Lux to Foot Candles Converter that turns a light meter reading into foot-candles or lux, checks it against IES levels for 17 rooms and tasks, and then finds its lumens and candela.
Type a light meter reading, pick its unit and the unit to convert it to.
Room, Area & Distance
Common Conversions
| Lux | Foot-candles |
|---|---|
| 1 lx | 0.092903 fc |
| 10 lx | 0.92903 fc |
| 10.7639 lx | 1 fc |
| 50 lx | 4.64515 fc |
| 53.8196 lx | 5 fc |
| 100 lx | 9.2903 fc |
| 107.639 lx | 10 fc |
| 200 lx | 18.5806 fc |
| 215.278 lx | 20 fc |
| 300 lx | 27.8709 fc |
| 322.917 lx | 30 fc |
| 400 lx | 37.1612 fc |
| 500 lx | 46.4515 fc |
| 538.196 lx | 50 fc |
| 1,000 lx | 92.903 fc |
| 1,076.39 lx | 100 fc |
| 2,152.78 lx | 200 fc |
| 4,000 lx | 371.612 fc |
| 10,000 lx | 929.03 fc |
| 10,763.9 lx | 1,000 fc |
| 100,000 lx | 9,290.3 fc |
IES Levels by Room
| Room or task | IES (fc) | IES (lx) | Your level |
|---|---|---|---|
| Living Room or Bedroom | 10–20 fc | 107.6–215.3 lx | Above |
| Kitchen, General | 30–40 fc | 322.9–430.6 lx | Above |
| Kitchen Task (Stove, Sink) | 50–100 fc | 538.2–1,076 lx | Below |
| Dining Room | 30–40 fc | 322.9–430.6 lx | Above |
| Bathroom | 20–50 fc | 215.3–538.2 lx | Within |
| Home Office or Reading | 20–50 fc | 215.3–538.2 lx | Within |
| Hallway or Entry | 5–20 fc | 53.82–215.3 lx | Above |
| Garage, General | 30 fc | 322.9 lx | Above |
| Garage Workbench or Shop | 100 fc | 1,076 lx | Below |
| General Office | 30–50 fc | 322.9–538.2 lx | Within |
| Conference Room | 15–60 fc | 161.5–645.8 lx | Within |
| Classroom | 30–50 fc | 322.9–538.2 lx | Within |
| Retail Sales Floor | 25–100 fc | 269.1–1,076 lx | Within |
| Storage, Bulky Items | 5–20 fc | 53.82–215.3 lx | Above |
| Corridor or Stairway | 2.5–10 fc | 26.91–107.6 lx | Above |
| Lunch or Break Room | 5–20 fc | 53.82–215.3 lx | Above |
| Fine Assembly or Inspection | 50–200 fc | 538.2–2,153 lx | Below |
Step-by-Step Math
- 1 fc = 1 lm/ft² and 1 lx = 1 lm/m², and 1 ft² = 0.09290304 m², so 1 fc = 1 ÷ 0.09290304 = 10.7639104 lx
- Result = 500 lx ÷ 10.7639 = 46.4515 fc
Lux to Foot Candles Converter Formula
A foot-candle is one lumen per square foot, and a lux is one lumen per square meter. Both describe light landing on a surface, so the only difference between them is the size of the area the lumens are spread over.
One square foot is exactly 0.09290304 m², so one foot-candle packs the same lumen into an area about 10.76 times smaller. The NIST Guide to the SI lists the factor as 1 fc = 10.76391 lx, and the Lux to Foot Candles Converter carries it to full precision.
$$E_{fc} = \frac{E_{lx}}{10.7639}$$
$$E_{lx} = E_{fc} \times 10.7639$$
To convert lux to foot candles, divide the lux reading by 10.7639. A 100 lux reading is 9.29 fc and a 500 lux reading is 46.45 fc. To go the other way, multiply, so 200 foot candles equals 2,152.8 lux and 20 foot candles equals 215.3 lux.
The same converter also handles kilolux (1,000 lx), millilux (0.001 lx) and phot (10,000 lx). Pick any of them in the reading’s unit or in Convert To, and the step list shows the path through lux. A sixth input unit, Lumens over Lit Area, turns a lumen count into lux or foot-candles.
Lux to Foot Candles Chart
The chart covers the readings people convert most, including 100, 300, 500, 1,000 and 4,000 lux. Values are rounded to four decimals, while the Lux to Foot Candles Converter shows six significant figures for any number you type.
| Lux (lx) | Foot-candles (fc) | Lux (lx) | Foot-candles (fc) |
|---|---|---|---|
| 1 | 0.0929 | 400 | 37.1612 |
| 10 | 0.9290 | 500 | 46.4515 |
| 20 | 1.8581 | 1,000 | 92.9030 |
| 50 | 4.6452 | 4,000 | 371.6122 |
| 60 | 5.5742 | 5,000 | 464.5152 |
| 100 | 9.2903 | 10,000 | 929.0304 |
| 200 | 18.5806 | 100,000 | 9,290.3040 |
| 300 | 27.8709 | — | — |
Foot-candle targets in US lighting guides are usually round numbers, so the reverse chart is just as useful. It answers questions like how many lux is 1 foot-candle, or what 30 foot candles is in lux.
| Foot-candles (fc) | Lux (lx) | Foot-candles (fc) | Lux (lx) |
|---|---|---|---|
| 1 | 10.76 | 40 | 430.56 |
| 5 | 53.82 | 50 | 538.20 |
| 10 | 107.64 | 100 | 1,076.39 |
| 20 | 215.28 | 200 | 2,152.78 |
| 30 | 322.92 | 1,000 | 10,763.91 |
Lux vs Foot Candle
Lux is the SI unit and is used on most light meters, data sheets and standards outside the US. The foot-candle is the US customary unit, and it is still the unit in IES recommendations, US building specs and many American light meters.
The foot-candle takes its name from a simple picture. A source of one candela lights a surface one foot away at one lumen per square foot, which is 1 fc. Move that surface to one meter away and the same source gives 1 lux, the smaller unit.
A few rarer units show up in older papers and photometry tools. The phot is one lumen per square centimeter, or 10,000 lux, and the nox is an old name for one millilux, which is why the dropdown reads Millilux (mlx, nox). Kilolux keeps large readings short, so 25,000 lux reads as 25 klx, and the Lux to Foot Candles Converter reads and returns all five illuminance units.
Lux, Foot Candles and Lumens
Lux and foot-candles measure light arriving at a surface, while lumens measure the total light a source puts out. That is why 5,000 lux is not the same as 5,000 lumens, and why converting between them always needs an area.
$$\Phi = E \times A$$
Use lux with square meters, or foot-candles with square feet, and the result comes out in lumens. The second card of the Lux to Foot Candles Converter does this for the Lit Area you enter, and it also shows how much floor 1,000 lumens would cover at your reading.
So 50 foot candles is 50 lumens on every square foot, or 5,000 lumens over a 100 sq ft room. 100 foot candles in lumens is 100 lm per square foot, and 200 lux in lumens is 200 lm per square meter, or 2,000 lm over 10 m². In the same way, 60 lux over 10 m² takes 600 lumens.
Going from lumens to foot candles is the reverse, and it is a unit choice in the converter. Pick Lumens over Lit Area (lm) as the reading’s unit, and Lit Area moves into Quick Setup as a required field.
$$E = \frac{\Phi}{A}$$
1,000 lumens spread evenly on 1 m² gives 1,000 lux, while the same 1,000 lumens over a 100 sq ft room gives 10 fc, or 107.6 lux. 5,000 lumens on 20 m² gives 250 lux, which the converter can also show as 0.25 klx.
In this mode, card 2 switches to the level in the other unit and the lumens needed to reach the room target you picked. A 100 sq ft general office at its 40 fc IES average needs 4,000 lm landing on the floor, while 1,000 lm at 10 fc covers 100 sq ft and at 50 fc covers only 20 sq ft.
These figures assume every lumen lands on the surface. Real rooms lose part of the light to fixtures, walls and dirt, and the Lumen Calculator adds those losses when you size bulbs for a room.
What Is a Normal Lux Level?
A normal lux level depends on the task. The first card of the Lux to Foot Candles Converter compares your reading with the IES value for the room you pick, and the IES Levels by Room table marks your level as below, within or above each room’s range.
Home values follow the IES residential levels in Penn State’s EGEE 102 lighting table. Commercial values are IES 10th Edition averages from Orion Lighting’s IES guideline brochure, measured on a horizontal plane at desk height.
