Calculator Inputs and Outputs
Inputs
- Known illuminance (lux) — example: 1000
- Known distance (m) — example: 1
- Target distance (m) — example: 3
Results
- Estimated illuminance at target distance (lux)
- Distance ratio
- Illuminance retained
Formula used
For a point source, illuminance follows the inverse-square relation.
How to Use the Illuminance Distance Calculator
Enter the requested values, confirm the units and assumptions, then select Calculate Illuminance Distance. The default inputs provide a complete working example.
Formula
For a point source, illuminance follows the inverse-square relation.
Understanding the Results
The primary answer appears first. Supporting outputs provide related quantities, conversions, timing, costs, ratios, or intermediate values. The calculator keeps extra precision internally before display rounding.
Accuracy Tips
- Use measured values and consistent units.
- Review rates, timing, allowances, efficiency, and category-specific assumptions.
- Recalculate whenever a project condition changes.
Important Note
This calculator is an informational planning tool. Confirm critical financial, medical, construction, scientific, tax, legal, or safety decisions with an appropriately qualified professional.
Calculation Standards
This tool uses documented formulas and high-precision internal values. Displayed results may be rounded for readability. Review the assumptions and verify important decisions with a qualified professional.
Read our calculation methodology