Calculate Total Dynamic Head (TDH) for centrifugal and positive displacement pumps. Includes static head, friction losses, pressure head and optional velocity head.
Total Dynamic Head = Static Head + Friction Losses + Pressure Head + Velocity Head
All head values in meters of fluid column.
Vertical elevation difference (discharge level − suction level). Positive when pumping uphill.
Total head loss due to pipe friction + fittings + valves.
Required gauge pressure at discharge (0 for open discharge).
The value must be greater than zero.
Usually small (v²/2g). Can be left as 0 for most applications.
The value must be greater than zero.
Recommended 5–15 % extra capacity.
1.0 for water. Affects pressure ↔ head conversion.
Total equivalent length of pipe.
Internal diameter.
Design flow rate.
PVC≈150, Steel≈130–140, Old CI≈100.
Typical 0.60 – 0.85 (enter as decimal).
Total Dynamic Head (TDH)
Without margin: 33.50 m
Equivalent Pressure
3.61 bar
Hydraulic Power
6.45 kW
Static (elevation) head
Friction + minor losses
Pressure head requirement
Velocity head difference
Total Dynamic Head
Reuse the calculation in your own workflow.
def calculate_tdh(static_head, friction_loss, pressure_head=0, velocity_head=0, margin_pct=0):
"""
Total Dynamic Head (m)
TDH = Hs + Hf + Hp + Hv
Optional safety margin applied at the end.
"""
tdh = static_head + friction_loss + pressure_head + velocity_head
if margin_pct > 0:
tdh *= (1 + margin_pct / 100)
return tdh
# Example
Hs = 25 # m
Hf = 8.5 # m
Hp = 0.00 # m (from pressure)
Hv = 0 # m
margin = 10 # %
tdh = calculate_tdh(Hs, Hf, Hp, Hv, margin)
print(f"Total Dynamic Head: {tdh:.2f} m")function tdh = calculate_tdh(Hs, Hf, Hp, Hv, margin_pct)
% Total Dynamic Head (meters)
if nargin < 3, Hp = 0; end
if nargin < 4, Hv = 0; end
if nargin < 5, margin_pct = 0; end
tdh = Hs + Hf + Hp + Hv;
if margin_pct > 0
tdh = tdh * (1 + margin_pct/100);
end
end
% Example
Hs = 25;
Hf = 8.5;
Hp = 0.00;
tdh = calculate_tdh(Hs, Hf, Hp, 0, 10);
fprintf('Total Dynamic Head: %.2f m\n', tdh);=Hs+Hf+Hp+HvQuickly calculate and analyze parameters for your ohms law requirements.
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A booster pump selected only on static head failed to deliver design flow to the top floors. Friction losses in the long vertical riser and pressure-reducing valves had been omitted from the original TDH calculation.
Always include the full friction path and any pressure requirements. Static head alone is never sufficient for pump selection.
A self-priming pump was installed with 6 m suction lift. After adding the suction pipe friction the available NPSH dropped below the required NPSH, causing severe cavitation and impeller damage within weeks.
TDH and NPSH must be evaluated together. Suction-side losses reduce available NPSH even if they increase TDH only slightly.
TDH is the total head (in meters or feet of fluid) that a pump must produce to overcome elevation, friction, pressure and velocity differences in the system.
Head (m) ≈ Pressure (bar) × 10.197 / SG. For water (SG = 1) roughly 1 bar ≈ 10.2 m.
Yes. A 5–15 % margin is standard practice to account for aging pipes, future flow increases and calculation uncertainties.
Velocity head is usually negligible (< 0.5 m) in most industrial systems. It becomes significant only at very high velocities or when comparing different pipe diameters.