Free CSV Tools
A set of focused tools for the ways Excel and other spreadsheets mangle CSV files — plus a converter for switching delimiters and a cleaner for duplicate and blank rows. Every one runs entirely in your browser: your file is never uploaded, stored, or seen by anyone, and each tool keeps working offline once the page has loaded.
🔢 Fix scientific notation
Excel collapsed a UPC, EAN or account number into 8.85909E+11? Expand every value back to its full digit string using exact string math — no floating-point rounding, no precision loss.
0️⃣ Restore leading zeros
ZIP code 00501 became 501, or product code 0071589 lost its zero? Pick the column and the target width and the zeros come back across the whole file in one click.
🔤 Fix broken characters
café instead of café, “ instead of quotes? Reverse the encoding mistake (mojibake) automatically — even in files that were mis-encoded twice.
🛍️ Fix a Shopify product CSV
Shopify import failing, or barcodes, SKUs and titles arriving broken? Repairs all three Excel-caused problems at once — scientific-notation barcodes, dropped SKU zeros and garbled titles — ready to re-import.
Open the tool →🔄 CSV ⇆ TSV converter
Turn a comma file into tab-separated, or switch to semicolons or pipes for a fussy importer. Auto-detects the input delimiter, previews the table, and protects codes on the way out.
Open the tool →🧹 Clean a CSV
Remove duplicate rows, drop blank rows, trim stray spaces, and delete empty columns — in one pass, with a before/after preview. Your header stays put and nothing is uploaded.
Open the tool →🔎 Check CSV encoding
Drop a file and get a plain-English report: UTF-8, UTF-8 with BOM, UTF-16 or legacy ANSI — plus a mojibake warning and the matching fix. Reads the bytes locally; nothing is uploaded.
Open the tool →🔗 Merge CSV files
Combine several CSVs into one — monthly exports into a yearly file — stacked and aligned by column name, with an optional source-file column. Drop them all in; nothing is uploaded.
Open the tool →✂️ Split a large CSV
Too big for Excel to open (past 1,048,576 rows), or need it in chunks? Split by row count or into a set number of files, header repeated in each, download all as a zip. Nothing uploaded.
Open the tool →🔗 Join CSVs by a column
Match two files on a shared key column — a customer list to its orders by ID — the VLOOKUP job without the formula. Left or inner join, in your browser.
Open the tool →Which tool do I need?
Match the symptom in your file to the tool that fixes it:
| What you see in the file | Tool |
|---|---|
Numbers like 1.23E+12 where barcodes or IDs should be | Fix scientific notation |
| ZIP codes or SKUs missing their leading zeros | Restore leading zeros |
Accents shown as é, †or  | Fix broken characters |
| Right format, wrong delimiter (need tabs, semicolons or pipes) | CSV ⇆ TSV converter |
| Duplicate rows, blank rows, or stray spaces cluttering the file | CSV cleaner |
| Not sure if the file is UTF-8, has a BOM, or is ANSI | CSV encoding checker |
| Several CSVs to combine into one file | Merge CSV files |
| A file too big to open in Excel | Split a large CSV |
| Two files to match up by a shared ID / key column | Join CSVs by column |
| A Shopify import that fails, or barcodes/SKUs/titles broken after Excel | Fix a Shopify CSV |
| Every field crammed into one column, or a comma splitting a field | See the guides |
Want the background on why any of this happens and how to prevent it? Every problem has a full write-up in our CSV repair guides.
Comparing tools before you pay? See how we stack up as a free CSVFix alternative — no 50 KB limit and nothing uploaded.
Free broken-CSV sample files
Want to see a tool work before trusting it with your own data? Download one of these tiny, deliberately-broken files and drop it into the matching tool. They’re safe, made-up data — no real people or products — so reuse them freely for testing or teaching.
- sample-scientific-notation.csv — UPCs collapsed to
8.85909E+11→ fix it - sample-leading-zeros.csv — ZIP and ID codes missing their zeros → fix it
- sample-mojibake.csv — names full of
JoséandZürich→ fix it - sample-dates.csv — ambiguous
DD/MMdates → read the guide - sample-tab-separated.tsv — a tab-separated file → convert it
- sample-duplicate-rows.csv — duplicate and blank rows → clean it