Recirculation Pump Sizing Calculator
Find the right pump size quickly with our recirculation pump sizing calculator. Ensure efficient water flow, lower energy costs, and optimal system performance. Use this guide to calculate accurate pump capacity in simple steps.
Pump Size Estimator
0 GPM @ 0 ft head
How to Use Recirculation Pump Sizing Calculator
Follow these steps to use the recirculation pump sizing calculator:
- Step 1: Enter Flow Rate – Input the required flow rate (GPM or LPM). Use system demand or fixture requirements.
- Step 2: Enter Pipe Length – Add total pipe length (including supply and return lines). Measure in feet or meters.
- Step 3: Select Pipe Diameter – Choose the correct pipe size. This affects friction loss.
- Step 4: Input Elevation Head – Add vertical height difference (if any). Use zero if the system is closed-loop.
- Step 5: Add Friction Loss – Include extra head loss for fittings, valves, and bends. Use standard friction loss charts if unsure.
- Step 6: Calculate Pump Size – Click calculate. The tool gives required pump head and flow rate.
How to Calculate Recirculation Pump Size
Follow this method to calculate recirculation pump sizing manually:
Formula
Step 1: Determine Flow Rate
Example: Required flow = 10 GPM
Step 2: Calculate Pipe Length
Example: Total pipe length = 150 ft
Step 3: Estimate Friction Loss
Assume 4 ft head loss per 100 ft pipe.
Friction
Loss = (150 / 100) × 4 = 6 ft
Step 4: Add Static Head
Closed-loop system → Static Head = 0 ft
Step 5: Calculate TDH
TDH = 0 + 6 = 6 ft
Step 6: Select Pump
Choose a pump that delivers 10 GPM at 6 ft head.
Result:
Required pump size = 10 GPM @ 6 ft head
Recirculation Pump Sizing Conversion Chart
Notes: Increase head for longer pipe runs. Add extra margin for fittings and valves.
| Flow Rate (GPM) | Pipe Size (inch) | Head Loss (ft/100 ft) | Recommended Pump Head (ft) |
|---|---|---|---|
| 5 | 0.5 | 6 | 8–10 |
| 10 | 0.75 | 4 | 6–8 |
| 15 | 1.0 | 3 | 5–7 |
| 20 | 1.25 | 2.5 | 4–6 |
| 30 | 1.5 | 2 | 3–5 |
Frequently Asked Questions (FAQs)
It is a tool that helps you calculate the correct pump size based on flow rate and head requirements.
Correct sizing improves efficiency, reduces energy use, and prevents system failure.
TDH is the total resistance the pump must overcome, including friction and elevation.
Yes, in closed-loop systems, static head cancels out and is usually ignored.
Use standard pipe charts based on pipe size, length, and flow rate.
It wastes energy and may cause noise and system wear.
It results in poor circulation and reduced system performance.
Yes, bends, valves, and fittings increase friction loss and must be included.
Flow rate (GPM or LPM) and head (feet or meters).
Yes, it works for both hot and cold water recirculation systems.