Pricing building costs for new home construction in Central NJ

[Grace G.]

I am seeking bids for a duplex or a single-family home for investment purposes.

The lot sizes vary from 0.47 acres to 1.3 acres and the asking prices for the vacant lots are between 150 K up to 300 K depending upon the town.

How can I determine what is a reasonable building cost for a side-by-side duplex that has 1400 sf on each side or a 2400 sf SFH with either a daylight or walk-out basement?

I have received one quote from a builder that was very detailed and thorough, but it was very high, including profit and overhead fees of about 20%.

Thanks,

Grace