Format Labels, Legends, Gridlines in LibreOffice Calc

Customizing chart elements in LibreOffice Calc improves the readability and visual presentation of your spreadsheets. This guide provides straightforward instructions on how to insert and format chart data labels, customize legend keys, and adjust major and minor gridlines to create clean, professional data visualizations.

Entering Chart Edit Mode

Before modifying any chart component, you must enter Chart Edit Mode: 1. Double-click the chart in your Calc sheet. A gray border with black selection handles will appear around the chart boundary. 2. Alternatively, right-click the chart and select Edit.

Formatting Chart Data Labels

Data labels display exact values, percentages, or category names directly on chart elements (bars, columns, pie slices, or line points).

Adding and Formatting Labels

  1. In Chart Edit Mode, right-click on the data series (e.g., a bar or data point) you wish to label.
  2. Select Insert Data Labels.
  3. Right-click the newly added labels and choose Format Data Labels… (or double-click any label).
  4. Use the dialog box tabs to customize:
    • Data Labels: Check options to display values as numbers, percentages, or category text. Set label placement (e.g., Above, Below, Center, Inside, or Outside).
    • Font & Font Effects: Change font style, size, color, and text effects.
    • Numbers: Uncheck Source format to define custom currency, decimal, or percentage formats.
    • Border & Area: Add background colors or outline borders around the labels.
  5. Click OK to apply the changes.

Formatting Legend Keys and Layout

The chart legend identifies the data series represented by different colors or markers.

Customizing the Legend

  1. In Chart Edit Mode, right-click the legend area and select Format Legend… (or double-click the legend).
  2. Adjust settings across the available tabs:
    • Position: Choose the placement of the legend relative to the chart (Left, Right, Top, or Bottom).
    • Borders & Area: Add a border line style or fill the legend box with a solid background color, gradient, or pattern.
    • Transparency: Adjust the opacity of the legend background.
    • Font: Modify the text size and typeface used for the series names.
  3. Click OK.

Renaming Legend Entries

To rename legend keys, update the header cells directly in your source data range, or: 1. Right-click the chart and select Data Ranges…. 2. Navigate to the Data Series tab. 3. Select the target series and update the cell reference under Range for Name.

Formatting Chart Gridlines

Gridlines provide reference lines across the chart area to make reading values easier.

Inserting Gridlines

  1. In Chart Edit Mode, go to the top menu and select Insert > Grid.
  2. Check the boxes for the axes where you want gridlines displayed (e.g., X axis or Y axis, for either Major grid or Minor grid).
  3. Click OK.

Styling Gridlines

  1. Right-click directly on any visible gridline in the chart wall.
  2. Select Format Grid… (or navigate to the target axis grid via the chart element drop-down on the formatting toolbar).
  3. In the Line tab:
    • Style: Choose solid, dashed, or dotted lines.
    • Color: Select a subtle color (e.g., light gray) to avoid cluttering the chart.
    • Width: Set the line thickness.
    • Transparency: Adjust visibility for a softer look.
  4. Click OK to finish.