# Minor (Local) Head Loss Calculator (h = K·v²/2g)

Compute the minor (local) head loss and pressure drop for pipe fittings, valves and bends: h_m = K·v²/(2g), ΔP_m = K·ρ·v²/2. Ships typical K values for 14 common components (gate/globe/check/angle/ball valves, 90°/45° elbows, tees, sudden contraction/expansion, sharp entrance/exit); choose a preset or supply a custom K. Supports n identical fittings in series. Returns head loss (m, ft) and pressure drop (Pa, kPa, bar). Density in kg/m³, g/cm³ or lb/ft³.

> Canonical page: https://elysiatools.com/en/tools/minor-loss-calculator

- **Category:** Math & Numbers

- **Keywords:** minor loss, local loss, fitting loss, k factor, loss coefficient, valve loss, elbow, bend, head loss, fluid mechanics, pressure drop, hydraulics, piping, velocity head, dynamic pressure

## Overview

The Minor (Local) Head Loss Calculator estimates head loss and pressure drop caused by pipe fittings, valves, bends, entrances, exits, sudden contractions, and sudden expansions. Enter a loss coefficient K or choose a preset, then provide flow velocity, fluid density, gravity, and the number of identical fittings in series.

## Inputs

- **Component Type** (select): Pick a preset to pre-fill a typical loss coefficient K. The K field below stays user-editable; if you leave K empty the preset's typical value is used.
- **Loss Coefficient K** (number): Loss coefficient K (dimensionless). If left empty and a preset Component Type is selected, the preset's typical K is used. When Component Type is "Custom K", K must be provided. Typical ranges: gate valve ~0.15, globe valve ~10, 90° std elbow ~0.9, sharp exit ~1.0.
- **Velocity v** (number): Mean flow velocity v in the pipe (m/s).
- **Density ρ** (number): Fluid density ρ in the selected Density Unit (default water ≈ 1000 kg/m³).
- **Density Unit** (select)
- **Gravity g** (number): Gravitational acceleration g in m/s² (Earth default 9.81).
- **Quantity n** (number): Number n of identical fittings in series. Total loss = n · K · v²/(2g).
- **Decimal Places** (number)

## When to use

- Estimate local head loss from elbows, valves, tees, and other pipe components.
- Calculate the pressure drop caused by one or more identical fittings in series.
- Compare fitting options using a preset K value or a custom loss coefficient.

## How it works

- Choose a component preset or select Custom K and enter the dimensionless loss coefficient.
- Enter mean pipe velocity, fluid density, gravitational acceleration, and fitting quantity.
- The calculator applies hₘ = n·K·v²/(2g) for head loss and ΔPₘ = n·K·ρ·v²/2 for pressure drop.
- Review head loss in meters and feet, plus pressure drop in pascals, kilopascals, and bar.

## Use cases

- Pipe system design checks for valves, elbows, tees, and other fittings.
- Pump and piping calculations that require local pressure-drop estimates.
- Hydraulics coursework and fluid-mechanics examples involving velocity head and K factors.

## Frequently asked questions

### What does the loss coefficient K represent?

K is a dimensionless coefficient describing the local resistance of a fitting, valve, bend, or flow transition.

### Can I use a preset K value?

Yes. Select a supported component type to use its typical K value. The K field remains editable.

### Can I enter my own K value?

Yes. Select Custom K and provide a nonnegative loss coefficient.

### How does quantity affect the result?

For n identical fittings in series, the calculator multiplies the single-fitting loss by n.

### Which density units are supported?

Density can be entered in kg/m³, g/cm³, or lb/ft³. Results include metric head-loss and pressure-drop units.

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