Tools › Units › Calculators › Formula with Units › Example
NIST SP 811 factors: 1,000 lbf on 2 in² = 500 psi = 3.44738 MPa
| Tool | Formula with Units |
| Source | Thompson, A., and Taylor, B. N. (2008). Guide for the Use of the International System of Units (SI). NIST Special Publication 811, National Institute of Standards and Technology, Gaithersburg, MD. Appendix B.8 and B.9 (psi, lbf, in²). |
| Level | Undergraduate |
Problem
A force of 1,000 lbf acts on an area of 2 in². Compute the pressure p = F/A and give it in pascals with an SI prefix and in psi; then compute the same ratio for 1 kN on 1 in² to see mixed-system inputs handled.
Inputs to Enter
- Example select 'Pressure from force and area' (fills F = 1000 lbf, A = 2 in^2, formula F / A, result p in MPa)
- Mixed case typed by hand: F = 1 kN, A = 1 in^2
Answers
- p = 500 psi = 3,447,378.6 Pa, shown as 3.4474 MPa (SP 811: 1 psi = 6,894.757 Pa)
- 1 kN / 1 in² = 1,550,003.1 Pa = 224.81 psi (1 in² = 6.4516 × 10⁻⁴ m² exactly)
- F = m a with 10 kg and 9.80665 m/s² gives 98.0665 N = 22.046226 lbf
Notes
Choose the example in the Example select, which overwrites the variable rows, formula and result unit; the other two cases are typed. Not the default case.