Calculate derated LED output at elevated operating temperatures. Uses the LED datasheet derating curve to find actual current, lumen output, and power at any case temperature — essential for hot-environment designs, enclosed fixtures, and outdoor summer conditions.
LED rated conditions (25°C)
From datasheet — absolute max case temp
Derating curve parameters
Temperature at which derating begins
% current reduction per °C above knee
Operating conditions
Lumen drop per °C above 25°C (typical 0.2-0.4%/°C)
Derated lumen output
0 lm
0mA
Derated current
0%
Lumen retained
0W
Derated power
0°C
Operating Tc
Operating within limits
Derating curve — current and lumen output vs case temperature
Output at different case temperatures
Tc (°C)CurrentLumensPower% ratedStatus
Thermal derating guidance
Rated output
Derating start / slope
Operating Tc
Current derating factor
Lumen derating factor
Derated output
Margin to Tc_max
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