Heat Sink Calculator

NOTE! This calculator only applies to a linear transformer+rectifier+filter cap power source. It is not accurate if the raw source is a SMPS.

Use this calculator to select a suitable heat sink for your Superpower regulator. The Max Heat Sink value is the highest thermal resistance allowed for the given conditions. The bigger the thermal resistance, the smaller the heat sink.

Calculator fields have only minimum validation so if the Vrms result has something bizarre (like "NaN"), recheck your input values. If Vin is negative, Vout must also be negative, otherwise the calculations are incorrect.

Superpower type
(select to set drop-out)
Drop out voltage:

Regulator DC input voltage (volts)

Regulator output voltage (volts)

Max Load Current (amps)

Regulator Dissipation (Watts)

Max heat sink °C/W

Heat Sink

The value in the Max heat sink °C/W box shows the maximum thermal resistance for a heat sink on a Superpower with the given Vin. The heat sink calculation assumes a 75°C temperature increase of the regulator.


  • Input voltage is DC or DC equivalent in Vrms
  • Select SP for current < 500mA, SPJ or SPL for higher currents
  • Calculator only works to 3A
  • Heat sink allows 75°C temperature rise due to power dissipation

Can this calculator be used for any voltage regulator?

It can be used for any series voltage regulator if you know the drop-out voltage. For Superpower Type choose Custom regulator and enter the drop-out value for your regulator at the given load current.