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LidarKit

Convert LAZ to LAS

Decompress a LAZ point cloud back to uncompressed LAS. Runs on your machine — no upload, no size limit.

Drop your LAS or LAZ file here

or choose a file

LAS 1.0–1.4 · multi-gigabyte files welcome

No upload. Conversion runs in a Web Worker on your device — this app has no server component and no upload endpoint. How it works

When you actually need this

LAZ is the better format to store and share — it is lossless and typically five to ten times smaller. You generally need an uncompressed LAS for one reason: something in your toolchain refuses the compressed form. The common cases:

SoftwareReads LAZ?What to do
QGIS 3.18+YesNative via PDAL. If it fails, the build may lack PDAL support — convert to LAS.
QGIS below 3.18NoConvert to LAS, or upgrade.
ArcGIS ProYesVia LAS dataset tools. Convert LAS in Geoprocessing also does it, but needs a valid spatial reference.
ArcMapNoConvert to LAS first.
AutoCAD / Civil 3DPartlyReCap ingestion varies by version; uncompressed LAS is the reliable path.
CloudCompareYesNo conversion needed.

The problem to watch for: a lost coordinate system

The failure that costs people the most time is not a conversion that errors — it is one that succeeds and silently drops the coordinate reference system. Your points end up in the right relative positions and the wrong place on Earth, and you usually find out much later.

The CRS lives in the file's variable length records, as GeoTIFF keys or a WKT string. Several conversion routes rewrite the header and discard user VLRs along the way. This converter preserves the header, VLRs and EVLRs byte-for-byte, which is the specific reason it assembles the container itself instead of delegating to laz-perf's own file writer.

Other ways to do it

Worth knowing, because they are better than a browser tool for some jobs:

  • laszip — the reference tool, from the authors of the LAZ format. laszip -i input.laz -o output.las. Ideal if you are already on the command line.
  • PDAL — pdal translate input.laz output.las. The right choice for scripted or batch work, and for anything that needs reprojection or filtering in the same pass.
  • CloudCompare — open the LAZ, then File → Save as LAS. Convenient if you also want to look at the cloud.
  • This page — when you do not want to install anything, or the data cannot be uploaded to a third party, or the file is larger than an online converter will accept.

Frequently asked questions

Why do I need to convert LAZ to LAS at all?
Because some tools still cannot read compressed point clouds. LAZ is lossless and smaller, so it is the better format to keep — but older QGIS builds, several CAD import paths, and some proprietary survey packages only accept uncompressed LAS, and converting is faster than changing software.
Will converting LAZ to LAS change my data?
No. LAZ is a lossless compression of exactly the LAS byte layout, so decompression reproduces the original point records, header and coordinate reference system unchanged. The only thing that changes is the file size, which will grow by roughly five to ten times.
How long does it take?
Roughly a few seconds per hundred megabytes on a modern laptop, and it scales linearly with file size. Because the work happens on your own machine there is no queue and no upload time, which usually makes it faster end-to-end than a server-based converter for large files.
Can I convert several LAZ files at once?
Not yet — the converter handles one file at a time. For bulk work on many files, PDAL or LAStools on the command line is the right tool, since both can be scripted across a directory.

Going the other way? Compress LAS to LAZ — same tool, same guarantees.