About this tool Calculate the estimated payload per bucket load from the rated (struck) bucket volume, loose material density, and bucket fill factor. Useful for production planning, truck matching, and haulage cycle calculations.
Includes presets for common materials from topsoil to iron ore with typical loose densities and fill factors. Fill factor accounts for the difference between the struck volume and the actual heaped load — less than 1.0 for blocky rock, greater than 1.0 for light bulky material.
Always check that the calculated payload does not exceed the machine's rated operating capacity. The bucket may hold the volume but the machine may not safely lift the weight.
How to use this tool 1. Enter the rated bucket volume — from the machine specification (SAE struck capacity).
2. Select a material preset or enter custom values — loose density in kg/m³ and fill factor.
3. Read the heaped volume and payload — in m³, kg, and tonnes.
Technical information Heaped volume = rated volume × fill factor
Payload = heaped volume × loose material density
Fill factors: 0.80–0.85 for blasted rock, 0.95 for gravel, 1.0 for sand/clay, 1.05–1.10 for loose topsoil. Per Caterpillar Performance Handbook.
Limitations Fill factors are approximate and depend on material fragmentation, moisture, operator skill, and bucket design. Site-specific measurement is recommended for production estimates.
Loose density varies significantly with moisture content and fragmentation. The presets are typical mid-range values — measure on site for accuracy.
Revision history 4 August 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.
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