Equipment Productivity Calculator

Equipment productivity is the volume or weight of material a machine moves per hour. Planners use it to size fleets, estimate durations for earthworks and compare the cost per cubic metre of different machines. An excavator that looks cheap per hour can be expensive per m³ if it is badly matched to the trucks it loads.

How to use the calculator

1. Enter the bucket or body capacity of the machine.
2. Enter the cycle time: load, swing, dump and return.
3. Set the bucket fill factor for the soil type and the job efficiency (working minutes per hour).
4. Read the hourly output and the time needed for your total quantity.

The formula

Output (m³/hr) = Bucket capacity × Fill factor × (3600 / Cycle time in seconds) × Efficiency. Divide by the soil swell factor if you need bank (in-situ) volume rather than loose volume.

Worked example

An excavator with a 1.2 m³ bucket, a 20-second cycle, a fill factor of 0.9 for common earth and 50 working minutes per hour (efficiency 0.83): 1.2 × 0.9 × 180 × 0.83 = 161 m³/hr loose. With a swell factor of 1.25, that is about 129 m³/hr bank volume. Excavating 5,000 m³ in place takes about 39 working hours.

Typical fill factors

• Moist loam or sandy clay: 1.0 to 1.1
• Sand and gravel: 0.95 to 1.0
• Hard, tough clay: 0.8 to 0.9
• Well-blasted rock: 0.6 to 0.75

Matching the fleet

Trucks should be loaded in 3 to 5 passes. Calculate the truck cycle (load, haul, dump, return) and the number of trucks needed so the excavator never waits. Idle loaders and idle trucks both raise the cost per m³.