Line Graph Maker

How to Use the Line Graph Maker

1. 1. Enter your data. One x value per line, then its y value: Week 1, 18 or 2019, 4.2. Columns pasted from a spreadsheet are read as they are; use semicolons between cells if your numbers have decimal commas.
2. 2. Add a column per line. Each extra y column becomes another line. Start with a header line — Week, Class A, Class B — to name them in the legend. Leave a cell empty where a value is missing and the line breaks there instead of guessing.
3. 3. Check the x-axis. When every x value is a number, the points are spaced to scale, so the gap from 2015 to 2020 looks five years long, not one step. For labels such as months or conditions, choose Categories, evenly spaced.
4. 4. Style and export. Add the title and axis titles, choose whether each point is marked and labeled, start the y-axis at zero if that suits your data, switch on APA style for a paper, and download the SVG or PNG.

When to Use a Line Graph

A line graph shows how a quantity changes across an ordered variable — usually time, but also dose, temperature, grade level or trial number. Joining the points asserts that they belong to one sequence, so use a line only when the x values have an order and the change from one to the next means something.

• Good fits: scores across the weeks of a term, a measurement over repeated trials, a rate by year, the means of two conditions at several time points.
• Use a bar graph instead for unordered categories such as majors or countries. A line from Biology to Chemistry implies a trend that cannot exist. The Bar Graph Maker handles these.
• Use a scatter plot when both variables are measurements and each point is a separate case — hours studied against exam score — rather than one series over time.

Why the Lines Are Straight

Each segment joins two observations with a straight line. Spreadsheet programs often offer smoothed curves, but a smoothed line passes through values nobody measured and can bulge above a maximum or dip below zero between points. A straight segment makes the plainest claim about the space between two observations. For the same reason, an empty cell leaves a gap: bridging it would draw a value you do not have, so the tool notes the gap instead.

Every series also gets its own marker shape — circle, square, triangle, diamond — as well as its own color, so the lines can be told apart in grayscale or with a color-vision deficiency. With markers off, a point with no neighbor on either side is still marked, since a segment needs two points.

Formatting a Line Graph as an APA Figure

In APA 7, the figure number (bold) and title (italic title case) sit above the image in your paper, and a note can follow below it. APA style figure takes the title out of the image and removes the gridlines; the legend stays inside the image, where APA puts it, and Copy number and title copies the caption with its formatting.

• Say in the note what each point is — a single measurement, a mean, a median — and what any error bars show: Note. Points are class means; each class had 24 students.
• Title both axes with units: Minutes per day, Week of term.
• A line graph shows values by position, so its y-axis need not start at zero. The labels show where the axis starts; do not crop it so tightly that a small change looks dramatic.
• Keep to a few lines. Past four or five series, split them into separate panels or highlight the one that matters.

Common Line Graph Mistakes

• Unequal intervals drawn as equal. Measurements from weeks 1, 2, 4 and 8 spaced evenly make the trend look steadier than it is. Enter numeric x values and they are spaced to scale.
• Joining unordered categories. A line between categories that have no order is a bar graph drawn badly.
• A second y-axis. Two scales on one plot invite readers to compare lines whose crossing points depend only on how each axis was scaled. Make two graphs, or index both series to a common starting value.
• Smoothing. A curve through the points invents values between them; if you fitted a model, show it as a separate line and say so.

Frequently Asked Questions

How do I make a line graph with multiple lines?

Add one y column per line and a header row naming them: Week, Class A, Class B and then 1, 18, 15 and so on. Each column becomes a line with its own color and marker shape, and the header names appear in the legend. Up to eight lines get distinct colors.

How do I make a line graph with years on the x-axis?

Type the years as the first column. Because they are numbers, the points are spaced to scale — 2010, 2015 and 2016 are not evenly spaced — and the axis prints them without thousands separators (2024, not 2,024). If you want every year evenly spaced as a category, choose Categories, evenly spaced.

Should a line graph start at zero?

Not necessarily. A line graph shows values by position, not by length, so an axis that starts near the data is acceptable and often clearer. Start at zero when the size of the values relative to zero matters, and never crop the axis so tightly that a trivial change looks large. Tick Start the y-axis at 0 to force it.

How do I show missing data on a line graph?

Leave the cell empty. The line stops at the last value before the gap and starts again after it, instead of drawing a straight bridge across a value you did not measure.

What is the difference between a line graph and a scatter plot?

A line graph follows one or more series through an ordered variable such as time, joining consecutive points. A scatter plot shows the relationship between two measured variables, one point per case, with no line between the points — though it may carry a fitted trend line. The Scatter Plot Maker adds a least-squares line and r².

Can I use the graph in a paper or presentation?

Yes. Download the PNG (1,280 pixels wide) for documents and slides, or the SVG for a vector file that stays sharp at any size. For an APA paper, switch on APA style and paste the figure number and title above the image.