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Thermal Cycling Life Calculator

Work out thermal cycling life instantly with clear inputs, formula shown and shareable results.

About Thermal Cycling Life Calculator

The Coffin-Manson relation makes cycles to failure inversely proportional to temperature swing raised to a power of typically 2-3 for solder. Reducing the swing from 100 to 70 degrees more than doubles life, which is why keeping a part warm is often better than cycling it cold.

Formula

Coffin-Manson

N = N_ref x (dT_ref / dT)^m, with m about 2-2.5 for eutectic solder

Worked example

With the default values below, Thermal Cycling Life Calculator returns Expected cycles to failure of 2,927. Change any input above and every figure here is recalculated in your browser.

Inputs used

Temperature swing per cycle
70 °C
Cycles per day
8 cycles/day
Rated cycles at 100 C swing
1,200 cycles
Coffin-Manson exponent
2.5

Results

Expected cycles to failure
2,927 cycles
Expected life
1.00 years
Acceleration factor versus reference
2.44 x
Damage accumulated per day
0.27331% %

Step by step

  1. 1Values used
  2. 2Coffin-Manson
  3. 3Expected cycles to failure= 2,927 cycles
  4. 4Expected life= 1.00 years
  5. 5Acceleration factor versus reference= 2.44 x
  6. 6Damage accumulated per day= 0.27331 %

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does temperature swing matter more than peak temperature?

Because fatigue is driven by the strain from mismatched thermal expansion, and strain amplitude scales with the swing, not the absolute level.

Should equipment be left powered on?

For thermal fatigue, yes — fewer cycles means less damage. But leakage-driven wear-out and energy cost push the other way, so it is a genuine trade.

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