Grain Size Distribution Calculator
Professional sieve analysis tool for geotechnical engineers, geologists, and construction professionals. Calculate D-values, uniformity coefficient, and soil classification instantly.
Input Method
Sieve Analysis Data
Enter sieve sizes (mm) and the corresponding mass retained (g) for each sieve.
| Sieve Size (mm) | Mass Retained (g) | Action |
|---|---|---|
Analysis Results
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D10 (Effective Size)
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D30
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D50 (Median)
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D60
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Uniformity Coefficient (Cu)
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Coefficient of Curvature (Cc)
Grain Size Distribution Calculator: The Ultimate Guide for Engineers and Geologists
Understanding particle size distribution is fundamental to geotechnical engineering, construction, and earth sciences. Whether you’re designing foundations, analyzing soil stability, or ensuring aggregate quality for concrete, the grain size distribution calculator is your essential analytical tool. This comprehensive guide explains everything you need to know about sieve analysis, D-values, and soil classification.
What is Grain Size Distribution?
Grain size distribution (also called particle size distribution) represents the relative proportions of different-sized particles within a soil or aggregate sample. This analysis reveals critical information about soil behavior, permeability, strength, and suitability for various engineering applications.
When you run a sieve analysis, you separate particles by size using a series of mesh screens with progressively smaller openings. By weighing the material retained on each sieve, you create a distribution curve that becomes the foundation for geotechnical decision-making.
Our advanced grain size distribution calculator transforms your raw sieve data into actionable insights instantly. Instead of spending hours plotting curves manually or wrestling with spreadsheet formulas, you get professional results in seconds.
Key Parameters Explained
D10 (Effective Size): This represents the sieve size where 10% of the material passes through. It’s called the “effective size” because it controls water movement through coarse-grained soils. A smaller D10 indicates finer material with lower permeability.
D30: The particle size where 30% of the material is finer. This value works together with D60 and D10 to evaluate soil gradation quality.
D50 (Median Particle Size): Perhaps the most referenced value, D50 represents the median particle size where exactly half the material is finer and half is coarser. This single number gives you an immediate sense of the overall particle size.
D60: The size where 60% of particles are finer. This critical value combines with D10 to determine the Uniformity Coefficient.
Uniformity Coefficient (Cu): Calculated as Cu = D60 / D10, this parameter tells you how uniform or well-graded your soil is. Cu < 4 indicates uniform soil (poorly graded), while Cu > 4 suggests well-graded material with a good distribution of particle sizes.
Coefficient of Curvature (Cc): Computed as Cc = (D30²) / (D60 × D10), this reveals whether your soil curve is smooth and continuous. For well-graded gravels, Cc should be between 1-3.
How to Use the Grain Size Distribution Calculator
Step 1: Prepare Your Sieve Analysis Data Begin with your sieve analysis results. You’ll need the sieve opening sizes (in millimeters) and the mass retained on each sieve (in grams). Always include the pan (size = 0) to account for the finest particles.
Step 2: Enter Your Data Our calculator offers four flexible input methods:
- Manual Entry: Type directly into the dynamic table. Add or remove rows as needed for your sieve stack.
- CSV Upload: Have existing data? Upload a CSV file with two columns: Sieve Size (mm) and Mass Retained (g).
- Preset Materials: Analyze common materials like well-graded sand, uniform beach sand, or gravel instantly.
- Sample Data: New to sieve analysis? Load sample data to see how the calculator works.
Step 3: Review Your Input Double-check that your sieve sizes increase from bottom (pan) to top (largest sieve). The calculator automatically sorts data, but confirming input prevents errors.
Step 4: Calculate Click the “Calculate Grain Size Distribution” button. The calculator processes your data using advanced interpolation algorithms to find precise D-values.
Step 5: Interpret Results Review the automatically generated statistics, classification, and distribution curve. The interactive chart allows you to hover for detailed information at each sieve size.
Step 6: Export and Share Download your results as a CSV file, save the chart as an image, print a professional report, or share directly to social media platforms.
Understanding Your Results
Reading the Distribution Curve The grain size distribution curve plots particle size (logarithmic x-axis) against percent finer (y-axis). A steep curve indicates uniform particles, while a gentle slope suggests well-graded material spanning many sizes.
