What a line graph is for
A line graph connects each point to the next one with a straight segment. That connection is a claim: it says the points belong to an ordered sequence, so the step from one to the next means something. Time is the usual order. Months, quarters, years, or any other ordered axis work too. Unordered categories do not. If your labels are "red, green, blue" or "Ohio, Texas, Maine," a line would join them in an order you invented. Use a bar chart for those instead.
This is the one fact that separates this page from every other chart page on the site. A bar chart compares amounts across categories you supply. A line chart shows how one or more series move along an ordered axis. Paste the wrong shape and the picture will mislead you before you notice.
The data shape this tool expects
Two or more columns. The first column holds the time points or ordered labels. Each column after that holds one series of numbers, one row per time point. A header row is optional. The tool treats the first row as headings only when the rows below it are numbers or dates and the first row is not, so a sheet of plain text never loses its first row of data.
Delimiters are found automatically. A tab wins if any line contains one, which is what a copy out of Excel, Google Sheets or Numbers puts on the clipboard. Otherwise the tool picks a comma, semicolon or pipe, whichever splits the lines most consistently. A single column of numbers needs no delimiter at all. Quoted fields follow the ordinary CSV convention, so a quoted field may contain the delimiter and a doubled quote inside quotes is one quote [RFC 4180].
Dates are read in several forms: 2026-03-04, 2026-03, 2026, 2026 Q3, Mar 2026, March 4 2026, and slash or dot forms such as 03/04/2026. Whether a slash form is day-first or month-first is decided from the whole column. Any value whose first number is above 12 settles it. When a column is genuinely ambiguous the month-first reading is used, and the page says which reading is in force with a control to switch it. The precision you wrote is kept, so a column of years is labelled by year rather than by day.
Numbers are read with the same care. The decimal separator is decided once per column from all of its values, not cell by cell, because "1,234" is one thousand two hundred and thirty-four in a US sheet and 1.234 in a German one. Currency symbols, trailing units and spaces are ignored. A value in parentheses is negative, as accountants write it. A trailing per cent sign is dropped, not divided, so 45% charts as 45. Empty cells and spreadsheet errors like n/a, #DIV/0! and #VALUE! are counted as empty rather than as zero, so one n/a cannot turn a column of numbers into a column of text.
A worked example
Suppose you paste four rows of quarterly revenue for two product lines:
| Quarter | Product A | Product B |
|---|---|---|
| 2026 Q1 | 120 | 80 |
| 2026 Q2 | 135 | 95 |
| 2026 Q3 | 150 | 110 |
| 2026 Q4 | 170 | 130 |
The first column is read as quarters, not as text, so the horizontal axis is spaced by time. Two lines are drawn, one per product. The vertical axis fits the data by default, so it runs from about 80 to 170 rather than from zero. That choice is explained below.
Multiple series, gaps, and markers
Two or three lines on one chart are usually readable. Past that, the lines cross and the colors stop helping. If you have five regions or ten sensors, split them into small charts side by side. Each small chart keeps its own scale honest and lets a reader compare shapes without untangling a knot.
Gaps matter. If a value is missing, the tool leaves a break in the line rather than drawing through it. A line drawn through a gap invents data you did not paste. If the gap is short and the series is smooth, you may prefer to leave the break visible and note it in the caption.
Point markers are optional. With few points, markers help a reader see where the actual observations sit. With many points, markers crowd the line and add nothing. A good rule: show markers when you have fewer than about twenty points per series.
Should the vertical axis start at zero?
For bar charts and histograms, yes. The length of the bar is what encodes its value, so cutting the axis short exaggerates the difference between bars. Tufte calls the ratio between the size of an effect shown in a graphic and the size of the effect in the data the "lie factor" [Tufte 1983].
For line charts, the answer is often no. The point of a line is the change, not the absolute level. If your values run from 1,240 to 1,310, a zero-based axis flattens the whole story into a straight line. The tool fits the vertical axis to the data by default for line charts and scatter plots. You can override that default on the page and force a zero start if your audience expects it.
A logarithmic vertical axis is also offered for line and scatter charts. It is only applied when every value is above zero.
What you get, and where to go next
Download PNG, drawn at twice the chart's size so it stays sharp in a document or slide, or SVG, which stays sharp at any size and opens in Illustrator, Inkscape, Figma or Word. There is no watermark, no sign-up and no limit on the number of charts. The chart carries a title and a description in the file itself so a screen reader can announce it, and the figures behind every chart are also shown as a table on the page, because a chart is an image and an image needs a text equivalent [WCAG 2.2, success criterion 1.1.1].
The chart is drawn by code running in your own browser. Pasted text and uploaded files are read in the browser and are never sent to a server. The "copy link to this chart" link carries the data in the fragment of the URL, the part after the # that browsers do not transmit to a server. A link has a practical length limit of about 7,800 characters, and the page says plainly when a dataset is too large to share that way.
If your data is two measurements per observation and you want to see whether they move together, use the scatter plot maker. If you are comparing amounts across categories, use the bar graph maker. If you want the shape of one column of numbers, use the histogram maker. If you want parts of one whole, use the pie chart maker. The full references for every source named here are on how it works.