# Well Pump Size Calculator

Size your water system properly with our well pump calculator. Determine the correct GPM and horsepower needed based on your home size and well depth.

## What this calculates

Choosing the right well pump is crucial for maintaining a steady, reliable water supply for your home. If your pump is undersized, you’ll experience poor water pressure whenever multiple fixtures run at the same time. An oversized pump can short-cycle, wearing out the motor much faster. Our well pump calculator is designed to help you select the correct pump for your specific needs, ensuring your system is efficient and hassle-free.

## Inputs

- **Home Size** — options: 1 bedroom / 1 bath (small), 2 bedrooms / 2 baths, 3 bedrooms / 2-3 baths (typical), 4 bedrooms / 3 baths, 5+ bedrooms / 4+ baths (large), Irrigation + home combined — This answers what size well pump do i need for my house
- **Well Depth (total)** (ft) — min 20 — Total drilled depth of the well
- **Pumping Water Level** (ft) — min 10 — Depth to water during pumping (static level + drawdown). Check well log.
- **Elevation Rise to Tank** (ft) — min 0 — Vertical distance from ground level up to the pressure tank
- **Horizontal Pipe Run** (ft) — min 0 — Total horizontal run from well to pressure tank
- **Drop Pipe Size** — options: 3/4 inch (small home, shallow only), 1 inch (standard residential), 1-1/4 inch (deep well / high flow) — Larger pipe reduces friction loss
- **Target Pressure** — options: 30/50 psi switch (40 psi average), 40/60 psi switch (50 psi average, typical), 50/70 psi switch (60 psi, large home)

## Outputs

- **Peak GPM Demand** (gpm) — Gallons-per-minute demand at peak use
- **Total Dynamic Head** (ft) — Sum of lift + elevation + friction + pressure
- **Recommended Pump Size** (HP) — Submersible pump HP rating to meet GPM and TDH
- **Pump Recommendation** — formatted as text
- **Friction Loss** (ft)

## Details

Determining Your Pump Requirements

Sizing a pump correctly requires knowing your well's specific dimensions and your home's peak water demand. We calculate your needs using two main metrics:

- Gallons Per Minute (GPM): We estimate your peak demand by counting the number of water fixtures and appliances in your home. Your pump must supply enough GPM to run multiple fixtures simultaneously.

- Motor Horsepower: We use the depth to your water level to calculate how much horsepower the pump needs to push the water up to the surface and maintain strong pressure in your house.

Submersible vs. Jet Pumps

Based on your well depth, you will need either a submersible pump (which sits deep underwater) or a jet pump (which sits above ground and pulls water up, suitable only for shallow wells).

How to Use the Well Pump Calculator

Start by inputting the number of water fixtures and appliances in your home and the depth of your well or water level. The calculator will instantly estimate the gallons per minute (GPM) your home demands at peak usage and determine the appropriate horsepower required based on your well’s depth. These results guide you to the right pump size before you make a purchase or call a professional.

With just a few details, you’ll get the information you need to ensure a reliable water supply for your home, no guesswork, no stress. Try the calculator now and set your well system up for success.

## Frequently Asked Questions

**Q: How do I calculate my home's required GPM?**

A: A general rule is to count the number of water fixtures and appliances in your home. Your pump should supply one GPM for every fixture to handle peak demand.

**Q: Does the depth of the well affect pump size?**

A: Yes. The deeper the well, the more horsepower the pump needs to push the water up to the surface and maintain good pressure in your house.

**Q: What is the difference between a submersible and a jet pump?**

A: Submersible pumps sit underwater deep inside the well. Jet pumps sit above ground and pull water up through a pipe, but they only work for shallow wells.

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Source: https://vastcalc.com/calculators/construction/well-pump
Category: Construction
Last updated: 2026-04-21