Method: Heat-exchanger duty is calculated from: Q = ṁ × c_p × ΔT where: Q = heat-transfer rate ṁ = mass flow rate c_p = specific heat capacity ΔT = absolute difference between inlet and outlet fluid temperatures. With mass flow in kg/s and specific heat in kJ/kg·K, the result is directly obtained in kW. If a second fluid is entered, its heat duty is calculated independently using the same equation. Duty imbalance is calculated as: Imbalance = |Q₁ − Q₂| ÷ ((Q₁ + Q₂) / 2) × 100 In an ideal steady-state heat exchanger with negligible heat losses, the heat lost by one fluid should approximately equal the heat gained by the other. Real measurements may show an imbalance due to heat loss to surroundings, instrument uncertainty, inaccurate flow measurements, changing process conditions or incorrect fluid-property assumptions. This calculator assumes single-phase sensible heating or cooling with approximately constant specific heat. It should not be used directly for boiling, condensation, evaporation or other phase-change duties without using appropriate enthalpy data.