Water Pressure (Head Height to PSI)

PSI = ft of head × 0.433. Or 1 PSI = 2.31 ft of water column.

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How to use this calculator

  • Pick direction.
  • Enter value.

About this calculator

Water pressure from gravity head: 0.433 psi per foot of vertical column (water density × g × ft). 100 ft elevation tank = 43.3 psi at ground level. Conversely, your home water pressure (50-80 psi typical) corresponds to 115-185 ft equivalent head. Garden hose at street pressure 60 psi = 138 ft virtual height — useful for sprinkler design and water-tower sizing.

Frequently asked

Why 0.433?+
Density of water (62.4 lb/ft³) × 1 ft × (1/144 in²/ft²) = 0.4333 psi.
Typical home water pressure?+
50-80 psi. Below 40: low-pressure problems. Above 80: damaging plumbing. PRV (regulator) limits.
Pump head capability?+
Centrifugal pump rated by max head (ft). 50 ft head ≈ 21.6 psi. Match to system requirements.
Why water towers?+
Provide passive pressure to neighborhood. 100 ft tank gives 43 psi to homes below. No pumps needed at peak.
Pressure ≠ flow?+
Pressure is potential. Flow depends on pipe size + length + obstructions. High pressure + small pipe = low flow.

Related calculators

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Drain Pipe Slope
Slope (in per ft) × run length = total drop. Standard ¼" per ft.
Pump Horsepower for Flow
HP = (GPM × ft head) / (3960 × pump efficiency).
Water Heater Recovery Rate
GPH = (BTU/hr × efficiency) / (8.33 × ΔT). Hot water output rate.
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Pressure psi ↔ bar
1 bar = 14.5038 psi = 100 kPa = 0.987 atm.

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