Illuminance Converter

Supports accurate conversion between 7 illuminance units, including lux, foot-candles, and lumens, suitable for lighting engineering and optical design.

Bug report

Browser execution mode: Your data is processed in your browser and is not uploaded to the server.

Speed and Stability: Processing speed depends on your device and browser. For large batch work, the desktop version may be more stable.

Loading tool, please wait...

If the online tool fails to load or run, try the desktop tool.https://tools.yikeaigc.com/

Tool Usage

Return to old version

1Set Input Illuminance

Set the value, source unit, key target unit, and precision first; the tool converts based on lux.

Input ValueSupports 1e3

Source Unit

Key Target Unit

Number Format

Decimal Places

Thousands Separator

Copy Format

2Sample Data

3View Results

Key Result

Waiting for input

Lux reference value-

Source Unit-

Target unit-

Copy & export

1Batch input illuminance data

One entry per line; use “value unit”. If no unit is given, the default source unit on the right is used. Set the target unit first, then process.

Batch dataExample filled

Default source unit

Batch target unit

If there are more than 20 rows, only the first 20 are previewed below. Copy and export include all processed results.

2Batch results preview

Original input	Detected value	Source Unit	Target result	Lux value
Click Batch Convert

1Reference & settings

Common illuminance ranges vary by location, measurement height, fixture layout, and standard version. For projects, verify against applicable standards.

2Common illuminance reference

3Unit notes

Instructions

Software Usage Instructions

Set the input value: Enter the illuminance value to convert in the input box. Decimals and scientific notation are supported, such as 500 or 1e4.
Select the source unit: Select the unit corresponding to the current value. Available options include lux, foot-candle, lumen/square meter, lumen/square centimeter, lumen/square foot, phot, and nox.
Set the target and format: Select the primary target unit, and set the number of decimal places, number format, thousands separator, and copy format as needed.
View conversion results: Click “Start Conversion” or adjust the parameters, and the page will display the primary result, the lux reference value, and results for all units.
Batch conversion: Go to the “Batch Conversion” page and enter one item per line. Formats such as “300 lx” and “50 ft-cd” are supported. If no unit is entered, the default source unit will be used.
Copy and export: You can copy the primary result, all results, or batch results, and you can also export a CSV file for spreadsheet organization.
Save settings: Go to the “Reference & Save” page and click “Save Settings” to keep your commonly used units, precision, and copy format.

FAQ

A: 1 foot-candle is approximately equal to 10.76391 lux, and 1 lux is approximately equal to 0.092903 foot-candles. The tool uses lux as the unified reference for calculations.

A: Lumen/square meter is equivalent to lux: 1 lx = 1 lm/m². Both represent the luminous flux received per unit area.

A: Each line can contain “value unit”, such as 300 lx, 50 ft-cd, 0.08 phot, or 1200 lm/m2. If no unit is entered, the default source unit will be used.

A: phot is often used for high illuminance values, where 1 phot = 10000 lx; nox is used for low illuminance values, where 1 nox = 0.001 lx, and can be used for dim-light or photometric measurement data conversions.

A: Different units use different area bases. For example, lux is based on square meters, while foot-candles are based on square feet, so the same illuminance will be displayed as different numerical values in different units.

A: For everyday lighting estimates, you can use automatic or 2-4 decimal places; for engineering records and instrument data processing, you can choose 6 or more decimal places and make a judgment based on the precision of the original measurements.