Uniformity Coefficient (Cu) & Curvature (Cc) Calculator
Cu and Cc from D10, D30 and D60 — with the USCS well-graded / poorly-graded verdict.
Well-graded soils pack tight (every void has a smaller grain to fill it) — better fills, better drainage layers stay where uniformity matters instead. D10 also drives permeability via Hazen's k ≈ C·D10².
Formula
Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.
Uniformity Coefficient (Cu) & Curvature (Cc) Calculator is a free uniformity coefficient 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 Uniformity Coefficient (Cu) & Curvature (Cc) Calculator
Cu and Cc from D10, D30 and D60 — with the USCS well-graded / poorly-graded verdict. The calculation implements Cu = D60 ÷ D10; Cc = D30² ÷ (D10 × D60) (ASTM D2487 (USCS); IS 1498). Well-graded soils pack tight (every void has a smaller grain to fill it) — better fills, better drainage layers stay where uniformity matters instead. D10 also drives permeability via Hazen's k ≈ C·D10².
How to use Uniformity Coefficient (Cu) & Curvature (Cc) Calculator
- 1Enter D10 (effective size) in mm.
- 2Enter D30 in mm.
- 3Enter D60 in mm.
- 4Read Cu = D60/D10, Cc = D30²/(D10·D60) instantly — no submit button needed.
Why use Uniformity Coefficient (Cu) & Curvature (Cc) Calculator?
- ✓Implements the standard formula — Cu = D60 ÷ D10; Cc = D30² ÷ (D10 × D60)
- ✓Reference cited on-page: ASTM D2487 (USCS); IS 1498
- ✓Live worked example: the substitution recomputes from your numbers
- ✓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 Uniformity Coefficient (Cu) & Curvature (Cc) Calculator use?+
It computes Cu = D60 ÷ D10; Cc = D30² ÷ (D10 × D60), per ASTM D2487 (USCS); IS 1498. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
Well-graded soils pack tight (every void has a smaller grain to fill it) — better fills, better drainage layers stay where uniformity matters instead. D10 also drives permeability via Hazen's k ≈ C·D10².
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 Uniformity Coefficient (Cu) & Curvature (Cc) Calculator 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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