Bar Chart Maker
Enter labels and values to build a bar chart and export PNG.
The bar chart maker lets you enter rows of label and value, instantly rendering a clear bar chart on the canvas with an optional title. Scales and proportions are calculated automatically, and you can export a PNG for reports, slides, or handouts. Everything is drawn locally in your browser and nothing is uploaded.
Tool area
How to use
- Enter a chart title (optional).
- Fill in a label and value on each row.
- Click "Add row" to add more data; the chart updates instantly.
- Click "Export PNG" to download the image.
Use cases
- Make a bar chart of monthly sales or visitor counts.
- Compare scores across classes or groups.
- Show survey option counts in a report.
Content and verification review:
How to verify a Bar Chart Maker result before relying on it
This section covers Bar Chart Maker’s live-redraw behavior, what happens to invalid rows, and the label-truncation rule — details that matter for whoever reads the chart, not just whoever builds it.
The chart redraws on every keystroke — there is no separate Generate step
The page loads with four rows already filled in: Jan 120, Feb 150, Mar 90, Apr 180, and the four bars are drawn immediately. Change any label or number and the canvas redraws instantly; the only button that does something separate is Export PNG, which re-runs the same drawing code before triggering the download — so whatever is on screen is exactly what gets saved, with a white background regardless of your site theme.
A row with a blank, non-numeric, or negative value is dropped silently — not flagged
Clear the Apr value, type a word into it, or make it negative, and that bar simply disappears from the chart with no error message; the remaining valid rows still render normally. Only when every single row is invalid does the canvas go blank and show “add at least one valid entry.” A typo in one row raises no warning — the chart just looks like it has one fewer bar than expected, and you have to notice the mismatch yourself.
Long labels are cut to 9 characters plus an ellipsis, with no tooltip to recover the rest
A label longer than 10 characters is truncated under its bar to its first 9 characters followed by “…” (for example, “Northeast Region Sales” becomes “Northeast…”), and the full text is not shown anywhere else on the chart. Value labels above each bar are always rounded to 2 decimal places and formatted with thousands separators (1234.567 becomes “1,234.57”), even if you typed in a whole number.
Acceptance checklist
- Every row you expect to see on the chart has both a label and a non-negative number — a blank or negative value drops that row without any error.
- Labels longer than 10 characters have been shortened before relying on the chart, since the canvas truncates them to 9 characters plus “…” with no way to see the rest.
- The bar count on screen matches the number of rows you filled in — if they don’t match, at least one row was silently skipped.
- Export PNG was checked against the on-screen chart, since it redraws from the current inputs onto a fixed white background rather than capturing a themed screenshot.
FAQ
- How many data rows can I add?
- No hard limit, but too many makes bars narrow; keep to a dozen or so for clarity.
- Can values be decimals?
- Yes, decimals are supported; empty or invalid rows are ignored.
- What format is the export?
- A PNG image with a white background, ready to paste into documents or slides.
- Is my data uploaded?
- No, all drawing happens locally in your browser.
- Can I chart negative numbers?
- It focuses on non-negative values; negative rows are ignored, which suits typical counts and ratios.
Privacy & local processing
🔒 This tool runs entirely in your browser. No data is uploaded to any server.
All chart drawing happens locally in your browser; your data is not uploaded.
Trust & usage note
This tool runs mainly in your browser. Your input is not actively uploaded to a server. Avoid entering highly sensitive data. Results are for reference only.
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