Heat Exchanger Calculator
LMTD, heat transfer rate and required area
Quick Answer — Heat Exchanger
The Heat Exchanger Calculator is a free online engineering tool that helps you lmtd, heat transfer rate and required area. Enter your values above for instant, accurate results — no signup required. All calculations run privately in your browser.
Material Properties
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Maintained by: Sagar Sahni, Calc Labz | Review: formula checks, worked examples, and periodic updates
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Step-by-Step Formula Derivation
Mathematical derivation for the Heat Exchanger Calculator
Applicable Standards & Codes
Engineering standards referenced by the Heat Exchanger Calculator
Engineering Reference
Learn the theory behind the Heat Exchanger Calculator
Heat exchanger design is based on the fundamental heat transfer equation Q = UAΔTₘ, where Q is the heat transfer rate, U is the overall heat transfer coefficient, A is the surface area, and ΔTₘ is the log-mean temperature difference (LMTD). The LMTD method accounts for the varying temperature difference along the heat exchanger length.
The overall heat transfer coefficient U depends on convection coefficients on both fluid sides and conduction through the tube wall: 1/U = 1/h₁ + t/k + 1/h₂ + Rf₁ + Rf₂, where Rf represents fouling resistances. Shell-and-tube exchangers are classified by TEMA standards into classes R (severe duty), C (moderate), and B (chemical service), each with specific design rules for baffle spacing, tube pitch, and material selection.
Formula & Worked Example
The math behind the Heat Exchanger Calculator
Mathematical Formula
Result = F(x_1, x_2, \dots, x_n)Step-by-Step Worked Example
Frequently Asked Questions
Common questions about the Heat Exchanger Calculator
What is the Heat Exchanger Calculator?
How do I use the Heat Exchanger Calculator?
Is my personal data saved when using this calculator?
Can I use the Heat Exchanger Calculator on my mobile phone?
How accurate is the Heat Exchanger Calculator?
What is the Heat Exchanger Calculator?
The Heat Exchanger Calculator is a free online engineering tool that helps you lmtd, heat transfer rate and required area. Built for accuracy and speed, this calculator uses verified formulas and provides instant results without requiring any signup or registration. All calculations run entirely in your browser, ensuring complete privacy — no personal data is ever sent to our servers.
How to Use the Heat Exchanger Calculator
- Enter Mass Flow Rate: Enter your mass flow rate (in kg/s) in the input field. The calculator will validate your input automatically.
- Enter Specific Heat (Cp): Enter your specific heat (cp) (in kJ/kg·°C) in the input field. The calculator will validate your input automatically.
- Enter Hot Inlet Temp: Enter your hot inlet temp (in °C) in the input field. The calculator will validate your input automatically.
- Enter Hot Outlet Temp: Enter your hot outlet temp (in °C) in the input field. The calculator will validate your input automatically.
- Enter Cold Inlet Temp: Enter your cold inlet temp (in °C) in the input field. The calculator will validate your input automatically.
- Enter Cold Outlet Temp: Enter your cold outlet temp (in °C) in the input field. The calculator will validate your input automatically.
- Enter Overall Heat Transfer Coeff (U): Enter your overall heat transfer coeff (u) (in W/m²·K) in the input field. The calculator will validate your input automatically.
- Enter Effectiveness: Enter your effectiveness (in %) in the input field. The calculator will validate your input automatically.
- View Your Results: The Heat Exchanger Calculator displays your results instantly in the output panel. You will see the primary result along with a detailed breakdown of secondary outputs. Scroll down for charts, interpretations, and expert advice.
Key Features
- Instant Heat Exchanger calculations with real-time updates
- No signup, no registration — 100% free forever
- All calculations happen in your browser — zero data sent to servers
- Works offline as a Progressive Web App (PWA)
- Mobile-friendly responsive design
- Verified engineering formulas updated for 2026
Why Use Calc Labz Heat Exchanger Calculator?
The Calc Labz Heat Exchanger Calculator stands out because it combines accuracy with simplicity. Unlike other online calculators, we provide detailed breakdowns, step-by-step formulas, and actionable advice alongside your results. Our engineering calculators are regularly updated to reflect current rates, rules, and standards for India (2026). Whether you are a student, professional, or just need a quick calculation — Calc Labz delivers reliable results instantly.
Key Terms & Glossary
- Ohm's Law
- V = I × R — Voltage equals Current times Resistance. The fundamental law of electrical circuits.
- Power Factor
- The ratio of real power to apparent power in an AC circuit, ranging from 0 to 1.
- Torque
- A rotational force measured in Newton-meters (N·m) that causes an object to rotate about an axis.
- Reynolds Number
- A dimensionless quantity predicting whether fluid flow is laminar (smooth) or turbulent.