Soil Classification Interpretation The calculator provides Unified Soil Classification System (USCS) designation:
- GW: Well-graded gravel – Excellent for drainage and foundations
- GP: Poorly-graded gravel – May need compaction effort
- SW: Well-graded sand – Ideal for concrete and drainage layers
- SP: Poorly-graded sand – Uniform sand that may liquefy
- GM/GC: Gravel with silt/clay fines – Reduced drainage, increased cohesion
- SM/SC: Sand with silt/clay fines – Variable engineering properties
Practical Implications
- High Cu (>6 for sands, >4 for gravels): Well-graded, dense packing, good stability
- Low Cu: Uniform size, potential for liquefaction, easy to compact
- Cc outside 1-3: Gap-graded or missing particle sizes, may be unstable
- High fines content (>50%): Fine-grained soil behavior dominates
Applications Across Industries
Construction & Civil Engineering
- Foundation design and bearing capacity assessment
- Drainage layer specification for roadways
- Concrete aggregate optimization
- Earthwork compaction control
Geotechnical Engineering
- Slope stability analysis
- Seismic liquefaction potential evaluation
- Ground improvement design
- Dam and embankment material selection
Environmental Science
- Contaminant transport modeling
- Aquifer characterization
- Soil remediation planning
Agriculture
- Soil texture classification for crop suitability
- Irrigation design
- Erosion control measures
Mining & Materials
- Aggregate quality control
- Ore size reduction evaluation
- Tailings characterization
Best Practices for Accurate Results
Sieve Analysis Quality Control
- Always oven-dry samples before testing
- Use proper sieving time (typically 10-15 minutes mechanical shaking)
- Ensure sieves are clean and undamaged
- Weigh to consistent precision (0.1g minimum)
- Include fines from sieve cleaning in final pan weight
Data Entry Tips
- Enter sieve sizes in descending order from largest to smallest
- Don’t skip intermediate sieves in the standard series
- Record zero masses explicitly rather than leaving blank
- Use standard sieve sizes (75, 37.5, 19, 9.5, 4.75, 2.36, 1.18, 0.6, 0.3, 0.15, 0.075 mm)
Result Validation
- Total mass should equal original sample weight (within 0.1%)
- Percent finer should decrease smoothly
- D-values should fall within your sieve range
- Cu and Cc should align with your visual curve assessment
Frequently Asked Questions
Q: How many sieves do I need for accurate analysis? A: Use at least 6-8 sieves spanning your expected particle range. More sieves provide better curve definition, especially if you’re trying to identify gap-grading.
Q: Can I use this calculator for materials other than soil? A: Absolutely! It works for any granular material: aggregates, powders, minerals, coffee grounds, or pharmaceutical particles. Just ensure your sieve sizes and units are consistent.
Q: Why is my Cu value showing as “Infinity” or extremely high? A: This occurs when D10 approaches zero (very uniform fine material). Check your data entry, especially for the pan size which should be 0 mm.
Q: What’s the minimum sample size for reliable results? A: For coarse materials, use at least 500g. For sands, 200-300g is typical. For fine-grained soils, 100g may suffice. Always follow ASTM or AASHTO standards for your material type.
Q: How do I handle particles larger than your largest sieve? A: Include them as the top sieve with 100% retained. For boulder-sized particles, note them qualitatively as they affect mass but can’t be accurately sieved.
Q: Can this calculator replace professional laboratory software? A: While our calculator provides accurate calculations and classification, formal projects requiring certification should use validated laboratory software with full traceability.
Q: Why does the curve use a logarithmic scale for particle size? A: Particle sizes in nature span orders of magnitude. Logarithmic scales compress this range for clear visualization and align with standard geotechnical practice.
Q: My soil classification shows “Fine-grained Soil” but I have mostly sand. Why? A: USCS classification gives priority to fines content. If >50% passes the 0.075 mm sieve, it’s fine-grained regardless of sand content above that size.
Q: How accurate are the D-value calculations? A: Our calculator uses linear interpolation on a log scale, matching ASTM D2487 standards. Accuracy depends on your sieve spacing – closer sieves near target percentages yield better precision.
Q: Can I save my analysis for future reference? A: Yes! Use the CSV export to save raw data. For full reports, use the print function which includes all parameters and the chart. Your browser also auto-saves input data for 30 days.
Q: What if I don’t have data for the pan (size = 0)? A: Always include the pan! The finest fraction significantly affects classification and D-values, especially D10. Omitting it leads to incorrect results.
Q: How do I interpret gap-graded soils? A: Gap-graded soils show a flat section on the curve. The calculator’s Cc value will fall outside the 1-3 range. These soils may be prone to segregation and require special handling in construction.
Ready to Transform Your Sieve Analysis Workflow?
Stop wrestling with spreadsheets and manual curve plotting. Our grain size distribution calculator delivers professional, accurate results in seconds, letting you focus on engineering decisions rather than calculations.
Bookmark this tool for immediate access during fieldwork, laboratory analysis, or design reviews. With sample data, preset materials, and multiple export options, it’s the only sieve analysis tool you’ll ever need.
Empower your geotechnical investigations with instant, accurate grain size distribution analysis.