---
title: "Filter Sizing: Calculating Clean Element Delta P"
description: Choosing which filter element you need can be a challenge because there are several factors to consider. One of the factors that should be considered is the differential pressure or Delta P of your filter. Check out this blog post A quick tutorial on calculating clean element Dp and filter element sizing.
---

[Donaldson Hy-Pro Lube & Hydraulic Filtration Industry Blog ](https://www.hyprofiltration.com/blog)

# [Filter Sizing: Calculating Clean Element Delta P](https://www.hyprofiltration.com/blog/bid/358065/filter-sizing-calculating-clean-element-dp)

 Written by [Hy-Pro Marketing](https://www.hyprofiltration.com/blog/author/hy-pro-marketing) | Wed, Nov. 19, 2014

Choosing the best filter element size and media for a specific application can be tricky. You want media that is tight enough to help you reach your target ISO code. However, if you choose a media that is too tight for your application, the element differential pressure (Delta P or ΔP) will rise too quickly and you will be replacing elements far too frequently.

To prevent these situations you should always calculate clean element Delta P whenever changing the filter media or manufacturer.

## Step 1: Gather Necessary Information

Before you start, you'll need to gather a few pieces of essential information. They are:

1. Flow rate
2. Lowest temperature  
   *What is the lowest temperature this oil will reach during shutdown, transfer, etc? (This will be used to calculate maximum viscosity in centistokes.)*
3. Specific gravity of the fluid
4. Filter element ΔP factor

## Step 2: Viscosity Chart Calculations 

Use a [viscosity chart](https://www.hyprofiltration.com/viscosity-chart-/) to calculate the maximum viscosity of the fluid at its lowest temperature in centistokes.

## Step 3: Calculate the Delta P 

Use the information you have gathered to solve the equation below for clean element Dp.

 

And that should be it for calculating your clean element Delta P. If you have any questions, please let us know if the comments below. 

Next Step: Use our free [viscosity calculator](https://www.hyprofiltration.com/calculators).

[View full post](https://www.hyprofiltration.com/blog/bid/358065/filter-sizing-calculating-clean-element-dp)

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