Well Pump Size Calculator
Find the right pump quickly with this well pump size calculator guide. Learn how to calculate the correct pump size for your home or property. Avoid low pressure, pump failure, and wasted energy with accurate sizing.
Pump Sizing Tool
How to Use a Well Pump Size Calculator
Using a well pump size calculator is simple and fast. Follow these steps:
Step-by-Step Instructions
- Enter total water demand: Count fixtures (showers, sinks, toilets) and estimate gallons per minute (GPM).
- Measure vertical lift: Calculate distance from water level to surface.
- Add pressure requirement: Standard home pressure = 40–60 PSI.
- Include pipe length: Add total horizontal pipe distance.
- Input friction loss: Use pipe size and material to estimate loss.
- Click calculate: The tool shows required pump size (HP) and flow rate.
How to Calculate Well Pump Size
You can manually calculate well pump size using this method.
Step 1: Calculate Water Demand (GPM)
Estimate total usage:
- Shower = 2.5 GPM
- Faucet = 1.5 GPM
- Toilet = 2–3 GPM
Example:
2 showers + 2 faucets + 1 toilet
= (2×2.5) + (2×1.5) + (1×3)
= 5 + 3 + 3 = 11 GPM
Step 2: Calculate Total Dynamic Head (TDH)
Convert PSI to feet: Pressure Head = PSI × 2.31
Example:
- Vertical Lift = 100 ft
- Pressure = 50 PSI → 50 × 2.31 = 115.5 ft
- Friction Loss = 20 ft
TDH = 100 + 115.5 + 20 = 235.5 ft
Step 3: Determine Pump Size
Match GPM and TDH to pump specs.
Example Result:
- Flow Rate = 11 GPM
- TDH = 235.5 ft
Recommended Pump:
- About 1.5 HP well pump
Well Pump Size Conversion Chart
| Household Size | Flow Rate (GPM) | Typical TDH (ft) | Pump Size (HP) |
|---|---|---|---|
| Small (1–2) | 5–8 GPM | 100–150 ft | 0.5 HP |
| Medium (3–4) | 8–12 GPM | 150–250 ft | 1 HP |
| Large (5–6) | 12–18 GPM | 200–300 ft | 1.5 HP |
| Very Large | 18–25 GPM | 250–400 ft | 2 HP |
Note: Actual sizing depends on well depth and pipe conditions.
Frequently Asked Questions (Well Pump Size Calculator)
A well pump size calculator helps you find the correct pump size based on water demand, depth, and pressure.
A small pump causes low water pressure and poor performance. It may fail quickly due to overload.
Yes, but it wastes energy and increases system wear. Always choose the correct size instead of oversizing.
Most homes need 8–12 GPM. Larger homes may need 15+ GPM.
TDH is the total resistance the pump must overcome. It includes lift, pressure, and friction loss.
A 1 HP pump usually handles depths between 150–300 feet, depending on system design.
Yes. Longer pipes and smaller diameters increase friction loss and require a stronger pump.
Yes. Higher pressure requirements increase total head and pump size.
You can, but professionals ensure correct sizing and safe installation.
It provides a strong estimate. Always confirm with pump performance charts.