Error bars are more complicated than necessary. You can draw a vertical, diagonal, or horizontal line by simply defining the endpoints. Here's the instructions for all:

Creating a Line on a Chart Using Two Points (Single Series, No Error Bars)

This method is versatile and works for vertical, horizontal, and diagonal lines. It's much simpler than using error bars or multiple series.

General Principle:

A line is defined by two points. This method uses two data points to plot the line directly.

Vertical Line:

Data: In two cells in a column (e.g., D1 and D2), enter the same number. This number represents the X-coordinate of your vertical line. For example: D1: 10 D2: 10 In two cells in another column (e.g., E1 and E2), enter two different numbers. These numbers represent the Y-coordinates that define the start and end points of your vertical line. For example: E1: 5 E2: 20 Horizontal Line:

Data: In two cells in a column (e.g., D1 and D2), enter two different numbers. These numbers represent the X-coordinates that define the start and end points of your horizontal line. For example: D1: 5 D2: 20 In two cells in another column (e.g., E1 and E2), enter the same number. This number represents the Y-coordinate of your horizontal line. For example: E1: 10 E2: 10 Diagonal Line:

Data: In two cells in a column (e.g., D1 and D2), enter two different numbers. These numbers represent the X-coordinates of your diagonal line. For example: D1: 5 D2: 15 In two cells in another column (e.g., E1 and E2), enter two different numbers. These numbers represent the Y-coordinates of your diagonal line. Critically, these Y-coordinates should not be the same. For example: E1: 10 E2: 25 For any line (vertical, horizontal, or diagonal):

Chart: Create an XY (Scatter) chart. Add a single series: Series X values: =Sheet1!$D$1:$D$2 Series Y values: =Sheet1!$E$1:$E$2 Key Advantages:

Simplicity: No error bars, no multiple series – just two points defining a line. Flexibility: Works for vertical, horizontal, and diagonal lines. Intuitive: Directly applies the concept of defining a line by two points. Essential Considerations:

XY Scatter Chart: This chart type is crucial for plotting based on numerical X and Y values. Numerical Data: Ensure you are entering numbers, not text, in the cells used for the X and Y coordinates. Unequal X and Y for Diagonals: Diagonal lines require that both the X and Y values of the two points are different. The relationship between the change in X and the change in Y determines the slope of the diagonal line.