Method for France
Your salary was given to you gross and you would like to know exactly what you will receive at the end of the month? It only takes a simple calculation to determine this.
In France, the percentage of social charges to be withdrawn from his salary, for a CDI, is around 21%.
If you have a gross salary of 1500 euros, you just need to make 1500 * 0.79 = 1185 euros. The figure 0.79 is determined by the fact that at 0% you are at 1. Here the charges are 21% so 1-0.21 = 0.79.
If you want to more accurately determine your take-home pay, use an online converter. The site https://www.salaire-brut-en-net.fr/ offers this tool.