Work out pile load capacity instantly with clear inputs, formula shown and shareable results.
A pile carries load two ways: friction along the shaft, the perimeter area times average unit friction, and bearing at the toe, the base area times end bearing pressure. Their sum is the ultimate capacity, and a factor of safety of 2.5 gives the safe working load. Long slender piles are friction-dominated, short piles to rock are end-bearing.
Ultimate capacity
Qu = pi D L x fs + pi D²/4 x qb
Working load
Q safe = Qu / 2.5
Preliminary estimate only. Pile capacity must be established by a qualified geotechnical engineer from site investigation data and confirmed by pile load testing.
Qu = pi D L x fs + pi D²/4 x qb. A pile carries load two ways: friction along the shaft, the perimeter area times average unit friction, and bearing at the toe, the base area times end bearing pressure.
No. Shaft friction peaks at small displacement while end bearing needs much larger movement, which is why some methods apply different partial factors to each.
This calculator takes 4 inputs: Pile diameter, Embedded length, Average skin friction, End bearing pressure. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.