The Pain
I got into Red Light Therapy for recovery and quickly realized the hardware market is messy.
Manufacturers advertise numbers like “100 mW/cm² irradiance”, but that value is almost always measured at the panel surface.
Move even a few inches away and the delivered energy drops sharply due to basic geometry (Inverse Square Law).
This is high-school physics, yet most manuals never mention it.
The Fix
I didn’t want to open Excel before every workout.
So I built a physics-based dosing calculator that adjusts session time in real-time based on:
- Distance from the device
- Actual irradiance
- Target energy (J/cm²)
No guessing. Just math.
The Core Equation
Energy (J/cm²) = Irradiance (mW/cm²) × Time (seconds)
The hard part is that irradiance is not constant — it changes non-linearly with distance.
That’s the entire reason this tool exists.
Why a PWA?
I built this as a Progressive Web App for practical reasons:
Offline-first — works in gyms and basements
No app store friction — no reviews, no bloat
Fast — instant load, client-side only
Privacy-friendly — no tracking, no ads
Where I Want to Take This Next
This is still an early tool, but I’m thinking about expanding it in a few directions:
Body-zone–aware dosing
Different tissue depths (skin, muscle, joints, scalp) need different dose ranges.
Device database
A community-driven list of real-world measurements for popular panels (instead of marketing specs).
Protocol guidance
Non-medical, educational suggestions based on use case (recovery, skin, hair), not just raw numbers.
Integrated timer & planner
Sessions synced with the calculation so you don’t need a second app.
👉 Current tool: https://biohackingtested.com/red-light-therapy-calculator/
Would love feedback on:
- UX clarity
- Distance handling
- What would make this actually useful long-term
Note: This is not a medical device. Educational / personal-use tool only.
SOCIAL SHARE CARD GENERATOR