Guides

How to clean CSV and Excel files with CleanMySheet. Every guide is a real workflow in the browser — not a keyword dump.

• Clean a CSV online without uploading it

  Clean CSV files in your browser: trim spaces, fix dates, remove duplicates, split names, and export. CleanMySheet never uploads your sheet in Strict mode.

• Clean Excel (XLSX) files in the browser

  Fix Excel spreadsheets locally: serial dates, accounting negatives, duplicates, multi-sheet workbooks. CleanMySheet parses XLSX in your browser.

• Remove duplicate rows from a spreadsheet

  Delete exact duplicate rows and review fuzzy matches (John Smith vs Jon Smith). CleanMySheet keeps the first row and never auto-deletes near-duplicates.

• Find near-duplicate rows (fuzzy matching)

  Flag similar spreadsheet rows with Levenshtein matching. Review John Smith vs Jon Smith before anything is deleted.

• Standardize mixed date formats in a spreadsheet

  Convert 03/14/22, March 14 2022, and Excel serials to YYYY-MM-DD, DD/MM/YYYY, or MM/DD/YYYY. Runs in the browser.

• Split names in a CSV (Last, First and First Last)

  Split Full Name into First Name and Last Name. Handles Last, First and First M Last. Only name columns are touched.

• Format phone numbers in CSV or Excel

  Normalize phones to (555) 123-4567 or 555-123-4567. International numbers that start with + keep the plus and digits.

• Format emails in a spreadsheet (trim + lowercase)

  Lowercase and trim email columns, then optionally extract the domain for segmentation. Runs locally.

• Trim whitespace in spreadsheet cells

  Remove leading, trailing, and doubled internal spaces from CSV/Excel columns. Unify N/A and NULL separately.

• Turn N/A, NULL, and dashes into blank cells

  Standardize empty placeholders in spreadsheets so analysis and pivots treat missing data consistently.

• Drop empty rows and columns from a spreadsheet

  Remove entirely blank rows and columns after unifying placeholders. Local, reversible.

• Clean CRM contacts from a spreadsheet export

  CRM Cleanup preset: trim, unify empties, split names, format phones and emails, remove exact duplicates — in the browser.

• Clean QuickBooks and finance CSV/Excel exports

  Convert accounting negatives, strip currency symbols, standardize dates. Finance preset runs locally.

• Convert European number format to 1234.56

  Parse 1.234,56 and 12,50 into real numbers for analysis. In-browser, reversible.

• Clean survey spreadsheet exports

  Unify empties, trim, map Y/1/true to Yes, deduplicate. Built for Google Forms and Typeform CSV.

• Map Y, 1, true → Yes in a spreadsheet

  Normalize boolean-like survey and CRM fields to Yes/No.

• Split a US address column in a CSV

  Parse “123 Main St, Springfield, IL 62704” into street, city, state, zip when the pattern matches.

• Clean HRIS and employee roster exports

  Format names, phones, emails, and addresses. SSN-like columns are locked, never masked or uploaded.

• Clean spreadsheets without uploading your data

  Client-side CSV/Excel cleaner. Strict mode default: no column samples leave the browser. Built for India and global teams who cannot send PII to a cloud model.

• Why a rule-based cleaner beats ChatGPT for CSV cleanup

  Compare CleanMySheet to pasting data into ChatGPT: audit trail, no hallucinations, privacy, instant preview.

• Fill missing values from the row above

  Forward-fill blank spreadsheet cells from the previous row. Common for exported grouped reports.

• Clean a HubSpot contact or company CSV

  Trim, split names, format phones and emails, and dedupe HubSpot exports in the browser before re-import.

• Clean Salesforce CSV before Data Loader

  Normalize Salesforce lead and contact CSVs: dates, phones, emails, duplicates. Local processing.

• Download Google Sheets as CSV and clean it locally

  File → Download → CSV from Google Sheets, then clean duplicates, dates, and phones in the browser.

• Turn a messy Excel file into a clean CSV

  Parse XLS/XLSX in the browser, clean dates and numbers, export CSV. No desktop Excel required.