The image above represents knoop hardness number. To calculate knoop hardness number, two essential parameters are needed and these parameters are **Load Applied (P)Â **andÂ **Length of Indenter Tip (l).**

**The formula for calculating knoop hardness number:**

HK =Â ^{14.2P}/_{lÂ²}

Where:

HK = Knoop Hardness Number

P = Load Applied

l = Length of Indenter Tip

Given an example;

Find the knoop hardness number when the load applied is 21 and the length of indenter tip is 3.

This implies that;

P = Load Applied = 21

l = Length of Indenter Tip = 3

HK =Â ^{14.2P}/_{lÂ²}

That is, HK = ^{14.2(21)}/_{(3)Â²}

HK =Â ^{(298.2)}/_{(9)}

HK = 33.13

Therefore, theÂ **knoop hardness numberÂ **isÂ **33.13.**

Read more:Â How to Calculate and Solve for Vickerâ€™s Hardness Number | Mechanical Properties

**Calculating the Load Applied when the Knoop Hardness Number and the Length of Indenter Tip are Given**

P = ^{HK(l2)} / _{14.2}

Where:

P = Load Applied

HK = Knoop Hardness Number

l = Length of Indenter Tip

Let’s solve an example;

Given that, the knoop hardness number is 14 and the length of indenter tip is 2. Find the load applied?

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This implies that;

HK = Knoop Hardness Number = 14

l = Length of Indenter Tip = 2

P = ^{HK(l2)} / _{14.2}

P = ^{14(22)} / _{14.2}

So, P = ^{14(4)} / _{14.2}

P = ^{56} / _{14.2}

P = 3.94

Therefore, theÂ **load appliedÂ **isÂ **3.94.**

**Calculating the Length of Indenter Tip when the Knoop Hardness Number and the Load Applied are Given**

l = âˆš^{14.2P} / _{HK}

Where:

l = Length of Indenter Tip

HK = Knoop Hardness Number

P = Load Applied

Let’s solve an example;

Find the length of indenter tip when the knoop hardness number is 8 and the load applied is 6.

This implies that;

HK = Knoop Hardness Number = 8

P = Load Applied = 6

l = âˆš^{14.2P} / _{HK}

l = âˆš^{14.2 (6)} / _{8}

So, l = âˆš^{85.2} / _{8}

l = âˆš10.65

l = 3.26

Therefore, theÂ **length of indenter tip **isÂ **3.26.**

Read more:Â How to Calculate and Solve for Brinell Hardness Number | Mechanical Properties

**How to Calculate Knoop Hardness Number With Nickzom Calculator**

Nickzom Calculator â€“Â **The Calculator Encyclopedia** is capable of calculating the knoop hardness number.

To get the answer and workings of the knoop hardness number using the **Nickzom Calculator â€“ The Calculator Encyclopedia.Â **First, you need to obtain the app.

You can get this app via any of these means:

**Web**Â â€“Â https://www.nickzom.org/calculator-plus

To get access to theÂ **professionalÂ **version via web, you need toÂ **register**Â andÂ **subscribeÂ **to have utter access to all functionalities.

You can also try theÂ **demoÂ **version viaÂ https://www.nickzom.org/calculator

**Android (Paid)**Â â€“Â https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator

**Android (Free)**Â â€“Â https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator

**Apple (Paid)**Â â€“Â https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8

Once, you have obtained the calculator encyclopedia app, proceed to theÂ **Calculator Map,Â **then click onÂ **Materials and MetallurgicalÂ **underÂ **Engineering****.**

Now, Click onÂ **Mechanical Properties****Â **underÂ **Materials and Metallurgical**

Now, Click on **Knoop Hardness Number****Â **underÂ **Mechanical Properties**

The screenshot below displays the page or activity to enter your values, to get the answer for the knoop hardness number according to the respective parameter which is the **Load Applied (P)Â **andÂ **Length of Indenter Tip (l).**

Now, enter the values appropriately and accordingly for the parameters as required by the **Load Applied (P)** is **21 **and **Length of Indenter Tip (l)** is **3**.

Finally, Click on Calculate

As you can see fromÂ the screenshot above,Â **Nickzom Calculator**â€“ The Calculator Encyclopedia solves for the knoop hardness number and presents the formula, workings and steps too.