Planning to shift from Malaysia to Singapore

I am planning to shift from Malaysia to Singapore. Can some one please help me to understand what should be the best salary I can opt for. The current offer I have received is for S$50000. Is it good enough for Family of 3 (Me, my wife and 2 yr old kid).

The best salary you can get depends on your education, work experience, the industry you're working in and also your negotiation skills and of course luck.
I assume your offer is S$50000 per year (=4167/month), not per month (in which case you'd not have any financial worries) and you are planning to work on an EP or S-Pass (kinds of work visa).
The minimum salary requirement to bring dependents (spouse and children) is S$6000/month. Thus they would have to get their own visa (e.g. based on their own work, or student pass for the kid) to join you. Also, this minimum salary is needed to have a resonable lifestyle as a family - any less and you'd be poor. Rent (minimum S$2000-2500/month for a family-sized flat) and school fees (S$500/month at public schools, which are difficult for foreign kids to enter, or S$1000-3000/month for private schools) will be your main expenses.

So the salary offered is not sufficient. Thank you for your help. I will renegotiate the terms.

Plkease note that even the S$6000/month minimum salary for bringing dependents will not allow luxuries or savings. Singapore isn't cheap!

Yes will try to negotiate min 10K

To negotiate min 10k from present offer around $4.1k? I never heard such kind of negotiations (more than double), even changing employer, I don't think there could be 125% variance in market rate at higher end. Good luck

I agree. Even negotiating from S$4.1k to S$6k, the minimum you need to bring your family as dependents, would be a great achievement (46% more). If you manage that, please teach me negotiation skills!

The requirement is very niche hence I have the liberty to negotiate. I have connected with few employees of that company they told me the accommodation(2BHK), transport, schooling and relocation expenses will be paid by the company additionally joining bonus will be given. Let us see if I will get through to the interview. Please let me know if there is anything else I need to take care of.

Well, if accommodation and schooling is taken care of by the company, you don't need that much on top. (But of course more is always better.)
Good luck in your negotiations!