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Both calculators run independently — change the inputs on either side to compare results.

Reynolds Number Calculator

Compute the Reynolds number Re = ρvD/μ — the dimensionless ratio of inertial to viscous forces in a flowing fluid. The single most important number for predicting laminar vs turbulent flow in pipes, channels, and around objects.

Fluid Density (kg/m³)

Flow Velocity (m/s)

Pipe Diameter (m)

Dynamic Viscosity (Pa·s)

Chemical Engineering

LMTD Heat Exchanger Calculator

Compute the log mean temperature difference (LMTD) — the effective driving force for heat transfer in a heat exchanger, given the four end-of-fluid temperatures. The standard input to the design equation Q = U·A·LMTD for sizing or rating exchangers.

Hot Fluid Inlet Temperature (°C)

Hot Fluid Outlet Temperature (°C)

Cold Fluid Inlet Temperature (°C)

Cold Fluid Outlet Temperature (°C)

Key differences

	Reynolds Number Calculator	LMTD Heat Exchanger Calculator
Category	Chemical Engineering	Chemical Engineering
Inputs required	4	4
Result	Reynolds Number	LMTD (°C)
What it does	Compute the Reynolds number Re = ρvD/μ — the dimensionless ratio of inertial to viscous forces in a flowing fluid. The single most important number for predicting laminar vs turbulent flow in pipes, channels, and around objects.	Compute the log mean temperature difference (LMTD) — the effective driving force for heat transfer in a heat exchanger, given the four end-of-fluid temperatures. The standard input to the design equation Q = U·A·LMTD for sizing or rating exchangers.