U.S. fire-protection sheets usually list pressure in pounds per square inch (psi), while many metric notes, pump nameplates, and international datasheets use bar. Using the standard conversion, 1 bar = 14.503773773 psi (exactly 105 Pa), so psi ÷ 14.5038 = bar and bar × 14.5038 = psi. This page is a free browser converter either direction. It is for learning and quick checks—not a substitute for the criteria adopted by your authority having jurisdiction, manufacturer data, a sealed hydraulic calculation, or review by a licensed design professional. It is not a design stamp and not a PE seal.
How the conversion is used
- Confirm which unit your source report or datasheet uses (psi on most U.S. flow-test and sprinkler sheets; bar on many metric / international sheets).
- Convert with 1 bar = 14.5038 psi: Pbar = Ppsi / 14.5038, or Ppsi = Pbar × 14.5038.
- Keep the same pressure meaning (static, residual, rated pump pressure, or demand) when you switch units.
- After units match, continue with head conversions, hydrant, tank, or pump sketches in consistent units.
Free calculator
Educational approximation only. Uses 1 bar = 14.503773773 psi. Nothing you enter leaves your browser. For freshwater head conversions see PSI to feet of head and feet of head to PSI. For elevation sketches see the elevation pressure calculator. Pump demand vs supply sketches live in the Fire Pump & Tank Sizing workbook.
Worked example
A pump rated at 50 psi: 50 / 14.5038 ≈ 3.45 bar. Conversely, 10 bar × 14.5038 ≈ 145.0 psi. Always confirm the source unit and check the result against the adopted edition, manufacturer data, and AHJ—not this page alone.
Next steps: convert head with the free PSI to feet of head calculator or feet of head to PSI calculator, sketch elevation with the elevation pressure calculator, check pump demand with the fire pump curve check, and run full pump and tank tables in the Fire Pump & Tank Sizing workbook ($49). For sprinkler segment friction, use the Sprinkler Pipe Friction Loss workbook ($29).