Assuming an investors equity is $400,000 after selling a duplex.
Assuming his tax liability is approximately $140,000 (after depreciation recapture, federal capital gain tax, state capital gain tax and net investment income tax), the amount he would have to pay in taxes etc.
Based on the above, the investor will have $260,000 actual equity (down payment) to reinvest in another property.
If he reinvest into another property, with 25% down ($260,000) and getting a 75% loan ($780,000), he would be able to purchase a property worth $1,040,000
If the same investor did a 1031 Exchange, he would be able to purchase a $1,600,000 property. 25% own payment of $400,000 with a new 75% loan of $1,200,000