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Calculator

Sunscreen SPF Outdoor Time Calculator

Fitzpatrick Skin Type

SPF Value

⚠️ Health disclaimer: This tool provides general estimates only. Actual sun protection depends on proper application, reapplication, sweating, water exposure, and individual skin sensitivity. Consult a dermatologist for personalized advice.

6 — High
13681114

Sun Protection Estimate

UV 6

Sun Protection Estimate

11h 28min

Safe Exposure Time

Reapply By

2h

Burn Time (No Sunscreen)

42min

UV Risk Level

UV 6

High

💡 Max 2 hours regardless of SPF. Reapply after swimming or heavy sweating.

Protection Timeline

ApplyReapply
02h 52min5h 44min8h 36min11h 28min

WHO Sun Protection Guide

Low (1–2): No protection needed for most people

Moderate (3–5): Seek shade during midday, wear hat & sunglasses

High (6–7): Reduce sun exposure 10am–4pm, apply SPF 30+

Very High (8–10): Extra caution — SPF 50+, protective clothing essential

Extreme (11+): Avoid outdoor exposure if possible, max protection required

Formula: Safe min = (Base min ÷ UV Index) × SPF × Application Factor · Fitzpatrick scale + WHO UV Index guidelines

Frequently Asked Questions

What does SPF actually measure?
SPF (Sun Protection Factor) measures how much UVB radiation reaches your skin compared to no sunscreen. SPF 30 lets through 1/30th (~3.3%) of UVB rays; SPF 50 lets through 1/50th (2%). The number does not scale linearly, so SPF 50 is not twice as protective as SPF 25.
How long can I stay in the sun with sunscreen?
Multiply your skin's unprotected burn time by the SPF value. If you burn in 10 minutes without protection, SPF 30 gives approximately 300 minutes of theoretical protection. In practice, reapply every 2 hours and after swimming or sweating — most people apply too little.
Does a higher SPF mean I can stay in the sun much longer?
Not proportionally. SPF 15 blocks ~93%, SPF 30 blocks ~97%, SPF 50 blocks ~98% of UVB. The difference between SPF 30 and SPF 50 is marginal. Broad-spectrum protection (both UVA and UVB), adequate quantity (2 mg/cm²), and regular reapplication matter more than chasing very high SPF numbers.