An Excel trendline represents the primary pattern or direction of the data on an Excel chart. The trendline can be a straight or curved line depending on the trendline type. A **trendline equation** is an equation for the trendline on an Excel curve. The main focus of this article is to explain how to use** trendline equation** in Excel.

To explain this article I have taken the following dataset that contains Years and Sales.

I have also taken a column chart of the dataset to show the use of the **trendline equation** in Excel.

**Table of Contents**Expand

## 1. Adding Trendline Equation in Excel

In this first example, I will explain how to add a **trendline equation **in Excel.

Letâ€™s see the steps.

**Steps:**

- Firstly, select the chart in which you want to add the trendline.
- Secondly, go to
**Chart Elements**. - Thirdly, select
**Trendline**.

Now, you will see a **trendline **has been added to your chart.

After that, you can change the color of the **trendline** to make it more visible.

- Firstly, Right-click on the
**trendline**. - Secondly, select
**Format Trendline**.

Here, you will see that the **Format Timeline **option will appear on the right side of the screen.

- Firstly, go to
**Fill & Line**. - Secondly, select
**Color**.

Now, you will see a list of colors will appear.

- Next, select the color you want. Here, I selected
**Red**.

After that, you will see that you have got your desired **trendline**.

Here, you can also change the **trendline** type.

- Firstly, Right-click on the trendline.
- Secondly, select
**Format Trendline**.

Here, you will see that the **Format Timeline **option will appear on the right side of the screen.

- Firstly, go to the
**Trendline Options**. - Secondly, select the
**trendline**type you want. Here, I kept it**Linear**which was set by default.Â But you can select any other option you want.

Now, I will add the **trendline equation**.

- Firstly, Right-click on the trendline.
- Secondly, select
**Format Trendline**.

Here, you will see that the **Format Timeline **option will appear on the right side of the screen.

- Firstly, go to the
**Trendline Options**. - Secondly, select
**Display Equation on chart**.

Finally, you will see the **trendline equation **on the chart.

**Read More: **How to Add Trendline Equation in Excel

## Â 2. Using Trendline Equation in Excel to Forecast Data

To explain this example, I have taken a dataset that contains the **Temperature (K)** and** Volume (Liter) **of a gas. I also have a column chart of the dataset with a **Linear Trendline **and **trendline equation**. Here, I will show you how to use** trendline equation** in Excel to forecast data.

Letâ€™s see the steps.

**Steps:**

- Firstly, select the cell where you want to forecast the data. Here, I selected cell
**C10**. - Secondly, in cell
**C10**write the following formula.

`=0.114*B10-2.8`

Here, In this formula, I used the trendline equation from the chart. I took **B10 **as **X**. Now, the formula will return the **Y **value.

- After that, press
**ENTER**to get the**Y**

- Next, drag the
**Fill Handle**to copy the formula.

Now, you will see that you have got your forecasted data using the** trendline equation** in Excel.

## 3. Using Trendline Equation in Excel to Get Values for Any Given X

For this example, I have taken a dataset that contains the **Temperature (K)** and** Volume (Liter) **of a gas. I also have a column chart of the dataset with a **Linear Trendline **and **trendline equation**. Here, I will explain how to use** trendline equation** in Excel to get values for any given **X**.

Letâ€™s see the steps.

**Steps:**

- Firstly, select the cell where you want to get the
**Y**value for a given**X**. Here, I selected cell**C12**. - Secondly, in cell
**C12**write the following formula.

`=0.114*B12-0.8`

Here, In this formula, I used the **trendline equation** from the chart. I took **B12 **as **X**. Now, the formula will return the **Y **value.

- After that, press
**ENTER**to get the**Y**

- Now, drag the
**Fill Handle**to copy the formula.

Here, you will see that you have got your **Y **values for any given **X **using the** trendline equation** in Excel.

**Read More: **How to Find Unknown Value on Excel Graph

## 4. Inserting Linear Trendline Equation to Find Slope and Intercept

To explain this example, I have taken a dataset that contains **Years **and **Sales**. I also have a **column chart **of the dataset with a **linear trendline** and **trendline equation**. Here, I will use the **linear trendline equation **to find the **Slope **and **Intercept**. I will also use functions to find the **Slope **and **Intercept** for the dataset to see if it matches the **trendline equation**.

