Grain Size Distribution Calculator
Example Data Table
| Sieve Size (mm) | Retained Mass (g) | Description |
|---|---|---|
| 4.75 | 20 | Very coarse particles retained. |
| 2.36 | 40 | Coarse particles retained. |
| 1.18 | 65 | Medium particles retained. |
| 0.60 | 80 | Fine coarse fraction retained. |
| 0.30 | 55 | Medium fine fraction retained. |
| 0.15 | 28 | Fine fraction retained. |
| 0.075 | 8 | Very fine fraction retained. |
| 0.01 | 4 | Pan or ultra-fine fraction. |
Formula Used
Percent retained = (retained mass ÷ total sample mass) × 100.
Cumulative percent retained = running sum of retained percentages.
Percent passing = 100 − cumulative percent retained.
D10, D30, D50, and D60 are particle sizes at 10%, 30%, 50%, and 60% passing.
The calculator estimates these values using logarithmic interpolation between surrounding sieve points on the grading curve.
Uniformity coefficient = D60 ÷ D10.
Curvature coefficient = (D30²) ÷ (D10 × D60).
Weighted mean size uses retained mass and representative sieve interval size.
How to Use This Calculator
- Enter sieve opening sizes in millimeters.
- Enter retained mass for each sieve row.
- Add more rows for extra sieve intervals.
- Press Calculate Distribution.
- Review percent retained, passing, and coefficients.
- Inspect the Plotly grading curve.
- Download CSV for spreadsheet analysis.
- Download PDF for reporting and archiving.
FAQs
1. What does this calculator measure?
It converts sieve retention data into a full grain size distribution. You get percent retained, cumulative retained, percent passing, grading coefficients, interpolated Dx values, and a chart.
2. Why is percent passing important?
Percent passing shows how much material is finer than each sieve size. It helps compare distributions, classify materials, and evaluate grading behavior for engineering, data analysis, and quality control.
3. What are D10, D30, D50, and D60?
These are characteristic particle sizes taken from the distribution curve. For example, D50 is the median size, while D10 and D60 support coefficient calculations.
4. What does the uniformity coefficient mean?
Uniformity coefficient compares D60 with D10. Larger values usually indicate a wider spread of particle sizes, while smaller values suggest a more uniform sample.
5. Why does the calculator use logarithmic interpolation?
Grain size curves are commonly interpreted on semi-log plots. Log interpolation gives more realistic Dx estimates between adjacent sieve points than simple linear size interpolation.
6. Can I use any units for sieve size?
Use one consistent size unit throughout the table. This version is labeled in millimeters, and all derived sizes and chart values follow the same unit.
7. What happens if my sieve rows are unordered?
The calculator sorts entered sieve sizes from largest to smallest automatically. That keeps cumulative calculations and the grading curve consistent.
8. What should I do with the exported files?
Use CSV for deeper numerical work in spreadsheets or scripts. Use PDF for project reports, lab documentation, approvals, and presentation-ready summaries.