Pump Head Calculator
Calculate Total Dynamic Head
Determine the total dynamic head for your pumping system with our free TDH calculator. Input static head, pipe friction losses, and pressure requirements — backed by DEFU's 20+ years of industrial pump engineering.
TDH Calculator
Total Dynamic Head & Unit Converter
How to Calculate Head for a Pump: Complete Guide
Accurately calculating pump head is the most critical step in selecting the right pump — whether for a construction dewatering project, an agricultural irrigation system, or an industrial water transfer operation. An undersized pump wastes energy and fails to deliver required flow; an oversized pump leads to excessive costs and premature wear.
At DEFU, we manufacture centrifugal self-priming pumps, diesel-driven dewatering pump sets, and fire fighting pumps with maximum heads ranging from 15 m to 150 m and flow capacities up to 3,600 m³/h. This guide walks you through every step of the pump head formula so you can confidently match your TDH to the right DEFU pump model.
What Is Total Dynamic Head (TDH)?
Total Dynamic Head (TDH) is the total equivalent height a pump must push liquid, accounting for both vertical lift and energy losses from pipe friction. It is expressed in feet or meters of fluid column and is the primary metric used when reading centrifugal pump performance curves. Every DEFU pump is ISO 9906-tested and ships with verified performance curves, making TDH-based selection straightforward.
Static Head = Static Suction Head + Static Discharge Head (vertical elevation difference)
Friction Losses = resistance from pipe length, diameter, material, and flow rate
Pressure Head = discharge pressure requirement (convert: PSI × 2.31 = ft of head)
Misc. Losses = elbows, valves, check valves, strainers, and other fittings
Step-by-Step: Calculate Pump Head Formula
Step 1: Static Head
Measure the vertical distance from the water source surface to the discharge point. For worst-case scenarios, assume the lowest possible suction level (e.g. maximum drawdown in a mine dewatering application).
Step 2: Friction Loss
Calculate pipe friction using the Darcy-Weisbach or Hazen-Williams equation based on pipe size, length, material, and flow rate. Add equivalent lengths for all fittings.
Step 3: Pressure Head
If discharging into a pressurized system (e.g. a fire fighting sprinkler loop), convert: 1 PSI = 2.31 ft of head (SG = 1.0).
Step 4: Sum All Values
Add all components together. This total is your TDH — use it on the pump curve to select the correct DEFU pump.
Pipe Friction Loss Reference Table
Approximate friction loss per 100 ft (30 m) of straight steel pipe. Values vary by material (PVC, HDPE, cast iron) and pipe condition.
| Pipe Size | 50 GPM | 100 GPM | 200 GPM | 500 GPM |
|---|---|---|---|---|
| 2" (50mm) | 12.4 ft | 45.2 ft | — | — |
| 3" (80mm) | 2.0 ft | 7.2 ft | 26.1 ft | — |
| 4" (100mm) | 0.5 ft | 1.9 ft | 6.8 ft | 38.6 ft |
| 6" (150mm) | 0.1 ft | 0.3 ft | 0.9 ft | 5.2 ft |
| 8" (200mm) | — | 0.1 ft | 0.2 ft | 1.3 ft |
Why Accurate Pump Head Calculation Matters
Overestimated TDH pushes the pump toward runout — increasing NPSHr, risking cavitation, and potentially overloading the motor. Underestimated TDH means insufficient flow, causing downtime and equipment damage. Both scenarios are preventable with accurate calculation. DEFU pumps are performance-tested to ISO 9906 at our in-house facility. Every unit ships with a verified pump curve and is CE / UKCA / TRCU certified.
DEFU Pump Series — Head Range Reference
TX/TH Series Water Pump
Head: 15–80 m | Flow: ≤400 m³/h
Construction dewatering, sewage transfer, general drainage applications.
View Product →JT/JU Self-Priming Sewage Pump
Head: 12–60 m | Flow: ≤300 m³/h
Agriculture irrigation, general water transfer and municipal drainage.
View Product →MP Mine Dewatering Pump
Head: 20–150 m | Flow: ≤800 m³/h
Mining dewatering, high-head industrial pumping and vacuum-assisted transfer.
View Product →Fire Fighting Pump Sets
Head: 20–150 m | Flow: ≤360 m³/h
NFPA20 compliant, UL/FM listed fire pump systems for maximum safety.
View Product →Frequently Asked Questions
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