ONE FORMULA, ONE ANSWER
Net Radiation Heat Transfer Calculator
Check radiative heat loss between a small gray surface and large surroundings. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Net radiative heat transfer rate Q̇_net
Enter values and select Calculate.
Q̇_net = ε σ_SB A (T_s⁴ − T_sur⁴)
Assumptions
Use A>0 and both absolute temperatures above 0 K. Assume a small diffuse gray surface surrounded by large isothermal surroundings with a view factor of one. Celsius inputs are converted to kelvin before taking fourth powers.
Displayed values are floating-point approximations. Measurement uncertainty and design safety factors are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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