Can I make a chart from CSV without uploading the data?
Yes. The chart maker parses the selected CSV or JSON table in the current browser tab, lets you choose the label and numeric value columns, and draws the result with the packaged Chart.js library. It does not send the table to a chart service or an AI service. You can inspect the values in a text table before saving a 2,000 by 1,125 pixel PNG or a JSON file containing the selected data and chart settings.
How to use the tool
Add the source table
Paste CSV or a JSON array of objects, or choose a local .csv or .json file within the published limit.
Choose columns and chart type
Select one label column, one plain numeric value column, and a bar, line, pie or doughnut chart.
Review and download
Check the text summary and data table, then save a high-resolution PNG or portable chart-data JSON file.
At a glance
- Processing
- In the current browser tab
- Input formats
- CSV or a JSON array of objects
- Chart types
- Bar, line, pie and doughnut
- Maximum chart rows
- 1,000; pie and doughnut limited to 50 slices
- Image export
- PNG at 2,000 × 1,125 pixels
- Other export
- Selected data, summary and chart settings as JSON
Prepare a small, explicit table
The first row of CSV should contain unique headings. JSON input should be an array of similarly shaped objects. A chart needs at least two columns: one for labels and one whose every value is a finite number.
Numbers use a deliberately narrow, locale-neutral syntax. Remove currency symbols and thousands separators before reading the data. This avoids silently treating text such as “1,200” or “$12” as a different number than the source intended.
- Summarise large datasets before charting so the result remains legible.
- Use short, meaningful labels and a title that says what the values measure.
- Keep units in the heading or title rather than repeating them in each cell.
- Review warnings and the text table before relying on the image.
Choose a chart that matches the comparison
Bar charts are usually appropriate for comparing categories. Line charts can show an ordered sequence, especially change over time. Pie and doughnut charts show parts of a whole only when every slice shares the same total and the number of categories remains small.
The chart is a presentation of the supplied rows, not a statistical analysis. It does not infer missing values, aggregate duplicate labels, confirm units, prove causation or verify the underlying source.
Keep the data available alongside the picture
Canvas produces pixels, which are not a complete text alternative by themselves. The tool therefore provides the chart title, a numeric summary and a real HTML table for keyboard and assistive-technology users. The JSON download also preserves the selected labels and values for later review.
A downloaded PNG may still need a caption, adjacent data table or alternative text when it is published in a document or website. Describe the important comparison or trend rather than only saying that an image is a chart.
Important limitations
- The tool plots one numeric series at a time and does not aggregate, sort or statistically analyse the rows.
- Inputs are limited to the shared 1.5 MB parser boundary and charts to 1,000 rows; circular charts are limited to 50 slices.
- Every selected value must be a plain finite number without a currency sign, percent sign or thousands separator.
- The PNG has a fixed 16:9 pixel size and is not a vector or print-quality certification.
- Local processing protects the table from this application server, but the downloaded files remain the user’s responsibility.
Questions people ask
Does the chart maker upload my CSV or JSON?
No. The selected text is parsed and charted in the current browser tab. Chart.js is bundled with the application, so no remote chart API is needed.
Why is my value column not listed?
A numeric value column must contain a plain finite number in every row. Remove blanks, currency symbols, percent signs and thousands separators, then read the data again.
Which chart type should I choose?
Use bars for category comparisons and a line for an ordered sequence. Use pie or doughnut only for a small set of parts that meaningfully share one whole.
Is the PNG enough for an accessible report?
Usually not by itself. Include a useful caption or alternative text and keep the values or a data table available alongside the image.
Primary and project sources
- Chart.js project — Chart.js contributorsPrimary project source, release history and MIT licence for the browser chart renderer used by the tool.
- Chart.js documentation — Chart.js contributorsPrimary documentation for chart types, configuration, responsive canvases and data structures.
- HTML canvas — WHATWGPrimary browser standard for the canvas bitmap and accessibility fallback content.
- File API — W3CBrowser file-selection and Blob interfaces used for local input and generated downloads.
- Web Content Accessibility Guidelines 2.2 — W3C Web Accessibility InitiativeNormative requirements relevant to text alternatives, structure and non-text content.