Python Charts - Stacked Bar Charts with Labels in Matplotlib With a stacked bar chart, it's a bit trickier, because you could add a total label or a label for each sub-bar within the stack. We'll show you how to do both. Adding a Total Label We'll do the same thing as above, but add a step where we compute the totals for each day of the week and then use ax.text () to add those above each bar.