| Room or task | IES level (fc) | IES level (lux) | Target used by the converter |
|---|---|---|---|
| Living room or bedroom | 10–20 | 108–215 | 15 fc (midpoint) |
| Kitchen, general | 30–40 | 323–431 | 35 fc (midpoint) |
| Kitchen task (stove, sink) | 50–100 | 538–1,076 | 75 fc (midpoint) |
| Bathroom | 20–50 | 215–538 | 35 fc (midpoint) |
| Home office or reading | 20–50 | 215–538 | 35 fc (midpoint) |
| Hallway or entry | 5–20 | 54–215 | 12.5 fc (midpoint) |
| Garage workbench or shop | 100 | 1,076 | 100 fc |
| General office | 30–50 | 323–538 | 40 fc (IES average) |
| Classroom | 30–50 | 323–538 | 40 fc (IES average) |
| Retail sales floor | 25–100 | 269–1,076 | 50 fc (IES average) |
| Corridor or stairway | 2.5–10 | 27–108 | 5 fc (IES average) |
| Fine assembly or inspection | 50–200 | 538–2,153 | 100 fc (IES average) |
So 300 lux, or 27.9 fc, is just under the 30 fc low end for an office, classroom or kitchen, but inside the 20–50 fc range for a bathroom or home office. 10 foot candles of light is a dim living room or bedroom level, 20 foot candles sits at the top of that range, and 30 foot candles is the level for general garage use.
How Bright Are Common Lux Readings?
Low readings are easier to judge against a known reference. The ANSI/PLATO FL1 flashlight standard uses 0.25 lux as its beam-distance limit, which Pelican describes as about a full moon on a clear night.
| Reading | Foot-candles | How it compares |
|---|---|---|
| 1 lux | 0.093 | 4 times the 0.25 lux full-moon level |
| 10 lux | 0.93 | Under the 2.5 fc corridor minimum |
| 20 lux | 1.86 | Still under the corridor minimum |
| 100 lux | 9.29 | Just below a living room |
| 300 lux | 27.87 | Inside the bathroom and home office range |
| 1,000 lux | 92.90 | Near the 100 fc workbench level |
| 10,000 lux | 929.03 | Light therapy box level |
A 1,000 lux reading is not dark at all, since it is bright enough for close bench work indoors. 10,000 lux is the exposure Mayo Clinic gives for a seasonal affective disorder light box, used 16 to 24 inches from the face. 1,000 foot candles is 10,764 lux, just above that level.
A night light has no single lux value, since the reading depends on its output and how far away you measure. A meter reading at the bed is the only reliable figure, and for scale, the lowest IES corridor level is 2.5 fc, about 27 lux.
Lux to Candlepower
Candlepower is the older name for luminous intensity, which is now measured in candela. A lux reading taken straight in front of a small light at a known distance gives its candela through the inverse square law, and card 3 of the Lux to Foot Candles Converter does this from the Distance to Light field.
$$I = E_{lx} \times d^2$$
With d in meters, the result is in candela. A 500 lux reading at 8 ft (2.44 m) means about 2,973 cd, and that light would read a quarter as much at twice the distance. The card also gives the ANSI throw, the distance where the light falls to 0.25 lux, which is 357.8 ft for this example.
A 300 candlepower light gives 300 lux at 1 m, or 3 fc at 10 ft, and its ANSI throw is about 34.6 m (114 ft). Is 1 lumen equal to 1 candle? No. A one-candela source shining equally in every direction gives out 4π, or about 12.57 lumens.
Lumens alone cannot give candlepower, because the beam angle decides how tightly the light is packed. 10,000 lumens spread in every direction is about 796 cd, but the same 10,000 lumens in a 20° beam is about 104,800 cd. The beam mode of the Lumen Calculator converts between lumens, candela and throw for any beam angle.
Is 1 Lux Equal to 1 Watt?
No. Lux counts light weighted by how sensitive the eye is, while watts count raw power. The BIPM candela definition fixes 683 lumens per watt at 540 THz, a green near 555 nm where the eye is most sensitive.
That sets a floor, not a fixed rate. One lux of that green light carries about 1.46 mW per square meter, so card 4 of the Lux to Foot Candles Converter shows 0.732 W/m² as the least power that can give a 500 lux reading. White light needs more power per lux, since part of its spectrum falls where the eye responds less, as the Blackbody Radiation Calculator shows for any color temperature.
Can a Phone Measure Lux?
A phone can give a rough lux reading through its ambient light sensor, but it is not a calibrated meter. A Toronto Metropolitan University study tested 21 phones with free lux apps against a digital lux meter and found readings that varied widely, even between phones of the same model.
The authors concluded that phone apps are not reliable for workplace lighting checks. Use a lux meter for anything that matters, hold it flat at desk height for task lighting, and enter its reading in the Lux to Foot Candles Converter to compare it with the IES level for the room.
For other light and lens math, the Optics Calculators hub includes tools such as the Laser Brightness Calculator and the Diopter Calculator, all built on the same sourced formulas.