L70 Lifetime Calculator

TM-21 lumen maintenance projection from LM-80 test data — predicts L70, L80, and L90 lifetimes

Test Conditions

LM-80 Test Temperature

Drive Current (mA)

Initial Lumens (at t=0)

In-Situ Temperature (degrees C)

Actual LED junction temp in your fixture

Reporting Multiplier (TM-21)

LM-80 Lumen Maintenance Data Points

Enter measured lumen maintenance (%) at each test interval. Minimum 3 points required.

Load preset:

Hours (h)

Lumen Maint. (%)

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L90 Lifetime (h)

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L80 Lifetime (h)

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L70 Lifetime (h)

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L50 Lifetime (h)

Lumen Maintenance Projection

TM-21 Fit Parameters

Notes

The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.