Forklift Selection Calculator

The derate factor is 24 divided by your load center in inches, so at 48 in the factor is 0.5, and dividing your actual load weight by 0.5 doubles the minimum rated capacity needed at the standard 24-inch center. This reflects a real physical effect: moving a load's center of gravity farther from the fork face creates more tipping moment, so the truck needs proportionally more rated capacity at the standard reference point to safely handle the same weight.

It looks up the required rated capacity against a fixed list of standard class sizes — 3,000, 4,000, 5,000, 6,000, 8,000, 10,000, 12,000, and 15,000 lb — and picks the first one that's greater than or equal to your number, since forklifts aren't manufactured in arbitrary capacity increments. If your required capacity is 5,200 lb, for example, the recommendation jumps to the 6,000 lb class because no standard model sits between 5,000 and 6,000.

The calculator uses aisle width alone as a proxy for maneuverability needs: under 8 ft it recommends a reach truck (type 2), 8 to 12 ft a three-wheel counterbalance (type 1), and 12 ft or more a standard four-wheel counterbalance (type 0). Narrower aisles physically can't accommodate the wider turning radius of a standard counterbalance truck, so tighter spaces push the recommendation toward more compact, maneuverable — and generally more expensive — truck classes.

Free lift is calculated as the lift height in feet converted to inches, but capped at 84 inches — the standard interior clearance height of a shipping container or trailer. Since lift height in feet times 12 reaches 84 at exactly 7 ft, any higher lift height input still reports 84 in for free lift, because that output specifically represents how far the forks can rise before hitting a container ceiling, not the truck's total lift capability.