Heat Exchanger, Coil & Radiator Manufacturing worked example

Fin Density with fins counted across the gauge length of 50 fins: a worked example

This worked example runs the fin density numbers for a tougher week than the baseline: fins counted across the gauge length of 50 fins instead of the typical 100 fins. Calculate effective fin density for a finned coil or radiator core from fin count, core length, unit conversion, and a process multiplier.

The inputs for this scenario

  • Fins counted across the gauge length: 50 fins (the input this scenario stresses; the baseline uses 100)
  • Inverse of measured core length (1 / inches): 0.25 1 / in (held at the documented default)
  • Inspection or unit conversion factor: 1 x (held at the documented default)
  • Usable fin fraction after damage/missing fins: 1 x (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Effective fin density = counted fins × inverse measured core length × inspection conversion factor × usable fin multiplier.
  • Effective fin density works out to 12.5 fins / in at these inputs, and this is the headline figure for the scenario.
  • Raw fin density basis works out to 12.5 value at these inputs.
  • Usable fin multiplier works out to 1 x at these inputs.
  • Factor A x B works out to 12.5 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where fins counted across the gauge length sits at 100 fins and the headline result is 25 fins / in, this scenario comes in 50% below the baseline at 12.5 fins / in.
  • Use it at incoming or in-process inspection to verify a fin pack matches print, or to derate a core whose fins are partly crushed or missing. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Effective fin density: 12.5 fins / in (headline result)
  • Raw fin density basis: 12.5 value
  • Usable fin multiplier: 1 x
  • Factor A x B: 12.5 value

Run it with your numbers

  • To rerun this with your own numbers, open the live Fin Density calculator, set fins counted across the gauge length to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.