W-4 update for 2018. Married with 3 kids, how many allowances should I claim on my W-4 ? Should I claim more than 1 or more ? and what would be the cons and pros

[SteamTrain]

There is no way for us to know your income situation, or what your other deductions are either.

SO just leave your W-4 alone until the IRS issues their new Online W-4 calculator (would expect it by the end of Feb).

An extra month with your old settings in place won't be critical.