Forklift attachment capacity calculator

estimate_upper_bound = (rated_capacity × rated_load_center) / (rated_load_center + attachment_lost_load_center); actual net capacity = value on the OEM revised capacity plate for the truck + attachment combination (always lower once attachment weight is included)

Supralift: an attachment both moves the load center and adds dead weight, and the remaining capacity must be shown on a capacity label. OSHA 1910.178(a)(5) requires the truck to be marked with the attachment and the approximate weight of the truck-attachment combination. The site must present the result as an upper bound and instruct users to get the revised plate from the truck OEM or dealer. No source found gives a published formula for subtracting attachment weight (ANSI/ITSDF B56.1 text not accessed).

Worked example: 5,000 lb at 24 in with an attachment adding 4 in of lost load center: 120,000 / 28 = 4,286 lb upper bound before attachment weight.

max_load_moment = rated_capacity × rated_load_center; revised_capacity = max_load_moment / new_load_center

Same math as OSHA's field calculation, expressed as load moment. Raymond West: assumes uniform, centered loads; non-uniform loads reduce capacity more than calculated. Does not account for the attachment's own weight; OSHA 1910.178(a)(4)-(5) requires manufacturer approval and a revised plate for capacity-affecting changes.

Worked example: Raymond West: 5,000 lb x 24 in = 120,000 in-lb; with 60 in forks the load center becomes 30 in, so 120,000 / 30 = 4,000 lb.