TOOL TOPIC
CSV & data tools
Handle common structured-data tasks such as CSV encoding checks, header differences, duplicates, merging, filtering, and extraction in the browser.
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Common tasks in this topic
Free tools for inspecting CSV encoding and headers, finding duplicates, merging or splitting files, extracting columns, and filtering rows.
1
Inspect CSV encoding and delimiters before importing
2
Merge, split, filter, and extract data files
3
Find duplicates and compare structured data
Start from the problem
You do not need to know the tool name first. Start from what is happening or what you need to finish.
Excel shows mojibake or puts everything in one columnSeparate encoding, delimiter, and row-shift problems by what you actually see.Start here →I want one clear mental model for CSVA durable guide to structure, encoding, and how spreadsheet apps interpret values.Understand CSV →I need to edit a CSV in Excel without damaging itWork from the untouched original through import, editing, export, and final validation.Follow the workflow →I only need a quick format or terminology checkJump to references for CSV / TSV, encodings and BOM, or line endings.Open references →
Tools in this topic
Choose the tool that most closely matches the task you need to finish.
CSV encoding & delimiter inspectorInspect likely encoding and comma, tab, semicolon or pipe delimiters.Open →Excel-damaged CSV checkerFind tab conversion, scientific notation and date-like coercion after Excel edits.Open →CSV header diff checkerCompare header names, order, missing columns and extra columns.Open →CSV duplicate finderFind duplicate values and row numbers in a selected column.Open →CSV row splitterSplit a large CSV into files with a chosen number of rows.Open →CSV mergerMerge multiple CSV files with matching headers.Open →CSV mojibake & character risk checkerFind emoji and special characters that often cause problems in Shift_JIS-based imports.Open →CSV ⇄ TSV converterConvert between CSV and tab-separated text in your browser.Open →CSV column extractorExtract selected columns from pasted CSV.Open →CSV row filterFilter pasted CSV rows by a keyword in a selected column.Open →CSV ↔ JSON converterConvert between CSV and JSON arrays, including quoted fields and line breaks.Open →CSV editorEdit CSV in a browser table with type-aware sorting, row and column controls, Undo, leading-zero preservation, and UTF-8 / Shift_JIS input.Open →CSV cleanerClean whitespace, blank rows, duplicates, and null markers, then remove, reorder, or rename columns with preview. Supports UTF-8 / Shift_JIS input.Open →CSV diff / compareCompare two CSV files by headers, rows, and cells and inspect additions, removals, and changes.Open →CSV column reorderReorder CSV columns, omit unwanted columns, and optionally keep unspecified columns at the end.Open →CSV bulk value replacerBulk-replace values in selected or all CSV columns using literal text or regular expressions.Open →CSV to Markdown tableConvert CSV to a Markdown table with alignment options and escaped pipe characters.Open →Markdown table to CSVParse a Markdown table into CSV and download the result.Open →CSV key joinJoin two CSV datasets by key using INNER, LEFT, or FULL join and export the result.Open →CSV transposeTranspose CSV rows and columns.Open →CSV group & aggregateGroup CSV by a key column and calculate count, sum, average, min, or max.Open →CSV row sorterSort CSV rows by a selected column as text or numbers in ascending or descending order.Open →CSV distinct values extractorExtract distinct values and occurrence counts from a selected CSV column.Open →CSV missing-value analyzerCount blank, NULL, NA, and other common missing-value markers by CSV column.Open →CSV numeric statisticsCalculate count, sum, mean, median, min, max, and standard deviation for a numeric CSV column.Open →CSV pivot tableCreate a simple SUM or COUNT pivot table from row, column, and value fields.Open →CSV column type profilerInfer integer, number, boolean, date, or string types for each CSV column and show blank rates.Open →CSV random samplerRandomly sample rows without replacement from CSV, with an optional deterministic seed.Open →CSV to SQL INSERT generatorGenerate SQL INSERT statements from CSV headers and rows.Open →CSV column renamerRename CSV headers in bulk using a mapping or a replacement header list.Open →CSV deduplicate by keyRemove duplicate CSV rows by selected key columns, keeping the first or last occurrence.Open →CSV split by column valueSplit a CSV into separate files for each distinct value in a selected column.Open →CSV header normalizerNormalize CSV headers to snake_case, camelCase, kebab-case, or safe identifier forms.Open →CSV outlier detectorDetect outliers in a numeric CSV column using IQR or z-score and extract flagged rows.Open →CSV percentile calculatorCalculate requested percentiles such as P25, median, P90, and P95 from a numeric CSV column.Open →CSV empty column removerDetect and remove CSV columns that are blank across all data rows.Open →Excel ⇄ CSV converterConvert a selected Excel sheet to CSV, or UTF-8 / Shift_JIS CSV to Excel, with preview, delimiter and BOM options, and leading-zero preservation.Open →CSV date column normalizerNormalize a CSV date column to YYYY-MM-DD and report rows that could not be converted.Open →CSV key uniqueness checkerCheck uniqueness of a CSV key column and list duplicate keys with row numbers.Open →CSV calculated column toolCalculate two numeric CSV columns and append the result as a new column.Open →CSV top N per groupExtract the top N rows by a numeric value within each CSV group.Open →CSV missing value fillerFill missing CSV values using a constant, mean, median, or forward fill.Open →
Related guides
Use these when you need the decision context around the tools.
CSV Complete Guide — Encoding, delimiters, quoting, and safe Excel workflowsReview decisions, failure points and workflow context.Read →CSV looks garbled in Excel—or everything lands in one column. Start here.Review decisions, failure points and workflow context.Read →UTF-8, Shift_JIS, and BOM — A practical encoding guide for CSV filesReview decisions, failure points and workflow context.Read →CSV delimiters, quotes, and newlines — Fix one-column imports and shifted rowsReview decisions, failure points and workflow context.Read →Why Excel changes CSV values — Leading zeros, long IDs, E notation, and datesReview decisions, failure points and workflow context.Read →
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Start from the job and follow the tools used in that workflow.
Related references
Keep the relevant formats and units close while you work.