Free Online LAS to CSV Converter: Well Log Files to Spreadsheet

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The converter reads the curve section for column names, the well section for the null value, and the ASCII section for the data, then writes a clean CSV. Null readings become empty cells so spreadsheets and plotting tools treat them as gaps instead of huge negative spikes.

The most requested conversion in petrophysics

Every wireline log on earth ships as a LAS file, and almost nothing outside specialist petrophysics software opens one. The converter above fixes that in seconds: paste the content or load the file, and the curve section becomes column names, the ASCII section becomes rows, and the null value declared in the well section becomes empty cells instead of the notorious spikes at minus 999.25. The CSV downloads instantly and opens in any spreadsheet, plotting tool, or script.

A LAS well log file with version, well, curve, and ASCII sections being converted into a clean CSV table with named columns and blanked null values
The oilfield log format becomes rows and columns any software can open.

Your file never leaves your machine: the parsing happens entirely in the browser, which matters when logs are confidential, and it usually is exactly that clause in the data agreement.

What the converter handles

  • LAS 2.0 files with one data line per depth, which covers the overwhelming majority of files in circulation.
  • Any number of curves: the curve section defines the columns, whatever they are.
  • The null value is read from the file rather than assumed, so files using different conventions convert correctly.
  • Null blanking is optional: keep the raw values when your workflow expects them.

Where the CSV goes next

Straight into a spreadsheet for quick crossplots, into Python or R for analysis, or into the other tools on this site: the LAS viewer for petrophysics, the contour app for mapping formation tops, and Report Studio when the work becomes a deliverable.

Related Calculators and Reference

Common Questions

How do I convert a LAS file to CSV?

Paste the LAS content or load the file into the converter at the top of this page. Curve names become column headers, data rows become CSV rows, and the download is one click, all in your browser.

What is the null value in a LAS file?

A placeholder, usually minus 999.25, marking depths where a curve was not recorded. The converter reads the declared null from the file and can blank those cells so they plot as gaps instead of spikes.

Is my well log uploaded anywhere?

No. Parsing happens locally in the browser, which matters because log data is usually confidential.