Excel to CSV converter: any sheet, UTF-8, dates kept as dates
In short: Reads every sheet of an .xlsx, .xlsm or .ods file (or cells pasted from Excel), lets you pick one, and writes a UTF-8 CSV with comma, semicolon or tab delimiters. Date cells become YYYY-MM-DD, leading zeros and long IDs are kept, blank rows dropped. Runs in your browser. Limit: Numbers lose their display format: percentages, currency signs and thousands separators aren't written, only the stored value.
Upload the workbook, pick the sheet and download the CSV. The file is UTF-8, so accents and non-Latin names survive; values are written as stored, so 02108 keeps its zero and a 16-digit ID keeps every digit; and date cells come out as 2026-11-03 instead of a serial number like 46329. Everything runs in your browser.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. See pricing
Sample result
Sheet Leads: 3 rows, 5 columns, 3 dates written as YYYY-MM-DD, 3 email addresses.
- Rows
- 3
- Sheets in workbook
- 2
- Dates converted
- 3
What this means for you
The CSV is UTF-8 with 02108 kept as 02108, ready for a sending tool or CRM import.
- Pick any sheet
- Dates as YYYY-MM-DD
- Leading zeros kept
- Comma, semicolon or tab
- Excel
- CSV
- UTF-8
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
Also in: Português (Brasil) · Español
How do I check the email addresses in the sheet?
- Download the CSV.
- Upload it at /verify. Every address gets a live mailbox check, and valid, risky and invalid download as separate files. The first 100 email checks are free with a Google sign-in, no card.
- Import the valid file into your sending tool or CRM.
How do I convert Excel to CSV?
- Upload an .xlsx, .xlsm or .ods file (up to 25 MB), or paste cells copied from Excel or Google Sheets.
- If the workbook has more than one sheet, choose the one to convert.
- Pick the delimiter: comma for most tools, semicolon where the importer expects European-style files, tab for TSV. Blank rows are dropped and values trimmed unless you untick those options.
- Check the preview and download the CSV. Add the UTF-8 BOM only if the file will be opened in Excel again.
Example
- You enter
- A two-sheet .xlsx (Leads and Opt-outs) whose Leads sheet has email, first_name, zip (
02108stored as text), a signed_up date column and a notes column with quotes and a comma, plus one blank row. - You get
- Leads chosen: 3 rows and 5 columns, the blank row dropped, signed_up written as
2026-11-03instead of the serial 46329,02108kept, and the quoted note escaped as RFC 4180 describes. 3 email addresses found for the next step. - Limits
- Runs in your browser; an uploaded workbook can be up to 25 MB. No .xls or password-protected files.
Why not just use Save As CSV in Excel?
It works, with three catches people run into before an import. Excel saves only the active sheet, which Microsoft's own help points out, so a workbook with a Leads tab and an Opt-outs tab needs two saves. The plain "CSV (Comma delimited)" option is not UTF-8, so names like José or Zoë can turn into ? or é; you have to pick "CSV UTF-8" instead. And Excel writes what the cell displays, so a date formatted as 3/11/26 is saved in your computer's regional format, which an importer in another country can read as 11 March or 3 November.
This converter writes UTF-8 every time, works on any sheet you pick, and turns date cells into ISO dates (YYYY-MM-DD, with HH:MM:SS when the cell holds a time), which every CRM, sequencer and verifier reads the same way.
How are dates, numbers and formulas converted?
Excel stores a date as a serial number of days, so 3 November 2026 is 46329 in the default 1900 date system. A cell whose number format is a date or time is converted from that serial; workbooks using the 1904 date system, which Microsoft says is 1,462 days apart, are detected from the file and converted correctly.
Other numbers are written as stored, without the cell's display format: 0.25 rather than 25%, 1234.5 rather than $1,234.50. Text cells, including zip codes and phone numbers saved as text, are copied exactly, so their leading zeros stay. Formulas are written as the result Excel last saved with the file, not the formula itself. TRUE and FALSE cells become the words TRUE and FALSE.
Comma or semicolon: which delimiter should I pick?
Comma, unless you know the tool wants something else. Sending tools, CRMs and verifiers built for an English-language market read comma-separated files. Excel in countries that write decimals with a comma (much of Europe and South America) saves and expects semicolons, so pick semicolon for a file that colleagues there will open in Excel. Tab-separated files are the safest when values themselves contain commas and the importer doesn't handle quotes.
Values that contain the delimiter, quotes or line breaks are wrapped in double quotes as RFC 4180 describes, so a note like Asked for "pricing", twice survives either way.
Is this better than Save As CSV or Google Sheets?
| This tool | Excel Save As CSV UTF-8 | Google Sheets Download CSV | |
|---|---|---|---|
| Which sheet | Any, pick from a list | Only the active sheet | Only the open sheet |
| Encoding | UTF-8, optional BOM | UTF-8 with BOM | UTF-8 |
| Dates | YYYY-MM-DD | As displayed, in your regional format | As displayed |
| Delimiter | Comma, semicolon or tab | Set by your regional settings | Comma |
| Blank rows | Dropped (optional) | Kept | Kept |
| File leaves your computer | No | No | Uploaded to Google Drive first |
Who uses this tool, and for what?
- Cold emailers
- Turn a lead sheet someone sent as .xlsx into a CSV that Instantly, Smartlead or lemlist will import.
- Marketing ops
- Export one tab of a shared workbook to a UTF-8 CSV for a CRM or ESP import, with dates the importer reads correctly.
- Agencies
- Convert a client's multi-tab workbook sheet by sheet, without opening it in Excel or uploading it to a cloud drive.
- Sales teams
- Get a clean CSV of event or trade-show contacts out of a spreadsheet before checking the addresses.
What can’t this tool tell you?
- Numbers lose their display format: percentages, currency signs and thousands separators aren't written, only the stored value.
- Formulas give the result saved in the file. If the workbook was saved without recalculating, that result can be out of date.
- Old .xls (Excel 97-2003) and password-protected workbooks can't be read.
- Merged cells give their value to the first cell only; the rest are blank.
- It converts the file; it doesn't check whether the email addresses in it work. That needs a mailbox check.
Common questions
- How do I convert an .xlsx to CSV without Excel?
- Upload it here and download the CSV. The conversion runs in your browser, so you don't need Excel, Numbers or a Google account.
- Can it convert every sheet at once?
- One sheet per download. Pick a sheet from the list, download it, then pick the next; each file is named after its sheet.
- Why do my dates show as numbers like 46329 elsewhere?
- That's Excel's serial date. This tool reads the cell's date format and writes
2026-11-03instead. A date typed into a cell formatted as text stays exactly as typed. - Does it work with old .xls files?
- No. Excel 97-2003 .xls is a different binary format. Open it in Excel and Save As .xlsx, then convert that.
- What about password-protected workbooks?
- They're encrypted, so they can't be read without the password. Remove the password in Excel first.
- Should I add the BOM?
- Only if the CSV will be opened in Excel by double-click, which uses the BOM to recognise UTF-8. Most importers don't need it, and a few show it as stray characters at the start of the first column name.
- Is my file uploaded?
- No. The workbook is unzipped and read in your browser, and the CSV is built there.
Sources
A tidy list can still be full of dead addresses.
Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.
- Upload the cleaned file as it is: CSVs up to 100,000 rows
- A real SMTP mailbox check on every row, with catch-all detection
- Small list? Starter at $9/mo covers 2,500 emails a month, cancel anytime
Plans from $9 a month, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.