Heat Exchanger Sizing Calculator
Estimate heat duty, logarithmic mean temperature difference and preliminary heat-transfer area for single-phase liquid applications.
Preliminary calculation scope
This calculator is intended for preliminary liquid-to-liquid thermal sizing. It does not determine the final exchanger model, plate quantity, tube configuration, pressure drop or mechanical dimensions.
For steam, refrigerants, gases, condensing, evaporating, slurry, crystallizing or high-viscosity duties, please request engineer-assisted selection.
Hot side
Physical properties (auto)
Process data (optional)
Cold side
Physical properties (auto)
Process data (optional)
Design conditions
Fouling adjustment is applied as a preliminary empirical multiplier on U. The design margin is applied separately to the calculated area.
Enter hot- and cold-side operating conditions, then press Calculate. The tool will estimate heat duty, LMTD and a preliminary heat-transfer area range.
Sizing of a heat exchanger — what this tool does
Sizing of a heat exchanger starts with an energy balance: the heat duty is derived from flow rate, specific heat and the temperature change on each side. The logarithmic mean temperature difference (LMTD) then describes the driving force between the two streams, and a preliminary heat-transfer area follows from the duty, the LMTD and an assumed overall heat-transfer coefficient for the construction and fluids selected. This calculator performs exactly that sequence for single-phase liquid duties and applies a fouling adjustment and a design margin to the result.
What it does not do
The output is a preliminary estimate for early planning and budget discussions, not a final selection. It does not determine the exchanger model, plate pattern or count, tube layout, channel arrangement, pressure drop, nozzle sizing or mechanical dimensions, and it does not account for phase change, non-Newtonian behaviour or unusual physical properties. Final selection requires review of the actual working conditions, fluid properties, allowable pressure drop, fouling behaviour and design code by an engineer.
Next steps
Work through the heat exchanger selection guide to fix the construction, check the materials and corrosion guide for the alloy, compare options in plate heat exchanger vs shell and tube, and see what moves price in the heat exchanger cost guide. When your figures are ready, send them for an engineered selection or contact our engineering team.
Need a Heat Exchanger for Your Project?
Send your working conditions, drawing or datasheet. Blair will review your request and help confirm the next step.