**Microsoft Excel** allows us to estimate different types of data and carry out monetary, mathematical, and statistical computations. **Excel** is a great tool for interpolation as it essentially performs as a large visual calculator. **Interpolation** is the method of calculating unknown points within an existing known data set. When we try to find unknown values of a function between two known values, interpolation is used. **Excel** allows us to perform interpolation, both linear and exponential, in an easier way. In this article, I will try to explain a couple of ways to calculate **exponential interpolation in Excel**.

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## 4 Easy Ways of Performing Exponential Interpolation in Excel

In the case of a real-world dataset where the values are exponential, we can use different **Excel Functions** to perform the interpolation. In this article we are going to use ** Excel 365 version**, you can use any other version as well. Here, we will discuss

**4**effective ways of

**exponential interpolation**. We will use the following exponential dataset to show the ways of interpolation in

**Excel**.

In this dataset, there are a total of

**2**columns of

**Sales Year & Sales**and

**12**rows. Here the

**Sales Year**column denotes

**X coordinate**values and the

**Sales**column denotes

**Y coordinate**values. As we can see these values are generating an exponential graph for which we will perform our interpolation.

### 1. Using GROWTH Function to Perform Exponential Interpolation

**The GROWTH function** in Excel allows us to interpolate data when the data set has exponential growth. It uses exponential regression to predict a value. In our dataset, the values of the **X coordinate** and **Y coordinate** have a linear relation between them.

**Steps:**

- Select cell
**C16**and enter the sales year of which we want to know the**sales value**. Let it be**2015**.

- Select cell
**C17**and then type the following formula.

`=GROWTH(C5:C15,B5:B15,C16)`

Here, in the **first argument **enter the range of cells of known **y-values,** in the **second argument**, the range of cells of known **x-values,** and in the **last argument** enter the new **x-value** for which you want to know the **y-value**. In this dataset, **X coordinate **values denote the **Sales Year **column and** Y coordinate** values denote the **Sales** column.

- Press
**ENTER Key**and the result will be shown in cell**C17**.

Here, we got the **Sales** value for the year **2015**.

### 2. Adding Trendline for Exponential Interpolation in Excel

In Excel, we can utilize **the Trendline feature** when the dataset is **non-linear**. **The Exponential Trendline** is an angled line that illustrates an increasing increase or decrease in data values. However, we have to keep in mind that we cannot create **an Exponential Trendline** for the dataset that have **negative values or zeros**.

**Steps:**

- Select cell
**C16**and enter the sales year for which we want to know the sales value using**the Trendline feature**. Let it be**2015**.

- Click on the chart and then click on the
**plus**symbol which is**CHART ELEMENTS**. - Click on the
**check mark**beside**Trendline**and we will get the dotted curve line in our chart.

- After that put your cursor on the
**Trendline**and**Right-click**on your mouse. - Click
**Format Trendline**.

- After clicking
**Format Trendline**, you will get the**Format Trendline**dialog box. - Select
**E**and scroll down.__x__ponential

- Click on the
**check mark**beside**Display**.__E__quation on chart - Click
**Close**.

- We will get our desired equation that we can use in
**C17**.

The equation is like this below.

**y = 7E-36e**

^{0.0423x}- Select cell
**C17**and then type the following equation.

**=7*POWER(10,-36)*EXP(0.0423*2015)**

**Formula Breakdown**

**POWER(10,-36) →****The POWER function**will return the result of the number**10**raised to the power**-36**. Here, 10 is the number, and -36 is the power value.**Output → 1E-36**

**7*POWER(10,-36) →**becomes**7*1E-36****Output → 7E-36**

**EXP(0.0423*2015)**→**The EXP function**will return**e**raised to the power of number 2015.**Output → 03961615076379E+37**

**7*POWER(10,-36)*EXP(0.0423*2015) →**becomes**7*7E-36*1.03961615076379E+37****Output → 72.77313055**

- Press
**ENTER Key**and the result will be shown in cell**C17**.

Here, we got the **Sales** value of **2015**.

### 3. Applying FORECAST Function for Exponential Interpolation in Excel

**The FORECAST function** in **Excel** is widely used to predict performance by analyzing a set of real-world data points. This is used to determine or estimate a future value based on previous values; the predicted value is a **y-value** for a given **x-value**.

It is to notify you that to make room for the new **Forecasting functions**, **the FORECAST function** in Excel **2016** was replaced with **the FORECAST.LINEAR function**. If you are going to use a version of Excel older than **2016**, you can only use **the FORECAST function** since Microsoft Excel added **FORECAST.LINEAR** in the **2016 **version.

**Steps:**

- Select cell
**C16**and**ENTER**the sales year of which we want to know the sales value using**the FORECAST function**. Let it be**2015**.

- Select cell
**C17**and then type the following formula.

**=FORECAST(C16,C5:C15,B5:B15)**

Here, in the **first argument** enter the **x-value** for which you want to know the **y-value**, in the **second argument **enter the range of cells of known **y-values,** and in the **last argument**, the range of cells of known **x-values**. In this dataset, **X coordinate **values denote the **Sales Year **column and** Y coordinate** values denote the **Sales** column.

- Press
**ENTER Key**and the result of**Sales**will be shown in cell**C17**.

Here, in cell **C17** we got the sales value of **2015**.

**The FORECAST function** and** FORECAST.LINEAR function** are effectively the same. So you can utilize that as well. The result will be the same as before.

For that, the following formula will be generated in cell **C17** as

**=FORECAST.LINEAR(C16,C5:C15, B5:B15)**

### 4. Utilizing TREND Function for Exponential Interpolation in Excel

**The TREND Function** is an **Excel Statistical function** that estimates an unknown value based on linear regression. Here, for this dataset, you can use **the TREND Function **of Excel.

**Steps:**

- Select cell
**C16**and enter the sales year of which you want to know the sales value using**the TREND function**. Let it be**2015**.

- Select cell
**C17**and then type the following formula.

**=TREND(C5:C15,B5:B15,C16)**

Here, in the **first argument **enter the range of cells of known **y-values**, in the **second argument**, the range of cells of known **x-values,** and in the **last argument** enters the **x-value** for which you want to know the **y-value**. As you already know that in the dataset **X coordinate **values denote the **Sales Year **column and** Y coordinate** values denote the **Sales** column.

- Press
**ENTER Key**and the result will be shown in cell**C17**.

Here, in cell **C17** we got the sales value of **2015**.

## Practice Section

You can use the following dataset to practice by yourself. Hope it will help you to learn more.

## Conclusion

This article will help you to understand how to use different functions to perform **exponential interpolation in Excel**. You can use these **4 effective ways** to calculate interpolation when you have a real-world dataset. I hope you have found this article interesting as well as effective. If you face any difficulties understanding any topic please leave a comment in the comment section below and give us your feedback. You can also visit **ExcelDemy** to find many more articles like this one.