Outrigger pad size calculator
Minimum outrigger pad area (equalization method): pad_area_sqft = outrigger_force_lb / ground_bearing_capacity_psf; square pad side = sqrt(pad_area). Enter your numbers below; the formula and its source are shown under the result.
The pad must be stiff enough to spread the load over its whole area. Get the allowable bearing pressure from a ground assessment; never guess it.
The formulas
pad_area_sqft = outrigger_force_lb / ground_bearing_capacity_psf; square pad side = sqrt(pad_area)
DICA (an outrigger pad maker) calls this the equalization method: the area needed to spread a force over a given ground bearing capacity. It assumes the pad spreads the load evenly; the side of a square pad is our arithmetic.
Worked example: DICA: an outrigger force of 140,000 lb needs a 56 sq ft pad on 2,500 psf ground (140,000 / 2,500 = 56).
[src]rule: use spreader pads under all outriggers/stabilisers unless risk assessment says otherwise
IPAF also offers a Spreader Pad Calculator for boom-type MEWPs supported on outriggers; the ground strength should be assessed first.
Worked example: n/a
[src]Estimate only. The capacity on the machine's data plate is the legal limit; never exceed it.
Sources
- American Cranes & Transport: Setting up for Success Part II (DICA, March 2016) (retrieved November 6, 2026)
- Ground Conditions Guidance, TE-2003-0225-1-en (IPAF) (retrieved November 6, 2026)