How to Use Integration in Excel to Find Area Under a Curve

The following dataset shows some coordinates of a random curve.

Step 1 – Set Data Properly and Create Scatter Chart

Set your data in order and select any cell of your data. Go to the Insert tab and from the Charts group, select a suitable chart type.
We have selected the Scatter with Smooth Lines and Markers option.

The scatter chart will be inserted.

Step 2 – Enable Trendline and Its Equation

Click on the Chart Area.
Click the Chart Elements button.
From the Trendline dropdown, select More Options.

The Format Trendline window will appear.

Click on the Polynomial and check the Display Equation on chart checkbox.

The following trendline equation will appear on the chart area.

Y = 7.331X² + 19.835X + 82.238

Step 3 – Find the First Integral and Calculate Area Under Curve

Create a table and insert the following formula in cell F24.

=F23-F22

Copy the trendline equation and paste it into cell E19.
Calculate the first integral with this equation using the following formula.

The first integral of Y is-

Y₁ = 7.331X³/3 + 19.835X²/2 + 82.238X+C

Enter the following formula (or match it with your data) in cell F22 and copy it with the fill handle in cell F23.

=7.331*E22^3/3+19.385*E22^2/2+82.238*E22

The area is calculated in cell E24.

Note:

The area under the curve is with respect to the X-axis. If you want to find the area under the curve with respect to the Y axis, flip the data horizontally, switch the axes and apply all the steps described.