Softbox Coverage Calculator

Calculate the illuminated coverage area, soft light spread angle, and subject-to-source distance for softboxes. Find the ideal softbox size for your subject and shooting distance.

Softbox Dimensions

Width 24 in

Height 36 in

Shape

Setup

Distance to Subject 5 ft

Light Power 500 Ws

Modifier

Subject Size 24 in (reference)

Coverage Analysis

Softbox face area—

Coverage at subject distance—

Subject-to-source ratio—

Softness quality—

Effective lux at subject—

Approx. f-stop @ ISO 100—

Subject coverage—

Recommended for—

—

in² face

Softbox area

—

quality

Light softness

—

× subject

Size ratio

—

lux approx

At subject

The calculators and tools on LightingCalc.lighting are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. LightingCalc.lighting makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.