Line Graph Maker
Plot one or more series over time. Missing values break the line instead of faking a trend.
About this tool
Line graphs are for things measured repeatedly over the same axis — months, days, trials, distances. The eye reads the slope before it reads any number, which is exactly what you want when the question is "is this going up, and how fast?" Two or three lines on the same axis answer a harder question: are they moving together, or has one started to pull away?
One rule here is worth knowing about, because tools differ on it: a missing value breaks the line rather than being joined across. A line drawn straight through a month you never measured is indistinguishable from a month that happened to be smooth, and that is a difference readers deserve to see. If a gap in your chart is a surprise, the data has a hole in it — which is usually worth knowing before the chart goes into a report.
The vertical axis is scaled to round numbers with headroom above the highest point, and labels along the horizontal axis are thinned automatically when they would otherwise overlap. Everything runs on this page — no upload, no account, and the exported PNG is produced by your own browser.
Frequently asked questions
How should the data be arranged?
First column is the label for each point — months, dates, week numbers, anything — and every column after it becomes a line. So three columns give you two lines sharing one horizontal axis, each with its own colour and a legend entry. Paste it straight from a spreadsheet; the header row becomes the series names.
What happens where data is missing?
The line breaks. An empty cell is treated as missing, not as zero, so the gap is drawn as a gap. This is deliberate: joining across a missing month draws a straight line through data you never collected, which looks like a smooth trend and is really an invention. A break tells the truth about what you have.
Why did the dots disappear on my chart?
Point markers are drawn up to thirty points per series and dropped beyond that. With a year of daily data the markers would overlap into a solid band and hide the very shape you are trying to read, so past that threshold only the line is drawn.
Why does my year axis show whole numbers only?
When every label is a whole number and the range is small, tick marks are forced to whole steps. Without that rule a 2019–2021 axis gets half-year ticks, and rounding turns them into "2019 2020 2020 2021 2021" — the same year printed twice. Counts, years and week numbers are all whole things, so the axis stays whole.
Can I save the chart?
Download PNG re-renders it at 2x resolution through the browser Canvas API, sharp enough for a slide or a report. Nothing is uploaded at any point — the data is parsed, drawn and exported entirely on this page.