About VoltLab

Electricity is one of those subjects that looks abstract right up until you try to light an LED without frying it, or figure out why a circuit with three resistors behaves nothing like one with a single resistor. The gap between the formula in a textbook and the number you actually need for the breadboard in front of you is where most beginners get stuck — and where a good calculator earns its keep.

VoltLab exists to close that gap. Instead of long articles you have to read end to end before you can do anything, the site is built around a set of small, single-purpose calculators, each aimed at one part of working with low-voltage circuits and static electricity. The Ohm’s Law Calculator solves for voltage, current, resistance, or power from any two known values. The Resistor Color Code Calculator decodes a 4-band or 5-band resistor’s color stripes into its resistance and tolerance, and works the other way too. The Series/Parallel Resistance Calculator adds up resistors wired in series or combines them in parallel to give the total resistance a circuit actually sees. The Battery Life Calculator estimates how many hours a battery will power a given current draw. The LED Series-Resistor Calculator works out the resistor value and power rating needed to drive an LED safely from a supply voltage. And the Static Charge Demo Guide estimates the capacitance and charge of a charged sphere — the physics behind a Van de Graaff generator — and walks through classic classroom static-electricity demonstrations.

Beyond the calculators, the blog and learn section cover circuit basics, resistors, batteries, and the science of static electricity, and the Museum of Electricityis a browsable collection of the pioneers, apparatus, and discoveries behind electricity — electricity pioneers, Van de Graaff generators, Leyden jars, and early batteries and lightning research — with every entry, image, and fact drawn from Wikipedia and Wikimedia Commons.

A few things worth stating plainly. VoltLab is an independent site, not affiliated with any electronics manufacturer, school, or laboratory. It is supported by advertising, which is how the tools stay free with no account required. Every result the tools produce — a current, a resistance, a battery runtime, a resistor value, an estimated charge — is an educational estimate built on the formulas and numbers you enter, not a substitute for a multimeter reading or a qualified electrician’s judgment. This site covers everyday, low-voltage electronics (batteries, LEDs, small circuits) and classroom-style static-electricity demonstrations only; it is not instruction for household mains wiring or any other high-voltage work, which should always be left to a licensed electrician. If something looks off in a tool or an article, or you think a calculator is missing that would help, the contact page is the place to say so.