Lumens measure how much light a torch or weapon light puts out in total; candela measures how intense the centre of the beam is, and candela is what decides how far the light reaches. Under the ANSI/PLATO FL1 standard, beam distance in metres works out as 2 × √candela, so a 20,000 cd light throws about 283 m and an 80,000 cd light about 566 m, whatever their lumen figures.
That is why two lights with the same 1,000 lumens can behave completely differently: one floods a barn with light, the other puts a tight hotspot on a gatepost across a field. The chart below does the arithmetic for you, and the second table puts real, manufacturer-published figures against lights we stock.
Key takeaways
- Lumens are total output (flood); candela is peak beam intensity (throw).
- ANSI/PLATO FL1 beam distance is where the beam falls to 0.25 lux, which works out as 2 × √candela in metres.
- Quadrupling candela only doubles the throw: 20,000 cd gives about 283 m, 80,000 cd about 566 m.
- Many multi-fuel lights publish higher lumens and candela on their rechargeable cell than on CR123A, so check which battery a figure refers to.
- ANSI beam distance is where the light becomes very dim, not where you can identify a target; real identification range is much shorter.
What lumens and candela actually measure
Lumens are the total amount of visible light leaving the head, in every direction the reflector or optic sends it. A high-lumen light lights up a lot of area at once: walls, hedges, the ground at your feet.
Candela is the luminous intensity in the brightest part of the beam, normally the centre of the hotspot. Streamlight's summary of the ANSI/PLATO FL1 standard defines peak beam intensity as "the maximum luminous intensity typically along the central axis of a cone of light" (Streamlight ANSI FL1 summary). Squeeze the same lumens into a tighter cone with a deeper reflector or a lens, and candela rises sharply.
Neither number is better on its own. For work inside 25 m, spill matters more than throw. For anything across open ground, candela sets the limit.
Candela to throw distance chart
The FL1 standard defines beam distance as the distance at which the beam has fallen to 0.25 lux, roughly the light of a full moon. Illuminance falls with the square of distance, so distance = √(candela ÷ 0.25) = 2 × √candela. Every figure below was recalculated from that formula and rounded to the nearest metre, with yards alongside.
| Peak beam intensity | ANSI beam distance | In yards | Typical use |
|---|---|---|---|
| 2,500 cd | 100 m | 109 yd | EDC torch, close work |
| 5,000 cd | 141 m | 155 yd | Compact light, indoor and yard work |
| 10,000 cd | 200 m | 219 yd | Compact to full-size weapon light, general use |
| 20,000 cd | 283 m | 309 yd | Balanced rifle or shotgun light |
| 40,000 cd | 400 m | 437 yd | High-candela rifle light |
| 65,000 cd | 510 m | 558 yd | Turbo or "HP" thrower |
| 80,000 cd | 566 m | 619 yd | Long-reach rifle light |
| 100,000 cd | 632 m | 692 yd | Maximum-throw turbo head |
Read the table the other way round and the square-root relationship is obvious: to double the reach you need four times the candela. Going from 20,000 cd to 40,000 cd adds about 117 m; going from 80,000 cd to 100,000 cd adds only about 66 m.
Real examples from the range
These are the manufacturers' own published figures on the high setting. Where a light runs on two battery types, the table gives both, because the difference is often large.
