Convert Pounds per Square Foot to Standard Atmospheres
Convert Pounds per Square Foot (lbf/ft²) to Standard Atmospheres (atm) instantly and accurately.
Conversion Formula
atm = lbf/ft² × 0.000472541416
About Pounds per Square Foot
One pound per square foot (psf) ≈ 47.88 Pa - the standard structural engineering load unit in US practice. Building codes specify design loads in psf: residential floors 40 psf; office buildings 50-80 psf; assembly areas 100+ psf; snow loads can exceed 100 psf. Wind pressure on building facades, soil bearing capacity for shallow foundations, and lateral earth pressure in retaining walls are all in psf. The related unit ksf (1,000 psf = 47.88 kPa) covers higher-capacity soils and deep foundations. 1 psf = 47.88 Pa.
About Standard Atmospheres
The standard atmosphere (atm) = exactly 101,325 Pa - defined by the 10th CGPM (1954) as the reference air pressure at sea level. Used to define STP (0°C and 1 atm) for gas law and thermochemistry. Chemical equilibrium constants (Kp), Henry's law solubility, and thermodynamic tables are tabulated at 1 atm. ISA aviation standard: sea-level 1 atm / 15°C, pressure halving every ~5.5 km. Diving physics: +1 atm per 10 m depth (fresh water) so 30 m = 4 atm absolute. Diamond formation in Earth's mantle: ~50,000 atm. 1 atm = 101,325 Pa.
Quick Reference Table
| Pounds per Square Foot (lbf/ft²) | Standard Atmospheres (atm) |
|---|---|
| 1 lbf/ft² | 0.000472541 atm |
| 2 lbf/ft² | 0.000945083 atm |
| 5 lbf/ft² | 0.00236271 atm |
| 10 lbf/ft² | 0.00472541 atm |
| 25 lbf/ft² | 0.0118135 atm |
| 50 lbf/ft² | 0.0236271 atm |
| 100 lbf/ft² | 0.0472541 atm |