basic

LMTD Log Mean Temperature Difference Calculator

LMTD = (ΔT1−ΔT2)/ln(ΔT1/ΔT2) — heat exchanger driving force.

Calculates the Log Mean Temperature Difference (LMTD) for counterflow or parallel-flow heat exchangers from terminal temperatures.

Daniel Oh By Daniel Oh
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

LMTD = (ΔT1 − ΔT2) / ln(ΔT1/ΔT2); Q = UA × LMTD

In depth

Calculates the Log Mean Temperature Difference (LMTD) for counterflow or parallel-flow heat exchangers from terminal temperatures.