Free Online Engineering Tools
All-in-one Electronics Workbench

Numerical Calculator.

A growing collection of free, interactive calculators — Ohm's Law and RLC resonance to BMI, pregnancy and EV savings — each with live circuit diagrams and step-by-step math.

Signal Analyzer LIVE
Vpp
6.0 V
Freq
1.00 kHz
Wave
SINE
MultimeterDC V · AUTO
8.49V
True RMSRange 20V
Spectrum FFT · live
Live diagrams
On every calculator
Step-by-step
Full working shown
100% free
No sign-up, ever
Works offline
Runs in your browser
The Toolkit

Find your calculator

Search by name or browse by discipline — every tool opens instantly with live diagrams and step-by-step math.

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Why Engineers Choose It

Built to feel effortless

Real answers, real visuals, zero friction. Everything you need, nothing you don't.

Live circuit visuals

Diagrams, waveforms, and phasor plots update in real time as you type your values.

Full working shown

Every result includes the formula, substitution, and step-by-step calculation. Learn as you calculate.

Instant & offline

No loading spinners, no accounts, no ads. Runs entirely in your browser — even without internet.

Engineering standards

IPC-2152 trace sizing, E24 resistor values, datasheet LED voltages — results you can trust in real designs.

The complete Numerical Calculator suite

This calculator suite brings together a full set of free, interactive engineering tools in one focused place. From the fundamentals of Ohm's Law and DC power to advanced RLC resonance, PCB trace design, and antenna gain, every calculator delivers an instant answer with a live diagram and the formula behind it.

For everyone who works with electronics

Students use the step-by-step working to master circuit theory. Hobbyists size resistors, LEDs, and converters for real projects. Professional engineers run quick sanity checks against the same standards their work depends on. No sign-up, no paywall, no tracking — just precise tools that load instantly and work offline.

Eight categories, beautifully organized

The suite spans eight color-coded categories — DC & Resistors, Reactive Components & RLC, Power & Circuits, PCB Design, Signal & RF, Digital Logic, Health & Body, and Energy & Environment. Use the search box to jump directly to a tool, or browse by discipline. The collection keeps growing.