Atterberg Limits Calculator (PI, LI, CI)
Plasticity, liquidity and consistency indices — plus the A-line classification.
LI is the drama gauge: LI near 1 means the ground sits at its liquid limit — sensitive clays (Norwegian quick clays) carry LI > 1 and liquefy when disturbed. PI > 25–30 warns of shrink-swell.
Formula
Atterberg Limits Calculator (PI, LI, CI) is a free atterberg limits for geotechnical engineers and foundation designers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Atterberg Limits Calculator (PI, LI, CI)
Plasticity, liquidity and consistency indices — plus the A-line classification. The calculation implements PI = LL−PL; LI = (w−PL)/PI; A-line: PI = 0.73(LL−20) (Casagrande chart; IS 1498). LI is the drama gauge: LI near 1 means the ground sits at its liquid limit — sensitive clays (Norwegian quick clays) carry LI > 1 and liquefy when disturbed. PI > 25–30 warns of shrink-swell.
How to use Atterberg Limits Calculator (PI, LI, CI)
- 1Enter Liquid limit LL in %.
- 2Enter Plastic limit PL in %.
- 3Enter Natural water content in %.
- 4Read Plasticity index PI, Liquidity index LI, A-line PI at this LL instantly — no submit button needed.
Why use Atterberg Limits Calculator (PI, LI, CI)?
- ✓Implements the standard formula — PI = LL−PL; LI = (w−PL)/PI; A-line: PI = 0.73(LL−20)
- ✓Reference cited on-page: Casagrande chart; IS 1498
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Atterberg Limits Calculator (PI, LI, CI) use?+
It computes PI = LL−PL; LI = (w−PL)/PI; A-line: PI = 0.73(LL−20), per Casagrande chart; IS 1498. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
LI is the drama gauge: LI near 1 means the ground sits at its liquid limit — sensitive clays (Norwegian quick clays) carry LI > 1 and liquefy when disturbed. PI > 25–30 warns of shrink-swell.
Can this replace a soil investigation?+
No calculator replaces boreholes and lab tests — but with investigated parameters in hand, this gives you the standard-method result instantly, with the formula shown so reviewers can check it.
Is the Atterberg Limits Calculator (PI, LI, CI) free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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