Clean, chart and summarise a CSV in your browser

Nine free tools for the jobs between a messy export and a finished report. Paste a table to start. Nothing you paste or open leaves your device.

The CSV cleaner on an example export

Open the cleaner

Trim whitespace: 3 cells
Collapse internal spaces: 2 cells
Remove empty rows: −1 row
Remove empty columns: −1 col
Remove duplicate rows: −1 row
Dates to ISO 8601: 6 cells
Normalise numbers: 7 cells

Example: the first six cleaned rows
Row	Name	Email	Signed up	Country	Plan	Amount
1	Ana Souza	ana.souza@example.com	2024-02-03	Brazil	Pro	1200.00
2	Ben Carter	ben.carter@example.com	2024-02-14	UK	Basic	49.50
3	Chloe Martin	chloe.martin@example.com	2024-02-21	France	Pro	1200.00
4	Deepa Rao	deepa.rao@example.com	2024-03-05	India	Team	3450.00
5	Erik Larsen	erik.larsen@example.com	2024-03-05	Norway	Basic	49.50
6	Fatima Idris	fatima.idris@example.com	2024-03-09	Nigeria	Pro	1200.00

Changed cell 17 cells changed and 2 rows removed, in invented data

The tools

CSV cleaner New Trim spaces, remove duplicate and empty rows, fix dates and numbers, split, merge and rename columns, then download a clean CSV. Each step can be switched off again. CSV to bar or line chart Paste a table and get a bar or line chart you can download as a clean SVG, with every value also shown as a table. Pie and donut chart maker Labels and values in, a pie or donut chart out, with percentages worked out and small slices folded into "Other". Histogram maker A histogram of any column of numbers, with the Sturges, Freedman–Diaconis, Scott, square-root and Rice bin counts shown side by side. Scatter plot with linear regression Plot two columns against each other and fit a least-squares line, with slope, intercept, r and r² explained. Summary statistics calculator Mean, median, mode, standard deviation, quartiles by three conventions, and IQR outliers for a list of numbers. Pivot table and group-by summarizer Group rows by one or two columns and sum, count, average or take the median of another, with totals. CSV to Markdown and HTML table converter Turn CSV or pasted spreadsheet cells into a Markdown table or clean, accessible HTML, with numbers right-aligned. JSON to CSV converter (and back) Flatten an array of JSON objects into CSV columns, or turn CSV into JSON with sensible number and boolean handling.

Which tool answers which question

Start from what you want to know, not from the chart type you have seen most often.

Your question	Form that answers it
Is this export clean enough to use?	CSV cleaner
How does a value change over time?	Line chart
Which category is bigger?	Bar chart
What share of one total is each part?	Pie or donut, 2–6 parts
How are the values spread out?	Histogram
Do two measurements move together?	Scatter plot with a fitted line
What is typical, and what is unusual?	Summary statistics
What is the total per group?	Pivot table

Who this is for

Anyone who has a table of numbers and needs one specific thing from it quickly: a clean copy of a messy export, a chart for a slide, the median of a column, totals by region, or a README table from a spreadsheet. The tools suit students checking homework, analysts who need a figure without opening a notebook, and developers moving data between JSON, CSV and Markdown.

What is different here

Your data stays on your device. Every tool is JavaScript running in your browser tab. Nothing you paste or open is uploaded, so there is no account to create and nothing to delete afterwards. The privacy page explains how to check this yourself.

The method is on the page. Each tool names the formula or rule it uses. Where respected conventions disagree, as they do for quartiles and histogram bin counts, all of them are shown rather than one being picked silently. The cleaner asks, rather than guesses, when a date could be day-first or month-first. Each page also says where the tool stops being the right one.

Charts are plain SVG. Downloads are small vector files that stay sharp at any size and open in browsers, design tools and current versions of Office. Colours come from a fixed palette chosen to stay distinguishable for the common forms of colour blindness, and every chart is paired with a table of the values it shows. The full list of methods is on the about page.