Social Charges Simulator

I have been working from UK (via my own Ltd Co) as a contractor for a French company for a year or so. We’ve now moved to France and the company would like me to become a full-time employee. They have made an offer and it seems pretty reasonable at first glance.
The offer is 'rémunération brute fixe annuelle '.
I can figure out how much tax I will have to pay from French govt sites so this is not a problem.

My problem is that I’ve not been able to calculate the social charges and the on-line simulators that I’ve used give very different answers (as in affordable or not).

I have a wife (French and currently unemployed) and a son of 5 (financially dependant) if this makes any difference as to what I’d be required to pay.

Does anyone know of a trustworthy / accurate site where I can pump in the ‘salaire brute’ and get a trustworthy answer?

Thanks in advance, Ray

Not to worry, I found it.

https://www.urssaf.fr/portail/home/utile-et-pratique/estimateur-de-cotisations-2019.html?ut=estimateurs