Red Light Dose Calculator
Red light therapy is a dosing problem wearing a wellness costume. The math is mW/cm² × seconds ÷ 1,000 = J/cm² — and the difference between a dialed session and a wasted one is just that arithmetic.
Use the manufacturer's measured value at your actual sitting distance — not the at-surface headline spec.
Not medical advice. Eyes closed or goggles near high-output panels; skip photosensitizing medications territory without a doctor's OK.
Why panel power changes everything
Two panels can both say "red light therapy" while one delivers 3× the irradiance at your sitting distance. The weaker panel isn't useless — it just needs three times the session length for the same J/cm². That's the real trade hiding behind the price gap, and it's why our panel rankings sort by measured power per dollar, not marketing claims.
Frequently asked questions
How is red light therapy dose calculated?
Dose in joules per square centimeter equals irradiance (mW/cm²) × time (seconds) ÷ 1,000. A panel delivering 50 mW/cm² at your distance for 10 minutes (600 s) delivers 30 J/cm².
What is a good red light therapy dose?
Common evidence-based windows: roughly 3–15 J/cm² for skin and facial goals, 10–30 J/cm² for wound healing and superficial tissue, and 20–60 J/cm² for muscle and joint recovery where light must penetrate deeper. Photobiomodulation is biphasic — past the ceiling, more light reduces the effect.
Does distance from the panel matter?
Enormously. Irradiance falls off quickly with distance — a panel rated 100 mW/cm² at 6 inches may deliver a third of that at 18 inches. Use the manufacturer's measured irradiance at YOUR sitting distance, not the headline number.
Can you overdose red light therapy?
You will not injure yourself like a sunburn, but the dose-response curve is biphasic: beyond the effective window, additional light progressively cancels the benefit. Longer is not better — dialed is better.