Are you using the new (current) W-4? It's very different from the old form.
https://www.irs.gov/pub/irs-pdf/fw4.pdf
Claiming fewer dependents will mean you have more tax withheld, meaning a smaller weekly pay check and either a larger tax refund or less tax owed.
You should claim the correct number of dependents and allowances for your situation, whatever that is. Read and follow the instructions on both pages of the form.
