This method will guide you to insert an in-cell bar chart with the Data Bars of Conditional Formatting feature in Excel. Please do as follows:

1. Select the column you will create in-cell bar chart based on, and click Home > Conditional Formatting > Data Bars > More Rules. See screenshot:

2. In the New Formatting Rule dialog box, please:
(1) In the Format all cells based on their values section, please specify the Format Style as Data Bar;
(2) Check the Show Bar Only option if you want to hide source data amount the data bar;
(3) In the Bar Appearance section, please specify the bar color from the Color drop-down list. See screenshot:

3. Click the OK button.

And now you will see the in-cell bar is added to the selected column. See screenshot:

This method will apply the REPT function to insert an in-cell bar chart in Excel easily.

1. Select a blank cell beside the source data, type the formula =REPT("g",B2/200) into it, and drag the AutoFill Handle down to other cells.
Note: In the formula =REPT("g",B2/200), B2 is the first cell in the source data.

Now the formula returns a series of result in each cell.

2. Keep the formula cells selected, go to the Home tab, and:
(1) In the Font box, type Webdings, and press Enter key;
(2) Select a font color from the Font Color drop-down list;
(3) Change the font size as you need.

Now you will see the in-cell bar chart is added to the formula cells. See screenshot:

If you need to compare two sets of values and show the difference between them as in-cell bar chart, you can apply the Difference Comparison Chart of Kutools for Excel to get it done.

1. Click Kutools > Charts > Difference Comparison > Difference Comparison Chart to enable this feature.

2. In the Difference Comparison Chart dialog, you need to:
(1) Check the Mini Chart option;
(2) Specify the ranges in the Data Series 1, Data Series 2, and Output boxes successively;
(3) Click the Ok button.

Then the comparison bar chart is created and added in the specified output range. See screenshot: