Hello you can manually measure the area through some measurements, please to check the "measure /Dimension" section : [https://docs.easyeda.com/en/PCB/PCB-Tools/index.html#Measure-Dimension](https://docs.easyeda.com/en/PCB/PCB-Tools/index.html#Measure-Dimension) I don't think that this will be a parameter to calculate the Reflow temperature for soldering since not only the surface area to measure but also the copper thickness which is changeable too and temperature requirement for 20mm² copper 1 oz of a 0.0175mm thickness is not the same for 20mm² copper 2 oz of a 0.035mm thickness. But still a good suggestion from you.

Is this question about: 1. thermal requirements to work out reflow temperature profiles; 2. or is it about working out the effective thermal resistances for on-board heasinking of things like surface mounted power MOSFETs, rectifiers and high power LEDs? This page will help with (2): [https://www.daycounter.com/Calculators/Heat-Sink-Temperature-Calculator.phtml](https://www.daycounter.com/Calculators/Heat-Sink-Temperature-Calculator.phtml) "For surface mount (SMT) parts, where the PCB copper is used as a heat sink, for 1 ounce copper the heat dissipation asymptotically approaches 1 square inch, in other words, having a PCB heat sink greater than 1 inch doesn't do you any good. There are some tricks that can help, such as placing vias, into the pad, so that heat is transferred to the bottom layer as well. " Adding copper on both sides and, if multilayer, on the inner layers helps too. and the table of **Thermal Resistance for PCB Copper** at the end of the page: Thermal Resistance for PCB Copper | | | | --- | --- | | Heat Sink | Thermal resistance (°C/Watt) | | 1 sq inch of 1 ounce PCB copper | 43 | | .5 sq inch of 1 ounce PCB copper | 50 | | .3 sq inch of 1 ounce PCB copper | 56 | This topic may help too: [https://easyeda.com/forum/topic/How-to-place-multiple-vias-in-a-PCB-footprint-a34cf68d58414138898a56de60abd8c1](https://easyeda.com/forum/topic/How-to-place-multiple-vias-in-a-PCB-footprint-a34cf68d58414138898a56de60abd8c1) More on the subject of the heatsinking effectiveness of a PCB: [https://www.onsemi.com/pub/Collateral/AND9596-D.PDF](https://www.onsemi.com/pub/Collateral/AND9596-D.PDF) [https://www.heatsinkcalculator.com/blog/](https://www.heatsinkcalculator.com/blog/) [https://www.ti.com/design-resources/design-tools-simulation/models-simulators/pcb-thermal-calculator.html](https://www.ti.com/design-resources/design-tools-simulation/models-simulators/pcb-thermal-calculator.html) [http://www.claredot.net/en/sec-Electronics/pcb-heatsink.php](http://www.claredot.net/en/sec-Electronics/pcb-heatsink.php)

Might need to read this too: [https://easyeda.com/forum/topic/How-to-avoid-DRC-errors-when-connecting-to-PCB-Footprints-a-k-a-PCB-Libs-90bf944fe3644b21a7d27a9e9d8df8d6](https://easyeda.com/forum/topic/How-to-avoid-DRC-errors-when-connecting-to-PCB-Footprints-a-k-a-PCB-Libs-90bf944fe3644b21a7d27a9e9d8df8d6)

This was primarily aimed at heatsinking requirements for surface-mounted components. I have read some of those articles you posted already but I will check the others. Thanks.

@surgen, Thinking about your original question: there is currently no tool in EasyEDA that calculates the area of a Copper Area, Solid Region or pads. For uniformly covered rectangular areas it is obviously relatively simple to work out but for an arbitrary shaped area that may include incursions from tracks, pads and holes, it is a manual task to estimate the useable or cintributing area.