Class 4 or Class 5? How to size a box truck you will not outgrow

The most common mistake we see in first-time fleet purchases is buying the truck that fits the current route instead of the route two years from now. The jump from Class 4 to Class 5 typically costs less than $6,000 new and buys 3,000 lb of payload headroom.

Start with your heaviest realistic load, add the body weight, liftgate and driver, then check the math against GVWR. An Isuzu NPR-HD carries a 16-foot box comfortably, but if your loads flirt with its ceiling, the NRR or a Hino L6 is the safer spec.

Resale complicates the picture: Class 4 trucks sell faster used because CDL rules keep the buyer pool large. If you expect to turn the truck over in four years, the smaller chassis can be the better total-cost play even when the payload math says go bigger.