# How to Find Slope of Logarithmic Graph in Excel (with Easy Steps)

By adjusting a few axis format variables in Excel, we can simply plot a log-log graph. Both axes in the log-log or natural log-log graph are really on a logarithmic scale. Similar to the equation y = c. xa, this graph illustrates whether the variables are in a constant power relationship. In this case, the X and Y are related by a power of ‘a’ as in the image below.

• The line should have a smaller curve if a dataset derived from this equation is shown using a logarithmic scale.

### Step 1 – Create a Logarithmic Graph by Using the Charts Tool of Excel

• Select the Scatter Chart from the Charts group under the Insert tab.

• A blank chart will appear.
• Right-click on the chart and choose the command Select data from the context menu.

• A new window titled Select Data Source will appear. Click the Add command icon in that window.

• Choose the range of cells that we will use as data for the X-axis and the Y-axis in the following window.
• Choose the cell address that currently has the cells and cell name in it to insert the title there.

• Click OK.

• Right-click on the labels for the Horizontal Axis to generate the logarithmic graph.
• Select Format Axis from the context menu.

• It will reveal a new side panel. Select the Logarithmic scale checkbox and enter Base 2.7 under the Axis Options in the Format Axis side panel.
• Set Vertical Axis Crosses to Automatic as well.

• Similar to the y-axis, check the Logarithmic scale checkbox for the x-axis under the Axis Options in the Format Axis side panel.

Read More: How to Calculate Slope and Intercept in Excel

### Step 2 – Find the Slope of the Logarithmic Graph

We have data that could fit the theoretical y = c. xa curve. The slope of a natural log-log plot is equal to the exponent a‘s value, which is calculated as

`a=ln(y2)-ln(y1)/ln(x2)-ln(x1)`
• Select Add Trendline to find the equation of our data like the image below.

• Select Exponential as the trendline like in the following image.

• Select Display Equation on Chart in the Trendline Options.
`y = 12.484e``0.7387x`

• We will get the following equation to find the slope in each point of our x-value for this example the x-values are Day.
`dy/dx=12.484 x 0.7387 x e``0.7387x`
• Using the differential equation, we will get the slope in Excel like the following image.

The formula is as follows:

`=12.484*0.7387*EXP(0.7387*B5)`
• Drag the fill handle down to complete the series.

Read More: How to Find the Slope of a Line in Excel

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Al Ikram Amit

Al Ikram Amit, holding a BSc in Naval Architecture & Engineering from Bangladesh University of Engineering and Technology, serves as a key Excel & VBA Content Developer at ExcelDemy. Driven by a profound passion for research and innovation, he actively immerses himself in Excel. In his role, Amit not only skillfully addresses complex challenges but also exhibits enthusiasm and expertise in gracefully navigating tough situations, emphasizing his steadfast commitment to consistently delivering exceptional, high-quality content that adds significant... Read Full Bio

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