The Excavation Time Calculator is a helpful tool used to estimate how long it will take to complete an excavation project. This calculator is widely used by contractors, engineers, and project planners to assess the time required to dig out soil, sand, or other materials using excavating machinery. It takes into account factors like the total volume of material, the machine’s productivity rate, and real-world efficiency to give an accurate time estimate. This helps in budgeting labor, scheduling resources, and avoiding costly delays.
Whether you’re working on a small residential project or a large construction site, knowing how much time an excavation will take can significantly improve planning accuracy and site logistics.
Formula of Excavation Time Calculator
Excavation Time = Volume / (Productivity × Efficiency)
Where:
- Excavation Time is measured in hours
- Volume is the total amount of material to be excavated (in cubic meters or cubic yards)
- Productivity is the rated output of the equipment (in cubic meters per hour or cubic yards per hour)
- Efficiency is a decimal between 0.6 and 0.9, accounting for real-world losses like repositioning, operator breaks, and idle time
To further break down Productivity, use this optional sub-formula:
Productivity = Bucket Capacity × Cycles per Hour × Fill Factor
Where:
- Bucket Capacity is the size of the excavator’s bucket
- Cycles per Hour is the number of full scoops in an hour
- Fill Factor is how much of the bucket is typically filled (usually 0.8 to 1.0)
This formula gives a clear and practical estimate of how long your excavation project will take under typical conditions.
Quick Reference Table
| Use Case | Input Required | Output |
|---|---|---|
| Standard excavation | Volume, machine productivity, efficiency | Estimated hours |
| High accuracy jobsite planning | Bucket size, cycles/hr, fill factor | Real-world performance |
| Cost estimating | Machine rental hours × rate | Labor + equipment cost |
| Adjusting for slow terrain | Lower efficiency multiplier (e.g., 0.6 instead of 0.9) | Adjusted excavation time |
This table helps you quickly adapt the formula to your specific construction or project management needs.
Example of Excavation Time Calculator
Suppose you’re excavating 1,200 cubic meters of soil. Your excavator has a productivity of 100 m³/hour, and you’re estimating real-world efficiency at 0.75 due to site conditions.
Excavation Time = 1200 / (100 × 0.75) = 16 hours
This means the excavation will take approximately 16 working hours to complete under these conditions.
Now, if you know the excavator’s bucket is 1.5 m³, the operator can complete 300 cycles/hour, and the fill factor is 0.9:
Productivity = 1.5 × 300 × 0.9 = 405 m³/hour
Then, the time becomes:
Excavation Time = 1200 / (405 × 0.75) ≈ 3.95 hours
This shows how much the choice of machine and operation efficiency impacts overall time.
Most Common FAQs
You should reduce the efficiency factor. For soft soil and minimal delays, use 0.9. For tough rock or limited access areas, lower it to 0.6 or even 0.5.
Yes. Once you know the total excavation time, multiply it by your equipment rental and labor rates to estimate your total cost more accurately.
For dry soil, a fill factor of 0.9 to 1.0 is common. For wet or rocky materials, the fill factor may drop to 0.6 to 0.8, depending on how well the bucket fills and retains material.