SettingsSettings for this calculationUS
The load carried down through a single scaffold leg.
Include the scaffold's own dead load plus the working platform load and materials tributary to that leg. Get this from the scaffold's design/load rating, not a guess.
The actual ground-contact area under the leg — the base plate alone, or the base plate plus a sole board if used.
A bare base plate is typically only about 150mm x 150mm (0.0225 m²); adding a sole board spreads the load over a much larger area and sharply reduces bearing pressure.
The allowable ground bearing capacity at this location.
OSHA does not publish a universal allowable bearing value — this must come from a geotechnical report or a competent person's assessment of the actual site soil/surface conditions. US geotechnical reports and IBC Table 1806.2 state presumptive bearing in pounds per square FOOT, which is exactly what this field shows on an imperial page — type the tabulated figure straight in, with no conversion at all. On a metric page the field is in kPa: multiply psf by 0.04788, so 3,000 psf is 143.6 kPa, 2,000 psf is 95.8 kPa and 1,500 psf is 71.8 kPa. This page states the applied pressure in the same unit, so the two can be read against each other directly.
Applied bearing pressure
2,730 psf
This is a first-pass bearing-pressure screening only (leg load ÷ contact area, vs. a user-supplied allowable value). It does NOT verify overall scaffold stability, tie-in/guying requirements (OSHA 1926.451(c)(1), 4:1 height-to-base rule), component structural capacity (1926.451(a)(1), 4x max intended load), sole-board bending/shear adequacy, eccentric or dynamic loading, or site soil variability. Allowable bearing capacity must come from your own geotechnical data or a competent person's site assessment — OSHA does not publish a universal bearing value. Per 1926.451(a)(6) and (f)(7), scaffold design and erection must be under a qualified/competent person; this calculator is not a substitute for that.
- Allowable bearing capacity (user-supplied)
- 3,132.82 psf
They open the calculator with your figures already in it
Scaffold Base Plate Bearing Pressure Calculator: 2,726 psf — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Show calculation logicHide calculation logic
How this was calculated
Formula source(s)
- Applied bearing pressure = Leg Load × 9.81 ÷ Contact Area, the standard geotechnical bearing-pressure check (identical in principle to any shallow footing check) applied to a scaffold base plate or sole board. Per OSHA 29 CFR 1926.451(c)(2), scaffold footings must be 'level, sound, rigid, and capable of supporting the loaded scaffold without settling or displacement' — OSHA does not publish a universal allowable bearing value or leg load (per OSHA Standard Interpretation 2000-08-01, mudsill/footing sizing must be based on actual site soil conditions judged by a competent person).
Inputs used
- Scaffold Leg Load
- 660 lb
- Base Plate or Sole Board Contact Area
- 0.24 sq ft
- Allowable Ground/Soil Bearing Capacity (from Geotechnical Data or Competent Person's Assessment)
- 3132.82 psf
Intermediate steps
- Allowable bearing capacity (user-supplied)
- 3,132.82 psf
Confidence note: This is a first-pass bearing-pressure screening only (leg load ÷ contact area, vs. a user-supplied allowable value). It does NOT verify overall scaffold stability, tie-in/guying requirements (OSHA 1926.451(c)(1), 4:1 height-to-base rule), component structural capacity (1926.451(a)(1), 4x max intended load), sole-board bending/shear adequacy, eccentric or dynamic loading, or site soil variability. Allowable bearing capacity must come from your own geotechnical data or a competent person's site assessment — OSHA does not publish a universal bearing value. Per 1926.451(a)(6) and (f)(7), scaffold design and erection must be under a qualified/competent person; this calculator is not a substitute for that.
What this calculation does not cover
- Treats the leg load as concentric on the plate. A leg out of plumb, or a plate not bearing flat, concentrates the load on one edge and the real peak pressure is higher than load ÷ area — which is the case that punches a sole board into soft ground.
- Assumes the full contact area bears. A base plate on uneven ground, or a sole board that has begun to bridge, carries on part of its area, and the figure you entered is the plate's size rather than what is actually in contact.
- Static load only. Nothing here accounts for material being landed on a lift, wind uplift, or the out-of-balance loads present while the scaffold is being erected or struck.
- Ground does not stay as it was measured. An allowable bearing figure taken in dry weather is not the figure after a week of rain, after a trench is opened alongside, or over a backfilled service.
Add the equipment this sizes
This result is a specification — 2,730 psf — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Applied bearing pressure = Leg Load × 9.81 ÷ Contact Area, the standard geotechnical bearing-pressure check (identical in principle to any shallow footing check) applied to a scaffold base plate or sole board. Per OSHA 29 CFR 1926.451(c)(2), scaffold footings must be 'level, sound, rigid, and capable of supporting the loaded scaffold without settling or displacement' — OSHA does not publish a universal allowable bearing value or leg load (per OSHA Standard Interpretation 2000-08-01, mudsill/footing sizing must be based on actual site soil conditions judged by a competent person).
Cite this page
Your workspace
Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.