take it seriously:

• Documented formulas. Every calculator states the equation it applies and the assumptions behind it.
• Recognized standards. Where a result depends on conventions such as voltage, power factor, or temperature, we follow established electrical standards (NEC/NFPA 70 first, then IEC/IEEE) and label the inputs clearly.
• Worked examples. Each tool includes at least one solved example you can use to sanity-check your own numbers.
• Plain-language explanations. We explain what each result means and the limits of when it applies.

You can review the standards and references our calculations build on.

Who OhmNexus is for

Whether you are sizing a battery bank for an off-grid system, converting amps to kilowatts on site, checking a cable run, or studying for an exam, OhmNexus gives you a quick answer and the reasoning behind it.

About the author

OhmNexus is created and maintained by Saad Tahir, an electrical engineer with over a decade of design and field experience and bachelor's and master's degrees in electrical engineering. He writes and reviews every calculator and guide with that practical, on-the-job perspective, and shares his full background, areas of expertise, and editorial process on his author page.

Get in touch

Spotted an error, or want a calculator we don't have yet? We would genuinely like to hear from you. Contact us or use the feedback box at the bottom of any page.