About eCircuitCalc
A free, suite for electronics & electrical engineering, for everyone who works with circuits.
A calculator suite, not a gadget
eCircuitCalc is a growing collection of free online calculators, unit converters and reference tools for electronics and electrical engineering. It spans 17 categories — from Ohm's Law and resistor color codes to op-amps, transformers, RF antennas and power supplies.
Our goal is simple: make accurate electrical math free, fast and approachable for everyone — from a first-year student to a field electrician. No paywalls, no scattered one-trick websites, no black boxes.
One suite, five kinds of users
Students
Follow the formula, not just the answer — every tool shows its working.
Hobbyists & Makers
Size resistors, LEDs and 555 timers before you solder anything.
Technicians
Quick, reliable numbers at the bench or in the field — on any device.
Electricians
Battery, wire, transformer and power calculations without the textbook dig.
Professional Engineers
Standards-based results you can trust, share and reference.
Everything circuit math, in one place
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Calculate component & circuit values
Resistors, capacitors, inductors, LEDs, 555 timers, filters, op-amps, transformers and more.
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Convert 250+ units
Voltage, power, frequency, AWG, dBm, temperature, metric ↔ imperial — with sensible prefixes from pico to giga.
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Browse or search the full directory
17 categories, one search box, and a tabbed overview on the homepage.
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Learn as you use
48 guided topic modules on the Learn page connect each calculator to the theory behind it.
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Request new tools
Use the contact form to request a calculator — community requests shape the roadmap.
Built the way we'd want it built
🔓 Free with no account
No premium tier, no locked answers, no sign-up. Your theme preference stays on your device; we don't collect personal data.
🧾 Step-by-step, not black-box
Each calculator will show the working behind the result, so the tool teaches as it computes.
🧱 Modular by design
Every calculator is an independent module in its own folder — new tools plug in without touching the rest.
Where we're heading
Platform & design
Interface, architecture, directory, learning hub and this page. Done
Core calculators
Ohm's Law, resistors, LEDs, RC/RL filters and the universal unit conversions go live first.
Full suite
All 17 categories live with step-by-step solutions and shareable result links.
Simulators & offline PWA
Interactive waveforms, installable offline, and community-requested tools.
Ready to start calculating?
Dive into the categories, or tell us which tool you need next.