## What Is Interpolate In Excel?

Interpolate in Excel or Interpolationhelps users to evaluate or forecast an unknown value that lies between two known data points in a dataset. The graphical representation is related to the data points such as noise level, rainfall, elevation, etc.

The **Interpolate Excel **is an inbuilt **Statistical** function with the name as **Forecast, **so we can insert the formula from the “**Function Library**” or enter it directly in the worksheet.

For example, the image below depicts the values, and we will calculate using the **Interpolate formula , **i.e., the

**Forecast**formula.

Select cell **C2**, enter the formula ** =FORECAST(B1,B3:B5,A3:A5), **and press “

**Enter**”.

The result is ‘**5**’, as shown above using the **Linear** graph.

##### Table of contents

###### Key Takeaways

**Interpolate in Excel**is the process used to predict or derive values between the given values.- We can calculate the Interpolation for a dataset using the
**Forecast function**with the same size cell ranges for the x and y values. - The different types of Interpolates are
**Piecewise Constant Interpolation, Linear Interpolation, Polynomial Interpolation, Spline Interpolation,**and**Mimetic Interpolation**. - Linear Interpolation is used to predict values for rainfall, geographical data points, etc.
- We can calculate the Interpolate mathematically using the formula,
**y = y1 + (x – x1)****⨯****(y2 – y1) / (x2 – x1).**

### Interpolate Excel Formula

**Linear Interpolation – **This method is quick and easy to use, also known as Lerp. To perform the Linear Interpolate calculations, we use the **FORECAST Excel formula**.

The syntax of the **FORECAST Excel formula** is,

The three mandatory arguments of the **FORECAST Excel formula** are,

It is the predicted value.*x:*: It is a dependent value in the dataset.*known_ys*It is an independent value in the dataset.*known_xs:*

### How To Interpolate in Excel?

We can find **Interpolate in Excel **using 2 ways, namely,

**Access from the Excel ribbon.****Enter in the worksheet manually.**

#### Method #1 – Access from the Excel ribbon

Choose an empty cell → select the **“Formulas” **tab → go to the “**Function Library**” group → click the **“More Functions…”** option drop-down → select the **“Statistical” **option right arrow → select the **“FORECAST.LINEAR”** option, as shown below.

The **“Function Arguments” **window appears. Enter the arguments in the **“X”, “ Known_ys”, **and

**“**fields, and click “

*Known_xs*”**OK**”

**.**

#### Method #2 – Enter in the worksheet manually

- Select an empty cell for the output.
- Type
**=****FORECAST****(**in the selected cell. [Alternatively, type**=F**or**=FORE**and double-click the**FORECAST.LINEAR****Interpolate****function**from the list of suggestions shown by Excel. - Enter the arguments as cell values or cell references and close the brackets.
- Press the “
**Enter**” key.

Let us take a basic example to learn this function.

We will calculate the interpolation using the **FORECAST function **for the value of x & y.

In the table, the data is,

- Cell B1 contains the x values.
- Column A contains the
**known_xs**values. - Column B contains the
**known_ys**values.

The steps to calculate the **Interpolation** in excel using the **FORECAST formula **are,

**Select cell C2, and enter the formula =FORECAST.LINEAR(B1, i.e., x argument value.****The entered value of the known_ys argument in cells “B3:B10”. The formula now is =FORECAST.LINEAR(B1,B3:B10****Enter the value of the known_xs argument as “A3:A10”, and close the brackets. The complete formula is =FORECAST.LINEAR(B1,B3:B10,A3:A10).****Press the “Enter” key. The calculated result is “4”, as shown below, along with a graph.**

### Examples

We will consider some advanced scenarios for **Interpolate in Excel** using the **Forecast formula.**

#### Example #1

We will calculate the **Interpolate **using the **FORECAST function **for the value of time and distance in columns.

In the table, the data is,

- Cell B1 contains the x values.
- Column A contains the
**known_xs**values. - Column B contains the
**known_ys**values.

The procedure to calculate the **Interpolate in Excel** using the **FORECAST formula **is,

Select cell **C2**, enter the formula ** =FORECAST.LINEAR(B1,B3:B6,A3:A6),** and press “

**Enter**”.

The calculated result is “**1.097460087**”, as shown above along with the graph.

#### Example #2

We will calculate the **Interpolate** using the **FORECAST function** for thevalue of monthly sales & quantity of ABC company.

In the table, the data is,

- Cell B1 contains the x values.
- Column A contains the
**known_xs**values. - Column B contains the
**known_ys**values.

The procedure to calculate the **Interpolate in Excel** using the **FORECAST formula **is,

Select cell **D2**, enter the formula ** =FORECAST.LINEAR(B1,C3:C14,B3:B14), **and press “

**Enter**”.

The calculated result is “**49.67174903**”, as shown above along with the graph.

#### Example #3

We will calculate the **Interpolate **using the **FORECAST function** for thevalue of x and y.

In the table, the data is,

- Cell B1 contains the x values.
- Column A contains the
**known_xs**values. - Column B contains the
**known_ys**values.

The procedure to calculate the **Interpolate **using the **FORECAST formula **is,

Select cell **C2**, enter the formula ** =FORECAST.LINEAR(B1,B3:B7,A3:A7), **and press “

**Enter**”.

The calculated result is “**3.3**”, as shown above along with the graph.

### Important Things To Note

- I
**nterpolation**using the**Forecast**is commonly used because it is fast and precise, easy to use, and time-saving if the table values are closely spaced. - This method is used to evaluate values for geographical data points.
- If the cell ranges of the
and the*known_xs*argument values are not the same sizes, we will get the*known_ys***“#NA” error.**

### Frequently Asked Questions (FAQs)

**1. What does the Linear Interpolate function do in Excel?**

Linear Interpolation helps users understand the relationship between x and y coordinates on datasets and graphs, and uses them to estimate new coordinates. The **FORECAST function** is used to calculate **Linear** **Interpolate in Excel**.

**2. How does the Interpolate function work in Excel?**

We can work with the **Interpolate** **function** as follows:**1)** Select an empty cell for the output.**2)** Type **=FORECAST(** in the selected cell. [Alternatively, type **=F** or **=FORE **and double-click the **FORECAST.LINEAR** **Interpolate function **from the list of suggestions shown by Excel.**3)** Enter the arguments as cell values or cell references and close the brackets.**4)** Press the “**Enter**” key.

For instance, we will calculate the **Interpolate in Excel** using the **FORECAST function** for thevalue of x and y.

In the table, the data is,**• **Cell B1 contains the x values.**• **Column A contains the **known_xs** values.**• **Column B contains the **known_ys** values.

The procedure to calculate the **Interpolate in Excel** using the **FORECAST formula **is,

Select cell **C2**, enter the formula ** =FORECAST.LINEAR(B1,B3:B5,A3:A5), **and press “

**Enter**”.

The calculated result is “

**17.07894737**”, as shown above with the graph.

**3. Where is the Interpolate Function in Excel?**

The **Interpolate in Excel’s Forecast formula **is found as shown below.

Choose an empty cell → select the **“Formulas” **tab → go to the “**Function Library**” group → click the **“More Functions…”** option drop-down → select the **“Statistical” **option right arrow → select the **“FORECAST.LINEAR”** option, as shown below.

### Download Template

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