You tap the attachment. iOS thinks about it, and then shows you this:
order_id,customer,region,amount,status
10041,"Nguyen, Minh",APAC,1290.00,shipped
10042,"O'Brien, S.",EMEA,845.50,pending
That is not a preview failing. That is iOS doing exactly what it was asked:
a .csv is a plain text file, Quick Look renders plain text, and a text file
with commas in it looks like a text file with commas in it. There is no
spreadsheet on an iPhone unless you put one there.
Here is every route to actually reading the thing, in rough order of how little effort each takes.
The fast answer
- Small file, already have Numbers: long-press the file in Files → Share → Numbers. Free, built in, fine up to a few tens of thousands of rows.
- Small file, no apps at all: upload it to Google Sheets in Safari.
- Large file, or you need it now: a CSV app that opens the file directly from Files, with no import or upload step.
- You only need to see the header row: Quick Look is already showing it. Don't install anything.
Why iOS shows raw text
Three things about iOS conspire here, and none of them are bugs:
.csvhas no system-level owner. iOS ships no application that claims the type, so Quick Look falls back to its plain-text renderer.- Quick Look truncates. The preview reads the beginning of the file and stops. On a large export you are seeing the first screen, not the file.
- Mail previews are read-only and sandboxed. Even when a CSV opens in Mail, you are looking at a copy the app will throw away. Save it to Files first — long-press the attachment, Save to Files — before you do anything else.
The practical consequence: whatever you do next, do it on a file that lives in Files or iCloud Drive, not on an attachment still inside Mail.
Route 1: Numbers
Apple's spreadsheet is a free download and handles CSV import properly, which makes it the right first try for an ordinary file.
Files → long-press the CSV → Share → Numbers. It converts the file into a Numbers document and opens it.
That last sentence is the catch, and it is worth being precise about:
- The result is a
.numbersfile, not your CSV. Edits go into the copy. To get a CSV back out you have to Export → CSV, which produces a new file rather than saving over the original. - Numbers caps at 1,000,000 rows and 1,000 columns, and gets slow long before that. A 200,000-row file will import, eventually, and then scroll like treacle.
- Import guesses at types. Leading zeros in postcodes and product codes get eaten, and long numeric IDs turn into scientific notation.
For a 2,000-row expense export, none of that matters and Numbers is the correct answer. For anything you have to hand back unchanged, it is the wrong tool — see the conversion caveats in CSV vs XLSX.
Route 2: Google Sheets or Excel
Both exist on iOS, both are free to a point, and both work the same way: the file goes up to a server, gets converted, and comes back as a spreadsheet document.
- Google Sheets needs the file in Google Drive first, then Open with → Google Sheets. Its ceiling is 10 million cells — a 30-column export runs out at roughly 330,000 rows.
- Excel for iOS opens CSVs directly but is heavily reduced compared with the desktop version, and editing needs a Microsoft 365 subscription on any iPad over 10.1 inches.
The real cost of both is the upload. On cellular, with a 150MB export, this is the slowest route on this page by a wide margin — and it means the file leaves the device, which for a customer list is a decision rather than a detail.
Route 3: a CSV app
The case none of the above serves well is the common one: the file is big, it is already on the phone, and you want to look inside it now without converting it into something else first.
An app that reads the CSV in place skips both the import step and the upload.
Opens the file straight from Files and keeps it a CSV: SQL queries, visual filters, charts, an AI assistant you can ask in plain language, and PDF export.
What it doesReading is one job; changing rows and handing the file back is another. The thing to check before you trust any iOS app with the second one is whether it loaded the whole file — several mobile CSV apps read the first few thousand rows to stay responsive, and an app that loaded part of your file will write part of it back.
Spreadsheet-style editing on iPhone and iPad — Excel-style sort and filter, formula columns, undo and redo — with every row preserved on save, including in the free version.
What it doesRoute 4: don't open it on the phone at all
Worth saying plainly, because the internet rarely does: if the file is 800MB and you need to run a real analysis, AirDrop it to a Mac and use DuckDB. A phone is the right tool when the file is on the phone and the answer is needed now. It is not the right tool for a full day's work on a dataset.
The desktop routes — DuckDB, Power Query, splitting the file — are covered in how to open a large CSV file that Excel won't open.
If the file opens but looks wrong
Three failures account for nearly all of them on iOS:
| What you see | Cause |
|---|---|
| Every row crammed into one column | Semicolon or tab delimiter, not comma |
é where é should be | The file is UTF-8, read as Latin-1 |
order_id in the first header | A byte-order mark on the first line |
| Rows splitting in half mid-record | Unescaped quotes or newlines inside fields |
None of those are iOS's fault and none require a different phone. They are covered in how to fix a broken or malformed CSV file.
One habit worth keeping
Duplicate the file before you edit it. In Files: long-press → Duplicate. It takes two seconds, and it is the difference between "the app truncated my export" being a disaster and being a shrug.