How to add subscripts and superscripts into legends in excel

Firstly, I want the legend for Series 1 to be CO₂. So I’ll start by typing CO into a cell.

Go to the Insert Tab and select Symbols.

Use the dropdown list to find Superscripts and Subscripts.

This is where most of the superscript and subscript numbers are. I will select the subscript 2 and then click Insert.

The superscript 1, 2 & 3 are in a different place, if you want these numbers, scroll back up to the top and you will see them in the Latin-1 Supplement section.

Now, we have CO₂ in a cell, right click on the chart and click Select Data…

Then we will Edit the series.

Change the series name so that it is linked to the cell with CO₂ in it. Then click OK twice.

Now, for Series 1, there is CO₂ with a subscript 2, in the legend of the chart.