SunBeast Protection Score
Tap each body zone to show what's protecting it. Your SPS updates as you click and adapts to the UV index — the stronger the sun, the more coverage it takes to stay in the green.
Your SunBeast Protection Score
Tap a zone
11 zones · weighted by riskZone
Nothing selected yet = fully unprotected. Zones start exposed and move toward armored as you add cover.
How the score works & the science behind it
How your score is calculated
Each body zone has an importance weight — how much protecting it matters (your face counts far more than your feet). When you cover a zone, its protection blocks most of the UV; whatever isn't blocked still gets through. The score is worked out in three plain steps:
- For every zone, multiply its importance by the fraction of UV still getting through, and add these up across all zones. That's your total "weighted leak."
- Multiply that by today's UV index — the same gaps let more UV through when the sun is stronger.
- Divide by 6,000, subtract from 1, and multiply by 100. That's your SPS (never below 0).
Why 6,000? It bundles two fixed numbers into one step: the total of all the importance weights (750) and a calibration point of 8. The 8 means that being completely unprotected when the UV index is 8 — the start of the "Very High" band — scores 0. Because the sun's strength is built in, the same outfit scores lower on a fierce-sun day than a mild one, so staying in the green always takes more coverage as the UV climbs.
Zone weights & rationale
| Zone | Weight | Why it's weighted this way |
|---|
Coverage factors (share of UV blocked)
| Protection | Blocks | Basis |
|---|---|---|
| UPF 50+ / tight dark fabric | 98% | UPF 50 = 1/50 transmission; consistent, no reapplication, covers UVA+UVB. |
| UV400 / wraparound sunglasses | 99% | UV400 lenses block essentially all UV to 400 nm; wrap styles cut side entry. |
| Hat / brim / shade | 92–95% | Physical shading of upward-facing surfaces (scalp, ears, face). |
| Sunscreen SPF 30+ | 90% | Labels test ~97–98%, but typical people apply ¼–½ the tested amount (effective protection ≈ √SPF), so credited below UPF and clothing. Needs reapplication. |
| Light / translucent fabric | 80% | Thin, loose or sheer weave ≈ UPF 5–7; drops further when wet (a wet cotton tee ≈ UPF 3). |
| Sunscreen SPF 15–29 | 75% | Lower ceiling and same real-world under-application penalty. |
| Basic / fashion sunglasses (unrated) | 55% | Tint without a UV rating gives partial, inconsistent protection. |
| Bare skin | 0% | No barrier. |
Score bands
| 85–100 · Beast level | Well protected for low UV. |
| 70–84 · Shielded | Protected for low UV; add more protection if UV increases. |
| 50–69 · Patchy | At risk for moderate UV. Seek shade or add additional protection. |
| 30–49 · Exposed | Key zones exposed — add clothing, shade or sunscreen. |
| 0–29 · Scorched | Very little effective cover — high burn and damage risk. |
Selected references
- Bulliard J-L, Levi F, et al. Site distribution of different types of skin cancer. Int J Cancer, 1996 — face shows a >20-fold excess incidence per unit area for BCC/SCC.
- IARC / WHO. Solar and Ultraviolet Radiation. — nose, tops of ears and forehead receive up to ~10× the UVB of shaded sites.
- Schmalwieser AW, et al. Erythemal UV exposure during jogging. Photochem Photobiol, 2025/26 — the top of the shoulder receives ~80% of ambient UV (up to 110%).
- Sex-based differences in cutaneous SCC distribution — head/neck predominates in men, lower extremities in women.
- Osterlind A, et al. Melanoma in Denmark. — back/trunk highest in men, legs in women.
- ASTM/AATCC UPF standards; skincancer.org — UPF 15/30/50 transmit 6.7% / 3.3% / 2%.
- Real-world sunscreen application studies — typical use ≈ ¼–½ the tested thickness, effective SPF ≈ √(labelled SPF).
Built for the SunBeast toolkit.