Software to calculate your PC's power consumption

Hello.

You can check your CPU consumption using HW Monitor.
The consumption of other components will rely on an estimate of their maximum consumption. There are several ways to find this out.

In official tech sheets, this information is generally provided. ATI and Nvidia offer it on their site for their GPUs. AMD and Intel do the same for their processors.

For the rest, the data is generally quite similar across models. Motherboards of the same level will consume roughly the same amount for different models and brands, and the same goes for hard drives (7200rpm = 1 level of consumption, 10kRPM as well).

To unify all this, you can look at estimation pages that are generally provided by power supply manufacturers. You will need to know the details of your configuration pieces, as well as being aware of your usage habits.
My favorite is the one from Antec, which is very comprehensive and quite honest, but there are others; you can find them here:

https://outervision.com/power-supply-calculator
https://www.commentcamarche.net/informatique/composants/1661-calculer-la-puissance-necessaire-d-une-alimentation-de-pc/