How to Interpolate Missing Values in Google Sheets

Interpolating missing values in Google Sheets involves estimating the missing data points based on the existing data. You can use various methods to achieve this, such as using linear interpolation, polynomial interpolation, or other advanced techniques. In this guide, we will focus on linear interpolation using a simple formula.

Instructions

1. Open your Google Sheet containing the missing values.
2. Identify the range of cells where you want to interpolate missing values.
3. Create a helper column or row to calculate the interpolated values.
4. Use the formula to calculate the interpolated values based on the existing data points.
5. Copy the interpolated values to the original missing values.

Example

Let's assume you have the following dataset with missing values:

A      B
1    Year  Sales
2    2010  100
3    2011  120
4    2012  
5    2013  
6    2014  190

In this example, we want to interpolate missing values for the years 2012 and 2013 in column B, based on the sales data from 2010, 2011, and 2014.

Step 1: Create a helper column

Create a helper column (column C) to calculate the interpolated values. The header could be "Interpolated Sales".

A      B       C
1    Year  Sales  Interpolated Sales
2    2010  100     
3    2011  120     
4    2012          
5    2013          
6    2014  190     

Step 2: Use the formula to calculate the interpolated values

In cell C4, use the following formula for linear interpolation:

=IF(ISBLANK(B4), B3 + (B6 - B3) * (A4 - A3) / (A6 - A3), "")

This formula checks if the value in cell B4 is blank. If it's blank, it calculates the interpolated value based on the sales data from 2010, 2011, and 2014. If it's not blank, it leaves the cell empty.

Step 3: Copy the formula for other missing values

Copy the formula in cell C4 and paste it into other cells in the helper column with missing values (in this case, C5).

The updated table should look like this:

A      B       C
1    Year  Sales  Interpolated Sales
2    2010  100     
3    2011  120     
4    2012          140
5    2013          165
6    2014  190     

Step 4: Copy the interpolated values to the original missing values

Copy the interpolated values in column C (C4 and C5) and paste them as values (Paste Special > Paste values only) in the original missing values cells in column B (B4 and B5).

Now, your dataset should have the missing values interpolated:

A      B       C
1    Year  Sales  Interpolated Sales
2    2010  100     
3    2011  120     
4    2012  140    140
5    2013  165    165
6    2014  190     

Step 5: Remove the helper column

You can now remove the helper column (column C) if you don't need it anymore. Your dataset should now look like this:

A      B
1    Year  Sales
2    2010  100
3    2011  120
4    2012  140
5    2013  165
6    2014  190

You have successfully interpolated the missing values in your dataset using Google Sheets.