Lighting
Foot-Candles Lux Calculator
This calculator evaluates illuminance for a single lighting scenario. It uses illuminance and shows the equation behind the displayed value.
Set up the Foot-Candles Lux case
Do not mix values recorded under different conditions.
Before entering values
Keep lumens, candela, lux, and foot-candles on the correct geometric basis. If operating conditions changed between readings, calculate separate cases.
A prefix error can move the result by several orders of magnitude. For angular frequency, use Angular Frequency Calculator.
- Illuminance
- Default example: 50 fc. Enter illuminance in fc.
How the result is calculated
Here, Illuminance is obtained from lux = foot-candles × 10.7639. The formula draws on Illuminance.
The defaults produce 538.19 lx. Replace them with measurements from one operating state.
Convert illuminance from foot-candles to lux. If you also need average illuminance, continue with Lux Lumens Calculator.
Transferring the result
Archive illuminance with illuminance. Identify the instrument, rating, or assumption behind each entry.
Transfer illuminance with all available digits during downstream arithmetic. Keep a separate displayed value if reporting precision differs.
How to use the result
The primary answer, Illuminance, describes only the entered scenario. Compare it with illuminance, uniformity, driver loading, voltage loss, energy use, and maintained output.
Label alternate cases rather than overwriting the baseline.
Common entry mistakes
Unit-prefix mistakes often dominate the arithmetic error.
Check the input source before adding a safety or correction factor.
Practical limits
The conversion changes units only; it does not account for meter calibration or spatial uniformity.
Additional checks may be needed for driver efficiency, optical loss, surface reflectance, and beam-edge definition. Resolve material omissions before selecting a standard size or rating.
Use photometric data for the actual fixture, optic, mounting height, and task plane.
Before carrying the answer forward
Begin by confirming illuminance at the operating point represented by the other entries. Record whether it came from a meter, nameplate, data sheet, or design assumption.
Use illuminance alongside illuminance, uniformity, driver loading, voltage loss, energy use, and maintained output. Preserve the unrounded number until all dependent calculations and comparisons are complete.
Document any effect handled outside this page, especially fixture distribution, reflections, mounting, maintenance, and meter position. That note prevents a later reader from assuming the simple equation covered it.
Before relying on the answer
Why does the field result disagree with this page?
Recheck units and operating state before investigating driver efficiency, optical loss, surface reflectance, and beam-edge definition.
Can I change several inputs at once?
Change one uncertain entry at a time and preserve the baseline. Use photometric data for the actual fixture, optic, mounting height, and task plane.
Does the answer include a design margin?
No. Compare the value with the fixture photometric file and the measured task plane and apply relevant equipment and installation requirements.