About Excel Data Analyzer
This Excel data analyzer opens .xlsx and .xls workbooks in your browser. It starts on a sample two-sheet workbook so you can see the result at once, then reads your own file when you drop it, and profiles each column of the sheet you pick. It is free, needs no sign-up and runs in your browser, so nothing you enter is uploaded.
The workbook is read in a background worker with SheetJS, which loads only when you open an Excel file. If the workbook has several sheets, a Sheet list appears and each sheet is profiled on its own. The first non-empty row of the sheet is the header row, blank rows are skipped, and the file is never uploaded. You can also copy a range in Excel and paste it into the text box, which Excel copies as tab-separated text.
You see the values saved in the file. Formulas are not recalculated, a cell shown as 15% arrives as 0.15, and dates arrive as ISO text such as 2026-03-04. Merged cells, charts, pivot tables and formatting do not carry over, and password-protected workbooks cannot be opened. A column is numeric when at least 95 percent of its non-missing values are numbers, so a stray TBD or a typo is listed instead of ruining the statistics.
How to use Excel Data Analyzer
- Drop a file onto the box, tap it to choose one, or paste a copied file. CSV, TSV, TXT, XLSX and XLS files up to 20 MB are accepted. To paste text instead, use the text box below it.
- For a workbook with several sheets, choose the sheet from the Sheet list that appears.
- Read the Overview: rows, columns, missing values, the delimiter and any columns that held stray values.
- Open Summary for per-column statistics, then Profile for types, percentage missing, distributions and the stray values.
- Open Correlation to see how the numeric columns move together, with blue for positive and red for negative.
- Open Preview to read the rows, 50 per page. Type in the filter box to keep matching rows, and press a column header to sort.
- Open Chart, pick a chart type and a column (two for a scatter plot), or press Open Chart Maker for more chart types.
- Press the download button in Summary to save the column statistics as a CSV file.
Features
- Open .csv, .tsv, .txt, .xlsx and .xls files up to 20 MB, or paste a file or text.
- Parsing runs in a Web Worker for files and pastes, never on every keystroke. The paste box waits half a second after you stop typing.
- Automatic delimiter detection among comma, semicolon, tab and pipe, with quoted fields and a leading byte-order mark handled.
- Excel support through SheetJS, loaded only when a workbook is opened, with a sheet picker.
- Columns are tracked by position, so two columns with the same header stay separate. The second one is shown as "name (2)".
- Majority-type inference: a column is numeric when 95 percent or more of its non-missing values are numbers, and a date column on the same rule. Stray values are listed.
- Missing values recognised as empty cells, NA, N/A, NaN, null, none, nil, a single or double dash and #N/A, in any letter case.
- Per-column count, missing, unique, mean, median, quartiles, minimum, maximum and sample standard deviation.
- Minimum and maximum are found with a loop, so columns of hundreds of thousands of values are safe.
- Pearson correlation matrix of the numeric columns (the first 30 when there are more), using only rows where both values are present.
- Paged preview, 50 rows per page, with a filter and sortable headers, inside a scroll area that works on a phone.
- Chart builder: bar chart of counts, histogram and scatter plot, plus a link to Chart Maker.
- Download of the per-column summary as a CSV file.
Worked examples
The sample workbook, Sales sheet: 20 rows of date, region, units and revenue gives units: number, 19 numbers, mean 50.74, 1 stray value (TBD) left out. revenue: mean 645.6, min 480, max 789. date: date. region: 4 unique.
The TBD in the units column is 1 of 20 values, which is 95 percent numeric, so the column stays numeric.
The sample workbook, Staff sheet, after choosing it in the Sheet list gives age: mean 31.83, median 30.5. salary: 5 values, 1 missing, mean 4640. team: 3 unique.
Good to know
About the sample workbook
The page opens on a small workbook built into it, with a Sales and a Staff sheet, so the sheet picker and the stray-value report can be seen without a file. It is not a file you can download. Drop your own workbook to replace it.
Privacy: how it works
- Files are read by your browser and parsed by JavaScript in a worker on this page. The contents are not sent to Ulkaa or to any other server. The Excel reader is part of this site and loads from it, not from a third party, and only when you open a workbook.
- Nothing is stored. Reloading the page clears everything. The summary CSV is created on your device when you press the download button.
Tips
- If a column you expected to be numeric shows as text, open Profile and read its stray values. A currency symbol, a decimal comma or a word is usually the cause.
- Check the missing count before looking at averages. A mean computed from only 60 percent of the rows can mislead.
- A correlation matrix only covers numeric columns. Encode a yes or no column as 1 and 0 first if you want it included.
- Quote any field that contains your delimiter, such as "1,200" in a comma file, so the row keeps its column count.
- For a very large file, open it instead of pasting it. The paste box is meant for small pastes.
- Delimiter detection looks at the first five lines. Make sure they use the same separator as the rest.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial and no credit card. Ulkaa Tool does the work with your own device, so there is no server bill to pass on to you.
Do I need an account?
No. There is no sign-up and no login. Open the page and use it. An Ulkaa account is not needed for anything on this tool.
Does it run in my browser?
Yes. Your data are processed by code running in your browser tab, on your own device.
Is my data uploaded?
No. Your data are never sent to Ulkaa or to anyone else. You can check this yourself by watching the Network tab in your browser developer tools while you use the tool.
Can I upload an Excel file?
Yes, an .xlsx or .xls file of up to 20 MB. It is read on your device, not uploaded to a server.
Are formulas and multiple sheets supported?
Multiple sheets, yes: choose one from the Sheet list. Formulas are not recalculated, so a formula cell shows the last value Excel saved in the file.
Why does my percentage show as 0.15?
The tool reads the number stored in the cell. A cell formatted as 15% holds 0.15, and the display format is not applied.
Can I still paste a range from Excel?
Yes. Copy the cells, including the header row, and paste them into the text box. Excel copies them as tab-separated text, and the delimiter is detected automatically.
More CSV, Excel and Data Analyzer pages
- CSV, Excel and Data AnalyzerOpen a CSV, TSV or Excel file, or paste text, and profile every column: types, missing values, statistics, charts and correlations.
- CSV Analyzer OnlinePer-column statistics for a CSV file, in the Summary view.
- CSV Viewer OnlineLook at your CSV as a table, with a filter box and sortable columns.
- Excel Viewer OnlineOpen an Excel file, choose a sheet and read it as a table.
- Correlation Matrix OnlineA Pearson correlation matrix of every numeric column in your data.
- Data Profiling Tool OnlineA column-by-column profile of a CSV, an Excel sheet or a pasted table.