About CoreCalx

Free online engineering calculators built by engineers, for engineers.

CoreCalx is a free online engineering calculator platform designed for electrical, mechanical, and civil engineers. Every tool is built to deliver fast, accurate results without bloated interfaces, signup walls, or intrusive ads.

Our Mission

To make engineering calculations accessible to everyone — from students learning circuit design to seasoned professionals sizing cables on the job site.

We believe the best tools get out of your way. No accounts to create, no premium tiers to unlock, no pop-ups between you and your answer.

Why We Built CoreCalx

Before CoreCalx, the online engineering calculator landscape was frustrating. Most tools were either too slow to load, produced inaccurate results, or were so cluttered with ads and pop-ups that using them felt like navigating a minefield. Some calculators required account sign-ups just to perform a basic Ohm's Law calculation. Others displayed results without showing their methodology, making it impossible to verify the output.

We built CoreCalx because engineers deserve better. Every calculator on this site was created to solve a real problem we encountered in our own work — from sizing cables for LED video walls to decoding SMD resistor markings on a production floor. If a calculator wouldn't pass our own standards for speed, accuracy, and clarity, it doesn't ship.

Built by Engineers, Backed by Experience

Our team brings over 8 years of hands-on experience in electrical engineering, LED display systems, and power distribution. We have designed and deployed large-format LED installations, specified cable runs for industrial power systems, and developed embedded firmware for measurement devices. This isn't a hobby project — it's a professional toolkit built from real-world engineering practice.

Every calculator on CoreCalx is tested against real-world engineering standards and verified with hand calculations before publication. When you use our Cable Cross-Section Calculator, the results align with IEC 60364. When you decode a resistor with our SMD Resistor Code tool, the mapping follows IEC 60062. When you convert AWG to mm², the values correspond to ASTM B258. These aren't approximations — they are standards-grade tools.

Standards We Reference

• IEC 60364 — Low-voltage electrical installations, cable sizing and protection
• IEC 60062 — Resistor color code and SMD marking systems
• NEC (NFPA 70) — National Electrical Code for wire ampacity and conduit sizing
• ASTM B258 — Standard specification for round wire sizes (AWG)
• IEC 60063 — Preferred number series for resistors (E-series)
• SI / ASTM — Unit conversion standards for engineering calculations

Our Journey

CoreCalx started with a simple need: a fast, accurate LED resistor calculator that didn't require signing up for anything. That first tool launched in early 2024, and the response from the engineering community was immediate and encouraging. Engineers told us they wanted more — more calculators, more domains, more transparency.

From those initial 8 electrical calculators, we expanded systematically. We added cable sizing tools, voltage drop calculators, unit converters, and power calculators — each one built in response to real user requests. Today, CoreCalx offers 31 calculators spanning electrical engineering, electronics, unit conversion, and general engineering disciplines. Each addition follows the same principle: solve a real problem, verify against standards, and keep the interface clean.

Open & Free

All calculators on CoreCalx are completely free to use. No hidden fees, no account requirements, no feature gates.

CoreCalx is supported by non-intrusive advertising and will always remain free for users. Have a question or suggestion? Reach us at [email protected].