In the following Image, you can see that from the **linear trendline equation **I have got the **Slope** and **Intercept**. Now, I will use functions to find the **Slope **and **Intercept** for the dataset.

Letâ€™s see the steps.

**Steps:**

- Firstly, select the cell where you want to calculate the
**Slope**. Here, I selected cell**G5**. - Secondly, in cell
**G5**write the following formula.

`=SLOPE(C5:C9,B5:B9)`

Here, in the **SLOPEÂ ** function, I selected **C5:C9 **as **known_ys **and **B5:B9 **as **known_xs**. This function will return the value of the **Slope **for the dataset.

- Finally, press
**ENTER**to get the value of the**Slope**.

Now, I will calculate the **Intercept**.

- Firstly, select the cell where you want to calculate the
**Intercept**. Here, I selected cell**G6**. - Secondly, in cell
**G6**write the following formula.

`=INTERCEPT(C5:C9,B5:B9)`

Here, in the **INTERCEPT** function, I selected **C5:C9 **as **known_ys **and **B5:B9 **as **known_xs**. This function will return the value of the **Intercept **for the dataset.

- Finally, press
**ENTER**to get the value of the**Intercept**.

Now, you will see that the values of the **Slope **and **Intercept **from the equation match the values that we got using functions. This means the values from the** trendline equation** are correct.

**Read More: **How to Find Slope of Trendline in Excel

## 5. Using Exponential Trendline Equation in Excel to Find the Coefficients

To explain this example, I have taken a dataset that contains **Years **and **Sales**. I also have a **column chart **of the dataset with an **exponential trendline** and **trendline equation**. Here, I will use the **exponential trendline equation **to find **Coefficient a **and **Coefficient b**. I will also use functions to find **Coefficient a **and **Coefficient b** for the dataset to see if they match the **trendline equation**.

In the following Image, you can see that from the **exponential trendline equation **I have got **Coefficient a **and **Coefficient b**. Now, I will use functions to find **Coefficient a **and **Coefficient b** for the dataset.

Letâ€™s see the steps.

**Steps:**

- Firstly, select the cell where you want to calculate the
**Coefficient a**. Here, I selected cell**G5**. - Secondly, in cell
**G5**write the following formula.

`=EXP(INDEX(LINEST(LN(C5:C9),B5:B9),1,2))`

**Formula Breakdown**

- Here, in the
**EXP**function, I used the**INDEX**function as a**number**that will return the value from a range. - Now, in the
**INDEX**function, I used the**LINEST**function as array 1 as**row_num**, and**2**as**column_num**. - Next, In
**the LINEST function**, I selected**LN(C5:C9)**as**known_ys**Â the**LN**function will return the natural logarithm of the given range, and**B5:B9**as**known_xs**. - Finally, the
**EXP**function will return the result of the constant**e**raised to the power of the**number**which will be our**coefficient a**.

- Thirdly, press
**ENTER**to get the**coefficient a**.

Now, I will calculate **Coefficient b**.

- Firstly, select the cell where you want to calculate the
**Coefficient b**. Here, I selected cell**G6**. - Secondly, in cell
**G6**write the following formula.

`=INDEX(LINEST(LN(C5:C9),B5:B9),1)`

**Formula Breakdown**

- Here, in the
**INDEX**function, I used a**LINEST**function as**array**and**1**as**row_num**. - Next, In the
**LINEST**function, I selected**LN(C5:C9)**as**known_ys**which will return the natural logarithm of the given range, and**B5:B9**as**known_xs**. - Finally, the
**INDEX**function will return the value from the**table**which will be**Coefficient b**.

- Thirdly, press
**ENTER**to get the**Coefficient b**.

Now, you will see that the values of **Coefficient a **and **Coefficient b **from the equation match the values that we got using functions. This means the values from the** trendline equation** are correct.

## 6. Applying Logarithmic Trendline Equation in Excel

To explain this example, I have taken a dataset that contains **Years **and **Sales**. I also have a **column chart **of the dataset with a **logarithmic trendline** and **trendline equation**. Here, I will use the **logarithmic trendline equation **to find **Constant a **and **Constant b**. I will also use functions to find **Constant a **and **Constant b** for the dataset to see if they match the **trendline equation**.