| Light | Battery | Lumens | Candela | Beam distance |
|---|---|---|---|---|
| Streamlight TLR-7 X | CR123A / SL-B9 | 550 / 725 | 7,200 / 9,500 | 170 m / 195 m |
| SureFire X300U-A | 2 × CR123A | 1,000 | 11,300 | 213 m |
| Streamlight TLR-1 HL | 2 × CR123A | 1,000 | 20,000 | 283 m |
| Streamlight ProTac 2.0 Rail Mount | SL-B50 | 2,000 | 17,700 | 266 m |
| Streamlight ProTac 2.0 Rail Mount HP | SL-B50 | 2,000 | 85,000 | 583 m |
| Streamlight TLR-1 HP-X | 2 × CR123A / SL-B9 | 1,000 / 1,300 | 53,000 / 77,000 | 460 m / 555 m |
| SureFire M340DFT | CR123A / SF18350 | 350 / 650 | 55,000 / 95,000 | 469 m / 616 m |
| SureFire M640DFT | 2 × CR123A / SF18650 | 600 / 700 | 90,000 / 100,000 | 600 m / 632 m |
| Holosun RAID | 18650 | 900 | 100,000 | 632 m (calculated) |
Two comparisons in that table are worth pausing on. The ProTac 2.0 Rail Mount and the Rail Mount HP both publish 2,000 lumens, yet one has 17,700 cd and the other 85,000 cd: same output, very different reach. And the SureFire M340DFT makes only 650 lumens but out-throws the 2,000-lumen ProTac 2.0 HP, because SureFire has put the effort into the optic rather than the lumen figure. The Holosun RAID makes the same point: Holosun now publishes it at 900 lumens and 100,000 cd (Holosun RAID).
Which should you prioritise?
Close work: barns, yards, woods, indoors
Inside about 25 m (27 yd), a broad beam with plenty of spill is more useful than a pencil of light. It shows you the whole scene, and a very tight hotspot bounced off a nearby white wall can dazzle you. Something in the 10,000 to 20,000 cd band, like the TLR-1 HL or X300U-A, is about right.
Open ground and distance
Across fields, foreshore or a long ride, candela is everything. The 50,000 cd and up "HP", "HC" and "Turbo" models are built for this. Mist, rain and airborne dust scatter light back at you, and a tight beam copes with that better than a wide one because less of the light hits the particles close to the muzzle. For night vermin work specifically, our guide to optics for fox and night vermin control covers lamping and the rules around it.
Both
A balanced 20,000 to 40,000 cd light is the sensible single answer for a general-purpose long gun. If you're comparing specific models, the best weapon lights guide and the Streamlight TLR comparison put these numbers against real models. For torches rather than weapon lights, see our handheld torch buying guide.
Expert tip
ANSI beam distance is the point where the beam fades to 0.25 lux, which is about moonlight. You will see that something is there well before that point, but you won't be able to say what it is. When you're comparing lights, use the beam distance to rank them, and expect your real identification range to be a good deal shorter than the printed figure.
Check which battery the numbers refer to
Multi-fuel and dual-fuel lights often reach their headline figures only on the rechargeable cell. Streamlight lists the TLR-7 X at 725 lumens on its SL-B9 pack but 550 lumens on a CR123A (Streamlight TLR-7 X). SureFire lists the M340DFT at 95,000 cd on its SF18350 cell and 55,000 cd on a CR123A (SureFire M340DFT). If you plan to run primaries, use the CR123A column. The trade-offs are explained in rechargeable vs CR123.
Frequently asked questions
Are more lumens always better?
No. More lumens with the same beam shape just adds spill, and in a confined space that spill can reflect back into your eyes. For reach, candela matters far more than lumens.
What is a good candela figure for a rifle light?
Around 20,000 to 40,000 cd suits a general-purpose rifle or shotgun used at mixed distances. For identifying targets across open ground, look at the 50,000 cd and up high-candela models.
How is throw distance calculated?
ANSI/PLATO FL1 beam distance is the distance at which the beam falls to 0.25 lux. Because light falls off with the square of distance, that works out as 2 × √candela in metres.
Why does the same light have two sets of figures?
Multi-fuel lights can run on a rechargeable lithium-ion cell or on CR123A primaries, and the rechargeable cell can usually supply more current. Manufacturers publish both, so compare like with like.
Shop this guide
- Weapon lights: every rail, pistol-rail and forend light we list, with lumens and candela in the titles.
- Streamlight TLR weapon lights: the widest spread of flood-to-throw options.
- SureFire weapon lights: the Turbo Scout Lights for maximum candela.
- Handheld torches: the same flood-versus-throw trade-offs in a torch you carry.
