The image above represents horizontal stress.

To compute for horizontal stress, two essential parameters are needed and these parameters are **Poisson’s ratio (v) **and **vertical stress (σ _{v}).**

The formula for calculating the horizontal stress:

σ_{H} = ^{vσv} / _{1 – v}

Where;

σ_{H} = Horizontal Stress

v = Poisson’s Ratio

σ_{v} = Vertical Stress

Let’s solve an example;

Find the horizontal stress when the Poisson’s ratio is 24 and the vertical stress is 28.

This implies that;

v = Poisson’s Ratio = 24

σ_{v} = Vertical Stress = 28

σ_{H} = ^{vσv} / _{1 – v}

σ_{H} = ^{24(28)} / _{(1 – 24)}

σ_{H} = 672 / _{-23}

σ_{H} = -29.217

Therefore, the **horizontal stress **is **29.217.**

**Calculating the Poisson’s Ratio when the Horizontal Stress and Vertical stress is Given.**

v = ^{σH} / _{σv + σH}

Where;

v = Poisson’s Ratio

σ_{H} = Horizontal Stress

σ_{v} = Vertical Stress

Let’s solve an example;

Find the Poisson’s ratio when the horizontal stress is 12 and the vertical stress is 16.

This implies that;

σ_{H} = Horizontal Stress = 12

σ_{v} = Vertical Stress = 16

v = ^{σH} / _{σv + σH}

v = ^{12} / _{16 + 12}

v = ^{12} / _{28}

v = ^{12} / _{28}

v = 0.428

Therefore, the **Poisson’s ratio **is **0.428.**

**Calculating the Vertical Stress when the Horizontal Stress and the Poisson’s Ratio is Given.**

σ_{v} = ^{σH (1 – v)} / _{v}

Where;

σ_{v} = vertical stress

σ_{H} = Horizontal Stress

v = Poisson’s ratio

Let’s solve an example;

Find the vertical stress when the horizontal stress is 14 and the Poisson’s ratio is 8.

This implies that;

σ_{H} = Horizontal Stress = 14

v = Poisson’s ratio = 8

σ_{v} = ^{σH (1 – v)} / _{v}

σ_{v} = ^{14 (1 – 8)} / _{8}

σ_{v} = ^{14 (- 7)} / _{8}

σ_{v} = ^{– 98} / _{8}

σ_{v} = – 12.25

Therefore, the **vertical stress **is **– 12.25.**

Nickzom Calculator – **The Calculator Encyclopedia** is capable of calculating the horizontal stress.

To get the answer and workings of the horizontal stress using the **Nickzom Calculator – The Calculator Encyclopedia. **First, you need to obtain the app.

You can get this app via any of these means:

**Web** – https://www.nickzom.org/calculator-plus

To get access to the **professional **version via web, you need to **register** and **subscribe **for** NGN 1,500 **per** annum** to have utter access to all functionalities.

You can also try the **demo **version via https://www.nickzom.org/calculator

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

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

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

Once, you have obtained the calculator encyclopedia app, proceed to the **Calculator Map, **then click on **Geology**** **under **Add-on.**

Now, Click on **Rock Mechanics**** **under **Geology**

Now, Click on **Horizont****al ****Stress **under **Rock Mechanics**

The screenshot below displays the page or activity to enter your values, to get the answer for the lateral strain according to the respective parameters which are the **Poisson ratio (v) **and **vertical stress (σ _{v}).**

Now, enter the values appropriately and accordingly for the parameters as required by the **Poisson ratio (v) **is **24 **and **vertical stress (σ _{v})** is

**28**

**.**

Finally, Click on Calculate

As you can see from the screenshot above, **Nickzom Calculator**– The Calculator Encyclopedia solves for the horizontal stress and presents the formula, workings and steps too.