Excel can be a useful tool, with many applications for scientists, students, economists, analysts and many other professions. One of the unique functions of Excel is that it allows users to analyze and graph large amounts of data easily. People who have a knowledge of calculus can use the trendline function on the chart to calculate the area under a curve. For students who do not have a knowledge of calculus, there is another way of approximating the area under the curve.
Things You'll Need
 Calculator
Using the Trendline Equation

Rightclick on the curve under which you would like to find the area in the Excel chart. Click on the option to add a trendline.

Choose the type of line you think best fits the curve.

Choose the option to display the equation on the chart under the "Options" tab.

Find the definite integral of the equation displayed on the chart over the interval of which you would like to find the area. The value of the definite integral is the area under the curve. Knowledge of calculus is necessary for this step.
Approximating If the Points Are Evenly Spaced

Add up the y values of the data where you would like to find the area. You can do this by adding the values straight from the chart or by adding the values in the cells in the spreadsheet.

Find the distance between the points on the x axis if they are evenly spaced.

Multiply the sum of the y values and the distance between the x values. This product is the approximate area under the curve.
Tips & Warnings
 Try a couple of different types of lines to see which fits best.
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References
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