Total Dynamic Head
Also known as TDH · pump head required
Worked example: 30 m TDH less 2400 cm static and 0.4 m velocity → 5.6 m friction. Press Try an example to run it live, then adjust anything.
Enter your known values, leave one input blank, and solves for the missing one. Tap a variable’s symbol to see what it means, with a typical value. Change any unit and the answer follows.
Where Total Dynamic Head fits
- Pump power and efficiency7 formulas
- Heads in a piping system6 formulas
See also
Velocity Head (h = v²/2g): Both use velocity head.Pump Operating Point: Both use static head.Pump System Curve: Both use static head.Pump Affinity Law: Head vs Impeller Diameter: Both use total dynamic head.Pump Affinity Law: Head vs Speed: Both use total dynamic head.Pump Brake Horsepower: Both use total dynamic head.9 more related
Pump Specific Speed (Ns): Both use total dynamic head.Pump Water Horsepower: Both use total dynamic head.Darcy–Weisbach Head Loss: Both use friction head.Hazen–Williams Head Loss: Both use friction head.Minor Loss from K Factor: Both use friction head.Net Positive Suction Head Available (NPSHa): Both use friction head.Energy Balance Between Two Sections with Losses: Both use friction head.Energy Loss in a Hydraulic Jump: Both use friction head.Hydraulic Gradient: Both use friction head.Total dynamic head →
UniversityFluid Mechanics, HVAC & Refrigeration
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Total Dynamic Head explained
Total dynamic head is the pump's job description in a single number. Lift the water 85 ft, lose 22.5 ft pushing it through the pipe, and hand it over with 1.5 ft of velocity head still on board, and the pump must produce 109 ft. Every pump selection begins here: TDH sets the y-coordinate of the duty point, design flow sets the x-coordinate, and the curve that passes closest to that point through its best-efficiency region wins the job.
The recurring mistake is measuring static head from the pump instead of between the two liquid surfaces. If the supply tank is flooded above the pump, that submergence subtracts from static head: a fact worth real money on a long transfer line. And do not double-count: many engineers fold velocity head into the friction allowance, which is fine for water systems where it is a fraction of a foot, but sloppy on high-velocity or short-run systems where it can be several percent of the total.
Total Dynamic Head formula
- = Total dynamic head (m)
- = Static head (m)
- = Friction head (m)
- = Velocity head (m)
Pump power and efficiency
7 formulasWater horsepower, brake horsepower, pump efficiency, NPSH available and specific speed — sizing the motor and keeping the impeller wet.
Heads in a piping system
6 formulasPressure head, velocity head, static fill pressure and total dynamic head — the feet of water a pump and a gauge are each talking about.
Cite this page
formula.expert. (2026, October 16). Total Dynamic Head Formula & Calculator. https://formula.expert/solvers/total-dynamic-head
https://formula.expert/solvers/total-dynamic-head