To open a CSV in Excel online, upload the file to OneDrive and open it from there, or create a blank workbook in Excel for the web and pull the CSV in with Data, then Get Data, then Text/CSV. The second route lets you check column types before loading and leaves you with a proper XLSX workbook.
Two ways to open a CSV in Excel online from OneDrive
Excel online, also called Excel for the web, works on files stored in OneDrive or SharePoint, so upload the CSV first. Then either open the CSV file itself, or start a new workbook and import the CSV into it. The first is faster. The second gives you control over how columns are read.
Open the CSV directly. Upload it to OneDrive, then click it. You get no chance to set column types before the values are read. Microsoft's page on importing or exporting text and CSV files describes that behaviour for desktop Excel: the program uses its current default data format settings to decide how to read each column.
Import into a blank workbook. Create a new blank workbook in OneDrive, which is saved as XLSX from the start, then use Get Data to bring the CSV in. This is the better choice for statement files, because it lets you set a column to text before account numbers lose their leading zeros.
Importing a CSV into a blank Excel online workbook with Get Data
Importing a CSV with Get Data in Excel online runs it through Power Query, which shows a preview and lets you change column types before loading. Microsoft's guide to Power Query in Excel for the web lists Text/CSV among the sources, starting from Data, then Get Data.
The steps, with example settings for a bank statement CSV:
- In OneDrive, create a new blank Excel workbook and give it a name, for example "March statement".
- Go to Data, then Get Data.
- In Choose data source, pick Text/CSV and point it at the CSV.
- Connect, then click Next and check the preview.
- Click Transform data to open the Power Query editor.
- Set the date column's type to Date, the amount and balance columns to Decimal number, and any reference or check number column to Text.
- Click Close & Load. The data lands in a table on a new sheet.
The same page notes that your browser needs third-party cookies enabled for some Power Query features. If the Get Data button does nothing in a private window, that is the first thing to check.
What can't Excel online do with a CSV file?
Excel online cannot open a CSV that lives only on your computer, and some of its import tools depend on your Microsoft 365 plan. Microsoft's Power Query page says viewing and refreshing queries is available to all Microsoft 365 subscribers, while additional functionality is limited to business and enterprise plans. A free account may see fewer options.
Practical limits to plan around:
- Cloud storage first. The file has to be in OneDrive or SharePoint. A CSV in your Downloads folder must be uploaded before Excel for the web can reach it.
- Plan-dependent import tools. If the Get Data menu offers less than the steps above, your account type is the likely reason.
- Cookies and private windows. Blocked third-party cookies stop parts of Power Query from working.
- Macros. VBA macros do not run in the browser, so a workbook that relies on them to clean an import has to open in desktop Excel.
For a CSV that came from a scanned statement or a screenshot, the work starts before Excel. Getting a PDF image into Excel covers the OCR step that turns the picture into rows.
How do you keep the Excel online result as XLSX?
To keep an Excel online result as XLSX, work in a workbook that is already XLSX, such as the blank workbook used for the Get Data import. If you opened the CSV itself and formatted it, save a copy in Excel format from the File menu. A CSV cannot store formatting, formulas or more than one sheet.
This matters more than it seems. Column widths, number formats, a frozen header row and a total formula all disappear if the file stays CSV. They look fine while the tab is open and are gone the next time someone opens the file.
Keep two files: the original CSV, untouched, as the raw export, and an XLSX workbook as the working copy. If you need to send a CSV on to another program later, use File, then Export in Excel for the web to download the current sheet as CSV.
CSV files too large for Excel online
A CSV with more rows than an Excel worksheet holds cannot open whole in Excel online. Microsoft's Excel specifications and limits set a worksheet at 1,048,576 rows by 16,384 columns. Rows beyond that limit do not load, and a very large file may also be slow to open in a browser.
A year of statement transactions is nowhere near that limit. The edge case is an export that combines many accounts or many years. For those:
- Split the CSV by year or account before uploading.
- Summarise in Power Query, if your plan offers it, with a Group By step, so totals per month reach the sheet instead of every row.
- Filter early in the Power Query editor so only the rows you need reach the sheet.
Google Sheets has a different kind of ceiling, counted in cells rather than rows. The Google Sheets cell limit explains how to work out whether a file fits, and why Google Sheets slows down with large data covers what happens before you reach it.
FastBankConvert is being built to produce statement CSV and Excel files with each field in its own column, ready for either program. It is getting ready to open; you can join at Get started.