Yes, it is possible to draw Kaplan Meier survival curves in Excel without using an add-in. Here are the steps to create a basic Kaplan Meier survival curve in Excel:

1. Enter your data into Excel. You will need two columns: one for the time variable (usually in months or years) and one for the survival status (1 for alive, 0 for dead).
2. Sort your data by the time variable in ascending order.
3. Create a new column for the number at risk at each time point. This is the number of subjects who have not yet experienced the event (death) at each time point. For the first time point, this will be equal to the total number of subjects. For subsequent time points, subtract the number of deaths from the previous time point from the number at risk at the previous time point.
4. Create a new column for the proportion surviving at each time point. This is the number at risk at each time point divided by the total number of subjects.
5. Create a line chart with time on the x-axis and proportion surviving on the y-axis. Add error bars to the chart using the number at risk at each time point as the error bar values.
6. Format the chart so that the line falls straight down toward the x-axis after each data point. To do this, right-click on the line and select "Format Data Series." Under "Line Style," select "No line" for the "Dash type" and "Cap type" options.
7. Add any additional formatting or labels as desired.

That's it! With these steps, you can create a basic Kaplan Meier survival curve in Excel without using an add-in.