Version 9.1 carries forward the core analytical capabilities, including:

). This is critical for characterizing poorly sorted or highly skewed natural environments, such as riverbeds, sand dunes, and glacial tills. Calculated Statistics at a Glance

These calculations are performed both arithmetically and geometrically, using both metric and phi units. The software employs both the method of moments and the graphical methods of Folk and Ward (1957) to provide a comprehensive statistical analysis.

Since GRADISTAT runs on Excel macros, make sure to "Enable Content" or "Enable Macros" when you first open the .xlsm file, otherwise the calculation buttons won't trigger.

While version 9.1 is not the absolute latest (with versions 8.0 and later being more compatible with modern Excel), you can obtain version 8.0 or similar from the official source. Many researchers using v9.1 in their work accessed it through this same channel. Exercise caution when using third-party websites for downloads, as they may contain outdated or altered versions.

Since GRADISTAT is provided as-is without formal customer support, here are some tips for getting help:

Your software is now ready to use.

You can find documentation and download links for authorized versions at:

Manually calculating grain metrics for dozens of sediment samples is notoriously time-consuming. GRADISTAT solves this bottleneck by providing rapid, systematic processing—handling up to while generating professional, publication-ready tabular and graphical outputs.

Written originally by Dr. Simon J. Blott and published alongside Professor Kenneth Pye, this tool has become a foundational standard in geomorphology, geology, and environmental science. By running seamlessly inside standard spreadsheet software, it eliminates the need for expensive, proprietary statistical software while providing publication-ready charts and sediment classification data. What is GRADISTAT and Why is it Used?

: Including X-ray sedigraph and Coulter counters.

Version 9.1 of GRADISTAT represents a significant point in the software's evolution. While the original version was developed for Microsoft Excel 1997 and 2000, and version 8.0 was released in December 2010 for use with Excel up to 2010, version 9.1 was widely used in scientific research during the late 2010s and early 2020s. For instance, a 2024 dataset publication on PANGAEA notes: "The subsequent analysis of grain size statistics was done in GRADISTAT v9.1 (Blott & Pye, 2001)". This citation by researchers confirms the ongoing relevance and trust in this particular version.

The program was created to solve a common problem: grain size analysis is essential for classifying sedimentary environments, but calculating statistical parameters for many samples is extremely time-consuming. GradiStat automates this entire process, allowing researchers to process approximately 50 samples per hour.