## What Is the x-Intercept?

The x-intercept is the x-ordinate of a point on a straight line, where the line intersects the X-axis. If a straight line intersects the X-axis at (2,0), the x-intercept will be 2.

## How to Find the X Intercept for Linear Data in Excel

Consider a linear equation (**y = 3x – 7**). To find the value of **X** when **y = 0:**

- Select
**C12**>> use the following formula >> press**Enter.**

`=INTERCEPT(B6:B10,C6:C10)`

- Plot a
**Scatter with Smooth Lines and Markers**chart.

**Important Notes**

- The
**INTERCEPT**function finds the point at which a line intersects the y-axis. It uses known x-values and known y-values.

- The
**INTERCEPT**function considers the intersection at the y-axis, which means it calculates the y-intercept. - When you calculate the x-intercept with the
**INTERCEPT**function, your y-values will be**INTERCEPT**Â x values and your x-values will be**INTERCEPT**Â y-values.

## How to Find the x-Intercept in Excel – 5 Methods

The dataset showcases **monthly Covid cases** (set as Y-values) and **monthly use of masks** (set as X-values).

You want to know *what is the percentage of people using masks when the number of covid cases becomes zero*.

**Method 1 – Using the INTERCEPT Function to Find the x-Intercept**

Use the **INTERCEPT function**.

**Â Steps:**

- Use the following formula in
**C18**to find the x-intercept.

`=INTERCEPT(C5:C16,D5:D16)`

**Your x-values**=**C5:C16** â‡’ **y-values in the formula**.

**Your y-values**=**D5:D16** â‡’ **x-values in the formula**.

The **x-intercept = 90.16%** (*after applying the percentage format*).

**Â Interpretation of the x-Intercept:**

- The y value (covid cases) is set to zero.
- When the use of masks is 90.16%, covid cases will be zero.
- Or, when the covid cases tend to zero, the use of masks is still 90.16%.

### Method 2 – Using the FORECAST.LINEAR Function to Find the X-Intercept

**Steps:**

- Select
**D19**>> enter the following formula >> click**OK.**

`=FORECAST.LINEAR(D18,C5:C16,D5:D16)`

**Notes**

When calculating X Intercept using the **FORECAST.LINEAR** function, you must switch between the **known_ys** and **know_xs** values: People Using Masks (X) as known_ys and Covid Cases (Y) as know_xs.

**Method 3 – Using the Trendline Equation Feature of Excel Graphs**

**Steps:**

- Go to the
**Insert tab**and click**Scatter**. - Select the first icon.

- A blank graph canvas will be displayed.
- Click the
**Chart Area****canvas**and right-click. - Click
**Select Data…****option**.

- In the
**Select Data Source**window, click**Add**.

- In
**Edit Series**, name the series (**Calculate x-Intercept**).

- Choose the
**X values**.*(Excelâ€™s X values are equivalent to Y values here.)*

- Choose the
**Y values**. - Click
**OK**.

- The
**Calculate x-Intercept**series is displayed in the**Select Data Source**window and automatically selected. - Click
**OK**.

- Click the
**Chart Elements button**(the**+ sign**Â in the image below). - Uncheck
**Gridlines**. - Select
**Trendline**and click the**angle icon**(**âŒª**). - Select
**More Options**.

- In
**Format Trendline**, click the**3rd icon**(**Trendline Options**). - Select
**Linear**. - Check ‘
**Display****Equation****on the chart’**.

- Go back to the graph.
- An equation is displayed in the chart area:

**y=-0.0001x+0.9016**

- This is the output: the x-intercept is
**0.9016**(*90.16%, when formatted as a percentage*).

**Read More:** **How to Set Intercept Trendline in Excel**

**Method 4 – Using the LINEST Function to Find the x-Intercept**

Use the **LINEST function** in a combination of the **SLOPE** and the **INTERCEPT** functions.

**Steps:**

- Use the formula inÂ
**C19**:

`=LINEST(C5:C16,D5:D16)`

- Press
**ENTER**.

- The intercept is displayed in
**C20**(*and a slope in*).**C19**

**Read More:** **How to Find Intercept of Two Lines in Excel**

**Method 5 – Using the Data Analysis ToolPak**

**Â Steps:**

- To enable the
**Data Analysis ToolPak**, press**ALT+F+T**and go to the**Excel****Options**window. - Select
**Add-ins**and choose**Excel Add-ins**in**Manage**. - Click
**Go**.

- In
**Add-ins**, check**Analysis ToolPak**. - Click
**OK**.

- The feature is displayed on the
**ribbon**. - Go to the
**Data****tab**and click**Data Analysis**in**Analysis**.

- In
**Data Analysis**, select**Regression**and click**OK**.

- In the
**Regression****window**, Enter the**Input Y Range**(remember you have to select your X-values here). - Enter the
**Input****X****Range**. - Click
**OK**.

- In the
**Regression****window**, select a location to place the**Output****Range**(here*,*).**F4** - Click
**OK**.

- The regression summary will be generated by ToolPak. You will see the x-intercept and other statistic data.

**Read More:** **How to Find Y Intercept in Excel**

**Download Practice Workbook**

Download the following workbook.

**<< Go Back toÂ Excel INTERCEPT Function | Excel Functions | Learn Excel**

Hey, these 4 methods to determine an x-intercept for a data set are wrong. You have to determine the x incept for a given line by solving the equation of a line for x and setting y=0. None of these methods provide and even close to accurate value for a data sets linear regression line’s x-intercept. READER BEWARE.

Hello

Dr TimberI went through this article and did not find any technical issues. In my view, you should reconsider what you have said.

This article is about finding an

X intercept. To demonstrate this point, this context considers a practical dataset where the percentage of people still using masks is calculated when the number ofCovid CasesbecomesZero. I think you expected the calculation to findX InterceptforY = 0. That’s what is calculated in those methods. When the writer introduced us to the dataset, it was explicitly mentioned.Anyway, I am introducing another method that may overcome your confusion. I have calculated the percentage of people who still use masks when the number of Covid Cases becomes Zero. I am using

FORECAST.LINEAR Functionto predict the percentage. And I get the same result shown in this article.Excel Formula:The data considered in this article is not Linear. That’s why you get confused. However, these methods must be able to find an X intercept for any Linear data.

Stay safe. And good luck!

Regards

Lutfor Rahman Shimanto