About Luminosit
Buying a light bulb quietly turned into a numbers problem. The box that used to promise a familiar wattage now leads with lumens; a desk or a kitchen is supposed to hit some illuminance figure nobody ever taught you; “warm white” and “daylight” turn out to be points on a Kelvin scale; a torch is rated in candela rather than a brightness you can picture; and whether an LED pays for itself depends on its wattage, how many hours it runs, and what you pay per kilowatt-hour. None of it is complicated once someone explains it — but the explanations are scattered, and the shops selling the bulbs aren’t the most neutral place to learn.
Luminosit exists to take that arithmetic off your plate. Rather than one long guide you have to read end to end, the site is built around a set of small, single-purpose calculators, each aimed at one question about light. The Lumens ↔ Lux Calculator converts between the total light a source puts out and the illuminance that actually lands on a surface of a given area. The Watts to Lumens Calculator estimates brightness from wattage across bulb types, so an old incandescent and a modern LED can be compared on equal terms. The Room Lighting Requirement Calculator works out roughly how many lumens a room needs from its size and how it’s used. The Candela ↔ Lumens Calculator moves between luminous intensity and total output using a beam angle, which is where spotlight and torch specs start to make sense. The Lux at Distance Calculator shows how quickly illuminance falls off as you move away from a source, following the inverse-square law. And the LED Energy Savings Calculator turns wattage, running hours, and your electricity price into the running cost of a bulb and what switching to LED would save.
Beyond the calculators, the blog and learn section cover light science, photometry and units, lamps and bulbs, and lighting design, along with the reasoning behind the numbers the tools produce. The Museum of Light is a browsable collection of lamps and luminaires, the instruments used to measure light, and the physics behind how it is made and seen, with every entry, image, and fact drawn from Wikipedia and Wikimedia Commons.
A few things worth stating plainly. Luminosit is an independent site — not an electrician, a lighting designer, or a manufacturer, and not affiliated with any bulb, fixture, or lighting brand. It is supported by advertising, which is how the tools stay free with no account required. Every figure the tools produce — a lux level, a lumen estimate, a candela conversion, a room target, an energy saving — is an educational estimate built on the numbers you enter and standard photometric formulas, not professional electrical, safety, or engineering advice. For anything involving mains wiring, a fixed installation, or a workplace lighting standard, consult a qualified electrician or lighting engineer. If a tool looks off, or there’s a calculator you wish existed, the contact page is the place to say so.