how to calculate hydraulic hose size


Calculating Hydraulic Hose Size: A Comprehensive Guide


When it comes to designing or replacing hydraulic hoses, selecting the appropriate size is crucial for efficient and effective fluid transfer. Calculating the correct hydraulic hose size ensures optimum performance and avoids potential failures or safety hazards. In this article, we will delve into the process of determining the right size of hydraulic hose for your specific application. We will explore factors to consider, formulas to use, and provide practical tips to help you make accurate calculations.

Understanding the Basics of Hydraulic Hose Sizing

To determine the right hydraulic hose size, it's essential to have a basic understanding of hydraulic systems. Hydraulic systems use fluid to transmit power and control machinery or equipment. A hydraulic hose plays a critical role in this process, conveying fluid between different components. These hoses are typically made of synthetic rubber or thermoplastic materials, designed to withstand high-pressure conditions.

Factors to Consider in Hydraulic Hose Sizing

Several factors should be taken into account when calculating hydraulic hose size. These include flow rate, velocity, pressure, temperature, and compatibility with the fluid being transmitted. Let's explore each factor in detail:

2.1 Flow Rate:

Flow rate refers to the volume of fluid passing through the hose per unit of time. It is typically measured in gallons per minute (GPM) or liters per minute (LPM). Calculating the flow rate accurately is essential as it directly impacts hose size selection. You can determine the flow rate by considering the optimum speed and volume of fluid required for your hydraulic system.

2.2 Velocity:

Velocity refers to the speed at which the fluid passes through the hose. It is crucial to maintain an appropriate velocity to avoid excessive pressure drops or turbulence. Generally, velocities between 20 to 30 feet per second (6 to 9 meters per second) are recommended for hydraulic systems. To calculate the velocity, divide the flow rate by the area of the hose's cross-section.

2.3 Pressure:

Pressure is a critical factor to consider while sizing hydraulic hoses. It determines the strength and thickness required to withstand the system's operating conditions. Hydraulic hoses are available in different pressure ratings, typically measured in pounds per square inch (PSI) or bar units. Understanding the maximum and minimum pressure requirements of your system is crucial for selecting the correct hose size.

2.4 Temperature:

The temperature of the fluid being transmitted in the hydraulic system is another important consideration. High temperatures can affect the performance and durability of the hose. Ensure that the chosen hose material can handle the fluid's temperature without any degradation or impairment.

2.5 Fluid Compatibility:

Different hydraulic fluids have varying chemical compositions. It is essential to select a hydraulic hose material compatible with the fluid being transmitted. Incompatible materials can lead to chemical reactions, degradation of the hose, or loss of performance. Consult with experts or refer to manufacturers' guidelines to ensure the compatibility of the hose material with the fluid.

Calculating Hydraulic Hose Size: Step-by-Step Procedure

Now that we understand the critical factors let's walk through the step-by-step process of calculating the hydraulic hose size:

3.1 Determine the Flow Rate:

Start by determining the required flow rate for your hydraulic system. Consider factors such as cylinder speed, motor displacement, or pump flow rate to calculate the flow rate accurately.

3.2 Calculate the Velocity:

Using the flow rate value, calculate the velocity of the fluid in the hydraulic hose. As mentioned earlier, divide the flow rate by the hose's cross-sectional area to determine the velocity.

3.3 Consider Pressure Requirements:

Analyze the maximum and minimum pressure requirements for your hydraulic system. Refer to manufacturers' catalogs or guidelines to select hoses suitable for the specific pressure conditions.

3.4 Evaluate Temperature Range:

Consider the anticipated operating temperature range of your hydraulic system. Ensure that the selected hose material can handle the temperature without any compromise in performance or lifespan.

3.5 Check Fluid Compatibility:

Verify the compatibility of the hose material with the hydraulic fluid being used. Choose a hose material resistant to reaction, degradation, or any adverse effects caused by the fluid.

Practical Tips for Hydraulic Hose Sizing

To ensure accurate hose sizing, consider the following practical tips:

4.1 Consult with Experts:

If you are unsure about any aspect of hydraulic hose sizing, consult with hydraulic system experts or manufacturers. They can provide valuable insights and recommend the most appropriate hose size for your application.

4.2 Test the System:

Before finalizing the hydraulic hose size selection, test the system with the chosen hose size. Monitor the flow, pressure, and overall performance to detect any deviations or issues.

4.3 Account for Future Expansion:

Consider potential future expansion or modifications in your hydraulic system. Select a hose size that allows for scalability and accommodates future requirements without the need for significant redesigning or replacement.

4.4 Regular Maintenance and Inspection:

Periodically inspect and maintain your hydraulic hoses to ensure they remain in optimal condition. Regular maintenance prevents potential hose failures, leaks, or disruptions in the fluid transfer process.


Determining the correct hydraulic hose size is a critical aspect of designing or replacing hydraulic systems. By considering flow rate, velocity, pressure, temperature, and fluid compatibility, you can accurately calculate the appropriate hose size. Remember to consult experts and perform system tests before making a final decision. Taking these precautions will result in a reliable and efficient hydraulic system that meets your specific needs.


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