Minor Loss Calculator
Enter the loss coefficient and flow velocity to compute the minor (local) head loss in a pipe fitting.
Input Data
Results
At a glance:Minor (local) head loss h_m occurs at pipe fittings and disturbances where flow separates or changes direction. It is modelled as h_m = K·v²/(2g), where K is the loss coefficient (depends on the fitting type — e.g. ~0.5 for a 90° elbow, ~10 for a fully open globe valve but much higher when throttled) and v is the mean flow velocity. These losses are called 'minor' relative to friction loss in long pipes, but with many fittings they can be the majority of total loss.
Formula
Minor head loss: h_m = K·v²/(2g)
$$h_L = K\,\dfrac{v^2}{2g}$$How to Use
- Enter the loss coefficient K.
- Enter the flow velocity v (m/s).
- The calculator returns the minor head loss h_m.
Case Studies
Elbow in a pipe
K = 0.5, v = 2 m/s, g = 9.81.
h_m = 0.5×4/(2×9.81) ≈ 0.102 m.
Four elbows add about 0.4 m of head loss.
FAQ
Why is it called a 'minor' loss?
Historically it is small compared to friction loss in long straight pipes, but at fittings and in short runs it is often the dominant loss. The name is relative, not always small.
Where do K values come from?
From empirical tables for each fitting type and flow condition; they are dimensionless and combined with v²/(2g), the velocity head.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.