Water pressure head calculator
A water pressure of 50 psi equals 115.332936 feet of head. Enter a gauge reading or a vertical height and get both figures, ready for pump curves, wells and pressure tanks, with the fresh-water assumption stated. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 50
- From
- psi
- Pressure psi
- 50
- Head ft
- 115.332936
- Feet per psi
- 2.306659
- Psi per foot
- 0.433528
This water pressure head calculator converts pressure in pounds per square inch into feet of water head, or converts feet of head back into psi. It is designed for practical work on domestic pumps, well systems, pressure tanks, irrigation layouts, elevated storage, and gravity-fed plumbing. Enter one nonnegative value and identify it as psi or feet; the result reports both measures using a fixed fresh-water engineering convention. The calculation is deterministic, requires no network connection, and clearly states its density and gravity assumption.
How pressure and elevation head relate
Pressure and head describe the same stored hydraulic energy in two useful ways. Pressure in psi tells you the force acting on each square inch, while elevation head tells you how high a column of water could be supported by that pressure. This calculator uses the hydrostatic relationship pressure equals density multiplied by standard gravity and vertical height.
With fresh water represented as exactly 1000 kilograms per cubic meter and standard gravity represented as 9.80665 meters per second squared, one psi corresponds to approximately 2.306659 feet of water head. In the reverse direction, one foot of water head corresponds to approximately 0.433527 psi. Enter a value and set from to psi when you know the gauge pressure, or set from to ft when you know the vertical head.
Results are rounded to six decimal places for stable display and repeatable automated tests. Zero is valid, but negative values are rejected because this home-sizing calculator represents available pressure or elevation rather than signed pressure differences in a hydraulic model.
Using the result for pumps and pressure tanks
For pump selection, feet of head is usually the more useful result because pump curves plot flow against total dynamic head. Do not treat the converted pressure head as the complete system head by itself. A pump may need to overcome the vertical lift from the water source, pipe and fitting resistance at the intended flow, filter or valve losses, and the required residual pressure at the destination.
For a pressure tank or well system, converting the pressure-switch settings can help visualize the equivalent head available at cut-in and cut-out. For example, the difference between two switch pressures represents usable pressure range, but tank drawdown also depends on tank volume, air precharge, and manufacturer data. Check precharge with the water side depressurized and follow the equipment instructions.
The calculator does not select a pump, estimate flow, calculate pipe friction, or determine tank capacity. Instead, it provides one transparent conversion step that can be carried into a complete sizing calculation. Avoid selecting equipment exactly at the calculated boundary; normal engineering practice allows margin for uncertainty, wear, voltage conditions, changing water levels, and future system changes.
Gravity systems, assumptions, and practical limits
In a gravity-fed water system, the relevant height is the vertical difference between the water surface in the source tank and the point where pressure is needed, not the length of the pipe or its slope. Converting that static elevation into psi estimates pressure when water is not flowing. Once a tap, sprinkler, or valve opens, friction through pipes, fittings, filters, meters, and emitters reduces the pressure that remains at the outlet.
Measure elevations consistently, include the lowest expected tank water level, and calculate losses at the design flow before deciding that a gravity system has adequate service pressure. The fixed fresh-water convention is appropriate for ordinary household and irrigation estimates, but actual density changes slightly with temperature and dissolved material. The calculator is not intended for oils, concentrated brines, process fluids, or situations where a precise site-specific density must be used.
It also assumes standard gravity and does not model atmospheric pressure, suction limitations, cavitation, water hammer, or pressure transients. Gauge pressure is normally the useful basis for home water systems because it measures pressure relative to the surrounding atmosphere. Confirm final equipment choices against pump curves, tank documentation, plumbing requirements, and applicable local codes.
Where freeze protection, potable-water safety, structural tank support, or electrical pump installation is involved, use qualified professional guidance rather than relying on a conversion alone.
What you can do with it
Pump curve preparation
Turn a required outlet pressure in psi into feet of residual head before adding elevation and friction losses for pump selection.
Well and pressure tank checks
Compare pressure-switch settings with their equivalent water head while reviewing pump and tank manufacturer specifications.
FAQ
How many feet of water head equal one psi?
Under this calculator's fresh-water and standard-gravity convention, one psi equals approximately 2.306659 feet of water head.
How much psi does one foot of water create?
One foot of water head equals approximately 0.433527 psi under the stated convention.
Is pipe length the same as elevation head?
No. Static elevation head uses vertical height. Pipe length matters separately because it contributes friction loss when water flows.
Can this calculator size a pump by itself?
No. It converts pressure and head. Pump sizing must also consider flow, elevation, friction losses, source conditions, and the pump curve.
What water properties does the calculation assume?
It assumes fresh water at 1000 kg/m3 and standard gravity of 9.80665 m/s2, producing a stable conventional conversion.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/home/water-pressure-head \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":50,"from":"psi"}'const res = await fetch("https://api.kit.forhosting.com/home/water-pressure-head", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 50,
"from": "psi"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/home/water-pressure-head",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 50,
"from": "psi"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/home/water-pressure-head", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":50,"from":"psi"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":50,"from":"psi"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/home/water-pressure-head", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"value": 50,
"from": "psi"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "home.water_pressure_head",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Use the free browser calculator for quick checks or call the API for $0.002 per successful item when the same conversion belongs in a sizing worksheet, field application, or automated design process.
How pressure and elevation head relate
The response always includes pressure_psi and head_ft, so there is no need to change a separate target selector. It also returns the two conversion factors and repeats the physical assumption.
Integration use cases
Gravity-fed water planning
Estimate the static psi produced by a known vertical distance between a tank water surface and a fixture or irrigation zone.