Find a starting size for your passive heat sink. Set the thermal requirements, explore the geometry, and compare designs.
Vertical fins · Natural convection + radiation · Full-base heat source↓Correct the highlighted values to calculate a new design.
Schematic only. Fin count may be visually simplified; use the calculated dimensions.
Assumes an isothermal, highly conductive heat sink with heat spread across the full base. Small chips, interface resistance, enclosures and fan cooling need a more detailed analysis.
Save up to three concepts to see the trade-offs side by side.
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Change a dimension, save a concept, then compare.A transparent first pass for passive, straight-fin heat sinks. Useful for sizing a concept before detailed thermal analysis.
Read the fin-spacing reference ↗The Bar-Cohen–Rohsenow correlation estimates the convection-optimal gap for vertical, isothermal parallel fins. Air properties are approximated at the mean air/base temperature and 1 atm. The smallest integer fin count that meets the heat load is selected.
Radiation uses a projected-envelope approximation to limit double counting between facing fins. The gap optimizes convection under thin-fin assumptions; it is not a global optimum for combined radiation, volume or cost.
Fin efficiency, spreading/contact resistance, junction temperature, nearby walls, altitude and manufacturing limits are not solved. Base thickness affects geometry and exposed edge area, not a conduction calculation. Validate the actual design with analysis and testing.
Export your concept and include the CAD model, material, surface finish, mounting orientation, heat source footprint, airflow constraints and quantity with your inquiry. The result is a sizing concept, not a manufacturability or thermal-performance guarantee.
Share your drawing, quantity and thermal constraints for a manufacturing review.
Your files stay confidential. An NDA is optional.