In the following Image, you can see that from the **logarithmic trendline equation **I have got **Constant a **and **Constant b**. Now, I will use functions to find **Constant a **and **Constant b** for the dataset.

Letâ€™s see the steps.

**Steps:**

- Firstly, select the cell where you want to calculate the
**Constant a**. Here, I selected cell**G5**. - Secondly, in cell
**G5**write the following formula.

`=INDEX(LINEST(C5:C9,LN(B5:B9)),1)`

**Formula Breakdown**

- Here, in the
**INDEX**function, I used a**LINEST**function as**array**and**1**as**row_num**. - Next, In the
**LINEST**function, I selected**C5:C9**as**known_ys**, and**LN(B5:B9)**as**known_xs**which will return the natural logarithm of the given range. - Finally, the
**INDEX**function will return the value from the**table**which will be**Constant a**.

- Thirdly, press
**ENTER**to get the**Constant a**.

Now, I will calculate **Constant b**.

- Firstly, select the cell where you want to calculate the
**Constant b**. Here, I selected cell**G6**. - Secondly, in cell
**G6**write the following formula.

`=INDEX(LINEST(C5:C9,LN(B5:B9)),1,2)`

**Formula Breakdown**

- Here, in the
**INDEX**function, I used a**LINEST**function as**array**and**1**as**row_num**and**2**as**column_num**. - Next, In the
**LINEST**function, I selected**C5:C9**as**known_ys**, and**LN(B5:B9)**as**known_xs**which will return the natural logarithm of the given range. - Finally, the
**INDEX**function will return the value from the**table**which will be**Constant b**.

- Thirdly, press
**ENTER**to get the**Constant b**.

Now, you will see that the values of **Constant a **and **Constant b **from the equation match the values that we got using functions. This means the values from the** trendline equation** are correct.

## 7. Using Polynomial Trendline Equation in Excel

To explain this example, I have taken a dataset that contains **Years **and **Sales**. I also have a **column chart **of the dataset with a **Polynomial trendline** and **trendline equation**. Here, I will use the **Polynomial trendline equation **to find **Coefficient b1**, **Coefficient b2**, and **Constant a**. I will also use functions to find **Coefficient b1**, **Coefficient b2**, and **Constant a** for the dataset to see if they match the **trendline equation**.

In the following Image, you can see that from the **Polynomial trendline equation **I have got **Coefficient b1**, **Coefficient b2**, and **Constant a**. Now, I will use functions to find **Coefficient b1**, **Coefficient b2**, and **Constant a** for the dataset.

Letâ€™s see the steps.

**Steps:**

- Firstly, select the cell where you want to calculate the
**Coefficient b1**. Here, I selected cell**G5**. - Secondly, in cell
**G5**write the following formula.

`=INDEX(LINEST(C5:C9,B5:B9^{1,2}),1)`

**Formula Breakdown**

- Here, in the
**INDEX**function, I used a**LINEST**function as**array**and**1**as**row_num**. - Next, In the
**LINEST**function, I selected**C5:C9**as**known_ys**, and**B5:B9^{1,2}**as**known_xs**which will raise the range**B5:B9**to the**power**of**{1,2}**. - Finally, the
**INDEX**function will return the value from the**table**which will be**Coefficient b1**.

- Thirdly, press
**ENTER**to get**Coefficient b1**.

Now, I will calculate **Coefficient b2**.

- Firstly, select the cell where you want to calculate the
**Coefficient b2**. Here, I selected cell**G6**. - Secondly, in cell
**G6**write the following formula.

`=INDEX(LINEST(C5:C9,B5:B9^{1,2}),1,2)`

**Formula Breakdown**

- Here, in the
**INDEX**function, I used a**LINEST**function as**array**,**1**as**row_num**and,**2**as**column_num**. - Next, In the
**LINEST**function, I selected**C5:C9**as**known_ys**, and**B5:B9^{1,2}**as**known_xs**which will raise the range**B5:B9**to the**power**of**{1,2}**. - Finally, the
**INDEX**function will return the value from the**table**which will be**Coefficient b2**.

- Thirdly, press
**ENTER**to get**Coefficient b2**.

