CSV Cleaner
Clean messy CSV files — trim whitespace, remove empty and duplicate rows, fix quoting, and normalize formatting.
100% in your browser — nothing uploadedRemove Duplicate Rows, Trim Whitespace, and Fix CSV Formatting Online
About the CSV Cleaner
This CSV cleaner fixes the most common problems in messy CSV files with one click. It trims leading and trailing whitespace from every cell, removes completely empty rows, deduplicates identical rows, strips unnecessary quoting, and normalizes line endings — all without uploading your data anywhere.
The tool parses CSV properly (RFC 4180 compliant), handling quoted fields, embedded commas, and escaped quotes correctly. It auto-detects the delimiter and works with comma, semicolon, tab, and pipe-separated files. The cleaned output uses minimal quoting — cells are only quoted when they contain a delimiter, newline, or double-quote.
Common CSV problems this tool fixes
Exported CSV files from spreadsheets, CRMs, and databases often have formatting issues that break downstream tools. This cleaner handles the most frequent ones.
| Problem | What happens | How the cleaner fixes it |
|---|---|---|
| Trailing spaces | Values like " Austin " don't match "Austin" in lookups | Trim whitespace strips leading and trailing spaces from every cell |
| Empty rows | Blank lines between data rows cause import errors | Remove empty rows deletes rows where all cells are empty |
| Duplicate rows | Copy-paste errors or repeated exports create identical rows | Remove duplicates keeps the first occurrence and drops repeats |
| Inconsistent quoting | Some cells wrapped in quotes, others not — or double-doubled quotes | Standardize quoting applies minimal RFC 4180-compliant quoting |
| BOM character | The invisible at the start breaks parsers and shows as garbled text | Automatically stripped during parsing |
Cleaning CSV in Excel, Google Sheets, and the command line
You can clean CSV files in spreadsheets or the command line, but each approach has trade-offs. This tool handles all the common cases without any setup.
Excel / Google Sheets:
Trim: =TRIM(A2) — but only trims spaces, not tabs
Deduplicate: Data → Remove Duplicates (Excel) or
Data → Data cleanup → Remove duplicates (Sheets)
# Command line (Linux/Mac):
# Remove empty lines:
sed "/^[,]*$/d" dirty.csv > clean.csv
# Remove duplicate lines (preserving order):
awk "!seen[$0]++" dirty.csv > clean.csv
# Trim whitespace in cells (harder — needs a proper CSV parser):
python3 -c "import csv,sys; w=csv.writer(sys.stdout); [w.writerow([c.strip() for c in r]) for r in csv.reader(open('dirty.csv'))]"FAQ
What does the CSV cleaner do exactly?
It performs five cleaning operations: trimming whitespace from cells, removing rows where every cell is empty, removing duplicate rows (keeping the first occurrence), standardizing quoting (only quoting cells that need it), and normalizing line endings. Each operation can be toggled individually.
Does it change the order of my rows?
No. The cleaner preserves the original row order. When removing duplicates, it keeps the first occurrence and removes subsequent identical rows. The header row (if enabled) is never removed even if duplicated.
Can it handle large CSV files?
Yes, because everything runs in your browser with no upload. The practical limit is your device's available memory. Files with tens of thousands of rows process in under a second on modern hardware.