How to Make a Line Graph That Shows the Trend Clearly
Updated · 2 min read
Line graphs show how something changes across an ordered sequence, most often time. The slope of the line carries the message. Here’s how to make one with the line graph maker.
1. One row per time period
Put periods (dates, months, years) in the first column in chronological order, and one column per line. Make sure the periods are evenly spaced. If a month is missing, add the row and leave its value blank rather than skipping it, otherwise the line will appear to jump.
2. Leave missing values blank, never zero
A zero is a measurement. A blank is the absence of one. The tool draws a gap for blank cells; tick “Connect across blank cells” if you prefer to bridge it, and say so in your caption.
3. Choose the y-axis range deliberately
Unlike bar charts, line graphs don’t need to start at zero, because the message is change, which comes from slope and position. Zoom in to show meaningful variation, but don’t exaggerate trivial changes. If the absolute level matters, tick “Start y-axis at zero”.
4. Keep multiple lines readable
- Limit yourself to about five lines; highlight one and gray out the rest if you need more context.
- Use different marker shapes, which is on by default, so lines can be told apart in grayscale.
- Order the legend to match the order of the lines at the right-hand end.
5. Straight, smooth or stepped?
Straight lines are the most honest default. Smooth lines look polished. Ours use monotone interpolation, so they never overshoot real values. Stepped lines suit values that change at discrete moments, such as interest rates or prices.
6. When to use something else
- Parts of a total over time: a stacked area chart.
- Two measures with different units: a combination chart with a secondary axis.
- Relationships between two measured variables: a scatter plot.