In short: elevation head is just the height itself — a 20 ft rise is 20 ft of head, no calculation needed. Converted to pressure, that same 20 ft is worth about 8.65 psi for fresh water at 20°C. As a rule of thumb, every foot of elevation is worth roughly 0.433 psi. Use the calculator above for your exact height and fluid.
These figures are planning aids for hydraulic design. For code-required pump or system sizing, confirm with a licensed engineer.
How to calculate elevation head
Elevation head is the simplest of the three terms in Bernoulli's equation — unlike pressure head or velocity head, it needs no formula, just the height itself:
What makes elevation head useful is converting it into the pressure it represents, using the hydrostatic pressure equation:
Worked example. 20 ft of elevation change, fresh water at 20°C (density 998.2 kg/m³): h = 20 × 0.3048 = 6.096 m. P = 998.2 × 9.80665 × 6.096 = 59,674 Pa, which converts to 8.655 psi (59.67 kPa) — the calculator's default result.
The 0.433 rule. You'll often see "0.433 psi per foot of head" (or its inverse, "2.31 ft of head per psi") used as a quick shortcut for fresh water. It's a rounded version of the same calculation above, close enough for most planning work, but this calculator uses the exact temperature-based density so you can see precisely how much a fluid or temperature change moves the number.
Why height and fluid type change the answer
Height in ft or m is fluid-independent. A 20-foot rise is 20 feet of head whether you're moving water, seawater or diesel — head is a pure geometric measurement of the vertical distance.
Pressure depends on density. Because P = ρgh, a denser fluid produces more pressure for the same height. Seawater, at roughly 1,025 kg/m³ versus fresh water's 998, produces about 2.6% more psi for an identical elevation change — switch the water type above to see the exact difference.
Temperature has a small effect on fresh water. Water is slightly less dense as it warms, so the same height converts to marginally less pressure at higher temperatures. The effect is small — well under 1% between 10°C and 30°C — but the calculator's advanced temperature field captures it exactly.
Reference: elevation head to pressure (fresh water, 20°C)
Every value matches what the calculator returns for the same height at the default water type and temperature.
| Height | psi | kPa |
|---|---|---|
| 5 ft | 2.164 | 14.92 |
| 10 ft | 4.327 | 29.84 |
| 20 ft (default) | 8.655 | 59.67 |
| 30 ft | 12.982 | 89.51 |
| 50 ft | 21.637 | 149.18 |
| 75 ft | 32.456 | 223.78 |
| 100 ft | 43.275 | 298.37 |
Worked examples
Rooftop tank, fresh water
8.655 psi
A tank sitting 20 ft above its point of use (the calculator's default) provides about 8.655 psi of static pressure at the outlet before any friction loss.
Same height, seawater
8.885 psi
The same 20 ft column of seawater (density about 1,024.7 kg/m³) produces roughly 2.6% more pressure — 8.885 psi instead of 8.655.
100 ft well depth
43.275 psi
A submersible pump 100 ft down must overcome about 43.3 psi of elevation head alone to lift water to the surface, before friction losses.
What this calculator doesn't include
Friction loss. Elevation head is only one term of total head. Pipe friction adds its own loss along the way — see the friction loss calculator to add that in.
Velocity head. The kinetic-energy term in Bernoulli's equation is usually small for typical water systems, but for a full picture see the velocity head calculator.
Total dynamic head for pump sizing. To combine elevation head with friction loss and any required discharge pressure into one pump-sizing figure, see the total dynamic head calculator.
Frequently asked questions
What is elevation head?
Elevation head is the vertical height between two points in a water system, expressed as "head" — the same units used for pressure and velocity in Bernoulli's equation. It is the simplest of the three head terms: elevation head is just the height itself, with no calculation needed beyond a unit conversion.
How is elevation head different from pressure head?
Elevation head is a height — a physical distance you could measure with a tape measure. Pressure head is that same height converted into the pressure a column of fluid of that height would exert (or need) at its base. This calculator shows both: the height as head (ft or m) and its equivalent as pressure (psi, kPa or bar).
Does fluid type affect elevation head?
The elevation head itself, in feet or meters, does not depend on the fluid — 20 ft of height is 20 ft of head whether it's fresh water, seawater or oil. But the equivalent pressure does depend on fluid density, since pressure equals density times gravity times height. Denser fluids like seawater produce more psi for the same height.
What is the 0.433 psi per foot rule?
It's a widely used shortcut for fresh water: every foot of elevation is worth about 0.433 psi (or, going the other way, about 2.31 ft of head per psi). It's a rounded version of the same density-based calculation this tool performs, close enough for most planning purposes but not adjusted for temperature or fluid type.
How does elevation head fit into total dynamic head?
Total dynamic head for a pump is the sum of elevation head, friction head loss along the piping, velocity head, and any required discharge pressure converted to head. Elevation head is usually the largest single term for systems with significant height change, such as wells, elevated tanks or multi-story buildings.
Does elevation head depend on pipe diameter or flow rate?
No. Elevation head depends only on the vertical height between two points — it is entirely independent of pipe size, flow rate or velocity. Those factors affect friction head loss and velocity head instead, which are separate terms added alongside elevation head to get total head.
Sources & references
- Bernoulli, D. (1738). Hydrodynamica. Argentorati.
- American Water Works Association (AWWA). Manual M11: Steel Pipe — A Guide for Design and Installation.
John Mac, PE
Water Systems Specialist · Austin, Texas
Texas-licensed Professional Engineer with 13+ years in residential water systems and 180+ completed projects. Writes and reviews the calculators on watercalculator.us. Read full bio
Texas PE (2016) · BS Civil Engineering, Hydraulics (2013)