Here, I will calculate **Constant a**.

- Firstly, select the cell where you want to calculate the
**Constant a**. Here, I selected cell**G7**. - Secondly, in cell
**G7**write the following formula.

`=INDEX(LINEST(C5:C9,B5:B9^{1,2}),1,3)`

**Formula Breakdown**

- Here, in the
**INDEX**function, I used a**LINEST**function as**array**,**1**as**row_num**and,**3**as**column_num**. - Next, In the
**LINEST**function, I selected**C5:C9**as**known_ys**, and**B5:B9^{1,2}**as**known_xs**which will raise the range**B5:B9**to the**power**of**{1,2}**. - Finally, the
**INDEX**function will return the value from the**table**which will be**Constant a**.

- Thirdly, press
**ENTER**to get**Constant a**.

Now, you will see that the values of **Coefficient b1**, **Coefficient b2**, and **Constant a **from the equation match the values that we got using functions. This means the values from the** trendline equation** are correct.

**Read More: **How to Find Slope of Polynomial Trendline in Excel

## 8. Using Power Trendline Equation in Excel

To explain this example, I have taken a dataset that contains **Years **and **Sales**. I also have a **column chart **of the dataset with a **power trendline** and **trendline equation**. Here, I will use the **power trendline equation **to find **Constant a **and **Constant b**. I will also use functions to find **Constant a **and **Constant b** for the dataset to see if they match the **trendline equation**.

In the following Image, you can see that from the **power trendline equation **I have got **Constant a **and **Constant b**. Now, I will use functions to find **Constant a **and **Constant b** for the dataset.

Letâ€™s see the steps.

**Steps:**

- Firstly, select the cell where you want to calculate the
**Constant a**. Here, I selected cell**G5**. - Secondly, in cell
**G5**write the following formula.

`=EXP(INDEX(LINEST(LN(C5:C9),LN(B5:B9), ,),1,2))`

**Formula Breakdown**

- Here, in the
**EXP**function, I used an**INDEX**function as a**number**that will return the value from a range. - Now, in the
**INDEX**function, I used a**LINEST**function as an**array**and**1**as**row_num**, and**2**as**column_num**. - Next, In the
**LINEST**function, I selected**LN(C5:C9)**as**known_ys**which will return the natural logarithm of the given range, and**LN(B5:B9)**as**known_xs**which will return the natural logarithm of the given range, and left**const**and**stats** - Finally, the
**EXP**function will return the result of the constant**e**raised to the power of the**number**which will be our**Constant a**.

- Thirdly, press
**ENTER**to get the**Constant a**.

Now, I will calculate **Constant b**.

- Firstly, select the cell where you want to calculate the
**Constant a**. Here, I selected cell**G6**. - Secondly, in cell
**G6**write the following formula.

`=INDEX(LINEST(LN(C5:C9),LN(B5:B9),,),1)`

**Formula Breakdown**

- Here, in the
**INDEX**function, I used a**LINEST**function as an**array**and**1**as**row_num**. - Next, In the
**LINEST**function, I selected**LN(C5:C9)**as**known_ys**which will return the natural logarithm of the given range, and**LN(B5:B9)**as**known_xs**which will also return the natural logarithm of the given range, and left**const**and**stats** - Finally, the
**INDEX**function will return the value from the**table**which will be**Constant b**.

- Thirdly, press
**ENTER**to get the**Constant b**.

Now, you will see that the values of **Constant a **and **Constant b **from the equation match the values that we got using functions. This means the values from the** trendline equation** are correct.

**Practice Section**

Here, I have provided a practice sheet for you to practice how to use** trendline equation** in Excel.

**Download Practice workbook**

**Conclusion**

To conclude, in this article, I tried to show different examples of how to use** trendline equation** in Excel. If you have any questions feel free to let me know in the comment section below.

## Related Articles

- How to Find the Equation of a Line in Excel
- How to Find the Equation of a Trendline in Excel
- How to Show Equation in Excel Graph
- How to Get Y Equation on Excel Graph
- How to Create Equation from Data Points in Excel
- How to Find Intersection of Two Trend Lines in Excel

**<< Go Back To Trendline Equation Excel | Trendline in ExcelÂ |Â Excel ChartsÂ |Â Learn Excel**