Convert Pounds per Square Foot to Kilopounds per Square Inch
Convert Pounds per Square Foot (lbf/ft²) to Kilopounds per Square Inch (ksi) instantly and accurately.
Conversion Formula
ksi = lbf/ft² × 6.944444444e-6
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 Kilopounds per Square Inch
One ksi (kilopound per square inch) = 1,000 psi ≈ 6.895 MPa - the standard engineering stress unit in the US. ASTM A36 structural steel: 36 ksi yield, 58-80 ksi tensile. ASTM A325 high-strength bolts: 92 ksi proof load. AISC steel construction tables, FAA/MIL-SPEC aerospace allowables, and ASME Section VIII pressure vessel design all use ksi. Fracture toughness (K_IC) for steels: 50-200 ksi·√in. Convenient because it keeps large structural stresses as manageable 3-digit numbers. 1 ksi = 6.895 MPa.
Quick Reference Table
| Pounds per Square Foot (lbf/ft²) | Kilopounds per Square Inch (ksi) |
|---|---|
| 1 lbf/ft² | 6.944 × 10-6 ksi |
| 2 lbf/ft² | 1.389 × 10-5 ksi |
| 5 lbf/ft² | 3.472 × 10-5 ksi |
| 10 lbf/ft² | 6.944 × 10-5 ksi |
| 25 lbf/ft² | 0.000173611 ksi |
| 50 lbf/ft² | 0.000347222 ksi |
| 100 lbf/ft² | 0.000694444 ksi |