UV index to watts per square meter (erythemal)
Type a value in UVI to get it in W/m² instantly.
That's 1.14× as strong as a European summer day, while a Mediterranean summer noon is 1.13× stronger. That is very high: avoid the midday sun.
Convert the other way: W/m² to UVI
What it means
How strong is that sun?
Information only. Burn times are for unprotected skin in full sun and vary a lot between people; sunscreen, shade and reflection from snow or water change them.
The math
How to convert UVI to W/m²
To convert UV index to watts per square meter (erythemal), multiply by 0.025.
Example: 8 UVI × 0.025 = 0.2 W/m².
In the other direction, 1 W/m² = 40 UVI.
Burn times below are for Type II: fair, usually burns. Change it above and they update.
Every unit
Your UV index in every unit
Tables
UVI to W/m² conversion table
| UVI | W/m² |
|---|---|
| 1 UVI | 0.025 W/m² |
| 2 UVI | 0.05 W/m² |
| 3 UVI | 0.075 W/m² |
| 4 UVI | 0.1 W/m² |
| 5 UVI | 0.125 W/m² |
| 6 UVI | 0.15 W/m² |
| 7 UVI | 0.175 W/m² |
| 8 UVI | 0.2 W/m² |
| 9 UVI | 0.225 W/m² |
| 10 UVI | 0.25 W/m² |
| 11 UVI | 0.275 W/m² |
| 12 UVI | 0.3 W/m² |
| 14 UVI | 0.35 W/m² |
W/m² to UVI conversion table
| W/m² | UVI |
|---|---|
| 1 W/m² | 40 UVI |
| 2 W/m² | 80 UVI |
| 3 W/m² | 120 UVI |
| 4 W/m² | 160 UVI |
| 5 W/m² | 200 UVI |
| 6 W/m² | 240 UVI |
| 7 W/m² | 280 UVI |
| 8 W/m² | 320 UVI |
| 9 W/m² | 360 UVI |
| 10 W/m² | 400 UVI |
| 11 W/m² | 440 UVI |
| 12 W/m² | 480 UVI |
| 14 W/m² | 560 UVI |
Quick answers
Quick answers
- How many W/m² is 1 UVI?
- 1 UVI is 0.025 W/m².
- How many W/m² is 10 UVI?
- 10 UVI is 0.25 W/m².
- How many W/m² is 8 UVI?
- 8 UVI is 0.2 W/m².
The units
About these units
UV index (UVI)
The WHO scale: 25 mW/m² of sunburn-weighted UV per point.
Watts per square meter (erythemal) (W/m²)
The same in SI watts.
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