there's some IRS website or link where you can crunch numbers and figure out how many exemptions to claim to get the most gross with low risk of owing at the end of the year. In case you'd rather go that way than have more withheld and a larger return.
I did this, am single, not sure how many exemptions (more than what the little form your job gives you would have you crunch), my gross was ~ $53K I believe, and my take home was definitely $3K/mo, almost exactly.
Remember if you have medical expenses and expect to hit your deductible to factor this in. I took it right off the top of my yearly predicted take home base when I was budgeting, even though I had to cough it all up in the first 2 months in (mine was ~$3K).
Besides the gov't, the other big thing is your health insurance premium. Mine was ~$150/mo, not sure if dental and vision was in that. I think dental was ~$50, and vision ~$18. Disability was pretty variable and was cheap even for the most coverage I could elect. All told, I think it was ~$200 a month for good coverage and max disability. (My take home was still $3K).
If I had done more with the HSA or whatever to withhold for my medical expenses and be able to write it off tax free, this would have changed the numbers somewhat, not sure by how much. I think I could have put in $4K for the year (which I easily could have used) but not really sure on the amount or rate of withholding there.
TDLR
Calculated minimum to withhold using IRS website, ie max exemptions
~$53K/yr gross
~$3K/mo take home
Difference was gov't withholding, and ~$200 monthly for health etc benefits