Free Online Soil Description Generator: BS 5930 and USCS Wording

Geotechnical
All tools
Report

Heading to the field? Install this site from your browser menu and this tool works with no signal. See how

Field description, BS 5930 style
USCS description, ASTM D2488 style
Group symbol

Diagram showing laboratory classification results being turned into a standard soil description sentence
Lab numbers go in, the sentence every borehole log needs comes out.

Why soil descriptions have a word order

Open any professional borehole log and the descriptions read like they were written by the same person: Stiff fissured grey slightly sandy CLAY. That is deliberate. BS 5930 and ASTM D2488 both fix the order of terms so that a reader can scan hundreds of strata and always find consistency in the same place, color in the same place, and the principal soil name in capitals at the end. A description in the wrong order is not wrong soil science, but it slows every reader down and it flags the log as amateur work.

What this generator does

You feed it the raw numbers a logger actually has: an SPT blow count, Atterberg limits for fine soils, grading observations for coarse soils, plus moisture, color, and structure from the trial pit or core. It applies the standard bands: N values map to consistency for clays and silts and to relative density for sands and gravels, the liquid limit sets the plasticity adjective, and the plasticity chart decides the USCS group symbol including the A line test. Out come two properly ordered sentences, one BS 5930 field style and one ASTM style with the group name, ready to paste into a log.

The bands behind the words

For fine soils, N below 2 reads very soft, 2 to 4 soft, 4 to 8 firm, 8 to 15 stiff, 15 to 30 very stiff, and above 30 hard. For coarse soils, N below 4 is very loose, 4 to 10 loose, 10 to 30 medium dense, 30 to 50 dense, and beyond 50 very dense. On the plasticity side, a liquid limit under 35 is low plasticity, up to 50 intermediate, up to 70 high, and beyond that very to extremely high. The group symbol follows the Casagrande chart: fine soils above the A line are clays, below it silts, with the dual CL/ML symbol in the narrow band where plasticity index sits between 4 and 7.

Honest limits

A generator cannot see the soil. It will not notice organic odor, shell fragments, rootlets, or the difference between fissured and sheared, and it applies SPT consistency bands that are correlations, not measurements. Treat the output as a correctly formatted starting sentence and edit it against what the sample in your hand actually shows. The standards also allow more nuance than any form: interbedding, partings, and inclusions still belong to the person holding the core.

Related Calculators and Reference