A flashlight lumens reference, anchored to real lights

Lumen figures are hard to picture because there is nothing to compare them to. A box says 1,000 lumens and the number means nothing until you have held one. This page fixes each level to a real light whose manufacturer publishes the figure, so the scale is anchored to something checkable rather than to adjectives.

It also does the thing most lumen charts leave out. Two lights with identical output can differ by a factor of four in how far they see, and the reference is misleading without that column. Every row below carries the published reach beside the published output.

What a lumen actually measures

A lumen is a unit of total luminous flux — the entire quantity of visible light a source emits, added up in every direction it goes. Under ANSI/PLATO FL 1 the figure is measured in an integrating sphere 30 seconds after switch-on, which is why it is sometimes called out-the-front output.

The critical property is that it says nothing about where the light goes. Pour a fixed quantity of light into a narrow column and you get a beam that reaches a kilometer. Spread the same quantity across a wide field and you get something that lights a room and dies at 200 meters. The lumen figure is identical in both cases. Lumens vs candela covers the distinction in full.

The reference, from 30 lumens to 4,000

Turning reach into intensity

Beam distance and candela are two ways of saying the same thing, and the conversion between them is exact rather than approximate. That is unusually convenient: it means you can derive an intensity figure for any light that publishes a distance, and compare lights whose makers publish different halves of the picture.

Divide candela by lumens and you get a single number describing how concentrated a beam is. Nobody publishes it, and it explains more than any specification that is published.

The range runs from 3 to 256, which is a factor of 85 within a set of ordinary lights. A number under about 10 is a flood for close work. Anything over about 50 is built to reach. The middle of the range is where general-purpose lights sit, and the ProTac HL-X at 27 is close to the ideal compromise if you want one light for everything.

Why the brightest light on the page reaches the least far

The Nitecore P20iX publishes 4,000 lumens — more than any other light here — and 221 meters, less than any other light here except the two keychain-class entries. That is not a fault and it is not a contradiction. It is a design decision made visible.

A reflector concentrating light into a tight column produces high candela and long reach at the cost of everything outside the column. A shallow reflector or a diffused emitter spreads the same lumens across a wide field. The P20iX is built to fill a space — a yard, a warehouse aisle, the inside of a vehicle — and it does that better than anything else on the page. Ask it to identify something at 300 meters and it will lose to a light with 40 percent of its output. Throw vs flood sets out the engineering trade.

How to use this reference

• Find the job, then the number. Lighting a room or a work area is a lumen question. Identifying something at distance is a candela question, and the lumen figure will mislead you.
• Check whether the maker publishes a distance. If they publish output and nothing else, you cannot tell what shape the beam is — and on this site that counts against a light.
• Do the arithmetic yourself. Distance squared, times 0.25, gives candela. Divide by lumens for the concentration figure. Two multiplications tell you more than the marketing copy.
• More is not better past a point. Above roughly 1,000 lumens at arm's length, extra output is glare bouncing back at you. See how many lumens do I need for the job-by-job version of this.

What this page does not do

It does not convert flashlight lumens into household bulb wattages. That comparison gets asked constantly and it is a category error: a bulb radiates in every direction to light a room, and a flashlight concentrates output into a beam. A 60-watt incandescent bulb and a 500-lumen flashlight are not doing the same job even where the flux figures are similar, and the flashlight will look far brighter pointed at a wall while lighting the room far worse.

It also does not estimate anything. Every figure above is published by the manufacturer of the light named in the row, with the source linked. Where a maker does not publish a beam distance — the Petzl e+LITE here — the cell says so rather than carrying a number we inferred.