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MCV Calculator

Calculate Moisture Condition Value from penetration readings per BS 1377-4. Includes TRL 644 / SHW Series 600 earthworks acceptability classification.

Last updated 23 June 2026

About this tool

Calculate the Moisture Condition Value (MCV) from penetration test readings per BS 1377-4. MCV is the standard UK test for assessing whether fill material is at a suitable moisture content for earthworks compaction.

Enter cumulative penetration readings — the tool finds the change point (where the increment drops below 5mm), calculates MCV, and classifies acceptability per TRL Report 644 and SHW Series 600.

Results are colour-coded: green (MCV ≥12, structural fill), amber (8–12, general fill), red (<8, unsuitable). No free MCV calculator exists online.

How to use this tool

1. Enter cumulative penetration readings — from the MCV test, comma or space separated. These are the total penetration after each set of blows.

2. Read the MCV and classification — the change point is found automatically.

Technical information

MCV = 10 × log₁₀(n)

Where n = number of blows at the change point (penetration increment < 5mm). Per BS 1377-4:1990.

Acceptability: MCV ≥8 for general fill (SHW Class 1/2), MCV ≥12 for structural/selected fill. Per TRL Report 644 and SHW Series 600 Clause 612.

Limitations

MCV indicates moisture condition only — it does not directly measure compaction achieved. A separate density test is needed to verify percent compaction.

The 5mm change point criterion is per BS 1377-4. Some specifications use different criteria — check the project specification.

MCV is most meaningful for cohesive and intermediate soils. It is less applicable to clean granular materials which may not show a clear change point.

Revision history

23 June 2026: Initial release

Disclaimer

This tool is provided for educational and general information purposes only. It is not a substitute for professional engineering advice, design or verification.

Diggy and its contributors are not licensed engineering consultants and no results generated by this tool should be used directly for construction, design or safety-critical decisions.

All values and outputs are based on published empirical correlations and should be independently checked and confirmed by a qualified geotechnical engineer before use.

By using this tool, you accept full responsibility for how you interpret and apply the information provided.

Spotted an error? Let us know.

Cumulative penetration readings (mm)

Enter cumulative penetration after each set of blows. Comma or space separated. The change point is where the increment drops below 5mm.

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