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Curve Fitting – Excel & Google Sheets

This tutorial will demonstrate how to create a curve fitting line in Excel & Google Sheets.

Creating Curve Fitting Line – Excel

We’ll start with the following data:

Starting Data X Y Series in Excel

Creating a Scatterplot

  1. Highlight data
  2. Select Insert
  3. Select Scatterplots
  4. Select the first Scatterplot

Create Scatterplot X Y Axis in Excel


Creating a Trendline

  1. Select the + Sign in the top right of the graph
  2. Select the arrow next to Trendline
  3. Select More Options

Create Trendline Curve in Excel Polynomial


4. Select the graph icon

5. Click Polynomial

Create Polynomial Curve Trendline in Excel


Changing Order of the Polynomial

As you can see, increasing the Order adds more of a curve and fits the line more closely.

Change Order of Polynomial Curve in Excel

However, be careful to avoid “over-fitting” the data. Generally there should be a good reason to increase the Order number.

Creating Curve Fitting Line – Google Sheets

Creating a Scatterplot

  1. Highlight data
  2. Select Insert
  3. Click Chart

Create Scatterplot Curve in Google Sheets


4. Click on the dropdown of the current Chart Type

5. Change it to Scatter Plot

Changing Graph to Scatterplot in Google Sheets

Creating a Curve Trendline

  1. Select Customize
  2. Click Trendline
  3. Select Polynomial
  4. Select which Polynomial Degree (same as Order explained in Excel)

Customize Trendline to Create Polynomial Graph

You can now see the final trendline with the curve as shown below.

Final Graph in Google Sheets with Polynomial Curve