What is a line graph?
A line graph plots values in order along the horizontal axis and joins them with a line. Because the points are connected, your eye follows the direction of change: rising, falling, flat, or turning. That is why line graphs are the standard way to show anything over time, from monthly sales to daily temperature.
Use a line graph when the order of the data matters. If your categories could be shuffled without losing meaning, such as stores or product names, a bar graph is the better choice.
How to read a line graph
- Direction: is the line going up or down overall? Compare the start and the end rather than the biggest bump.
- Steepness: a steeper section means faster change in that period.
- Turning points: where the line changes direction often lines up with an event, such as a promotion, a holiday or a price change.
- Gaps between lines: with several series, a widening gap means one is pulling ahead.
SheetGlance writes these observations for you: the highest and lowest points, how the second half compares with the first, and which series grew fastest.
Line graph or bar graph?
| Line graph | Bar graph | |
|---|---|---|
| Best for | Trends over time | Comparing separate categories |
| Horizontal axis | Ordered: dates, months, years | Any order: names, groups |
| Many points | Works well with 100+ points | Gets crowded after about 15 bars |
| Several series | Clear up to about 5 lines | Stack or group the bars |
A common case for both: monthly sales for one year works as either. Use a line graph if the story is the trend, and bars if the story is which month was biggest.
How to make a line graph in Excel
- Put the dates or months in the first column and each series in its own column, with a header row.
- Select the whole range, including the headers.
- Go to Insert → Charts → Insert Line or Area Chart → Line (or Line with Markers).
- Use the + button next to the chart to add axis titles and a legend.
If your sheet has one row per order rather than one row per day, you first need a PivotTable to add up the values by date. SheetGlance does that step for you: it groups rows by day, week or month automatically.
How to make a line graph in Google Sheets
- Select your data, including the header row.
- Choose Insert → Chart.
- In the Chart editor, under Setup → Chart type, pick Line chart.
- Under Customise, set titles, colours and point size.
Tips for a clearer line graph
- Keep it to five lines or fewer. With more, split them into several small graphs.
- Start the vertical axis at zero when you compare amounts; zoom in only when small changes matter, and say so.
- Group daily data by week when the line looks too jagged to read.
- Label the line directly or keep the legend close to it.