What does the productivity calculator work out?
Excavator productivity is the volume a machine moves in an hour: the volume in one bucket or blade times the number of cycles in an hour, reduced by the minutes the machine does not work. The calculator applies the same rule to a hydraulic excavator, a wheel loader and a crawler dozer, converts loose volume to bank volume with the swell of the material, and gives the cost per cubic meter.
The Plan tab turns that output into the machine-hours, working days and number of machines needed for a quantity from your bill of quantities, so you can check a schedule before you mobilize.
Why measure output per machine?
- Quantities are priced per cubic meter: the earthworks rate you tender or pay is per m³, while the machine is paid per hour. Output per hour links the two.
- Schedules depend on it: the number of excavators and loaders in the plan comes from the quantity divided by output per machine.
- Loose and bank volumes differ: one bank cubic meter of soil becomes more than one cubic meter in the bucket. Mixing the two overstates progress.
- Lost minutes add up: a machine that works 40 minutes an hour instead of 50 moves a fifth less for the same hire cost.
What inputs do you need?
| Input | Where to find it | Tip |
|---|---|---|
| Bucket capacity, blade load | Machine specification | Use the heaped capacity of the bucket fitted on the machine. |
| Fill factor | Caterpillar fill factor table, your own weighed loads | Blasted rock and blocky material fill less than loose soil. |
| Cycle time | Stopwatch at the face, video from the site | Time 20 or more cycles in normal work and use the average. |
| Productive minutes per hour | Shift reports, machine activity records | Count waiting for trucks, short stops and refueling as lost minutes. |
| Swell | Soil investigation report, laboratory tests | Bank and loose unit weights give swell directly. |
| Cost per hour | Hire contract, owning and operating cost | Include the operator and fuel when the hire rate does not. |
How is productivity calculated?
Excavator
This is Equation 3-1 of the King Saud University course for a hydraulic excavator. When the cycle is timed on site it already holds the real swing and depth, so the swing-depth factor stays at 1.
Wheel loader and dozer
The course converts speed with 1 km/h = 16.7 m/min; the calculator uses the exact 16.67 m/min.
Bank volume and cost
Load factor is Equation 2-7 and cost per unit of production is Equation 2-2 of the same course.
Sources
- King Saud University, CE 419, Chapter 2: Earthmoving Materials and Operations (bank, loose and compacted measure, swell, load factor, Equations 2-1, 2-2, 2-7). Source: KSU.
- King Saud University, CE 419, Chapter 3: Excavating and Lifting, part 1 (Equation 3-1, Example 3-2). Source: KSU.
- King Saud University, CE 419, Chapter 4: Loading and Hauling, part 2 (dozer and wheel loader production, Examples 4-6 and 4-7). Source: KSU.
- Caterpillar, Bucket Fill Factors, cat.com, 30 September 2021. Source: Caterpillar. Last reviewed 21 October 2026.
Worked example: the course machines and a 20,000 m³ cut
The defaults are the course examples, with a swell of 25% and USD 100 an hour as example costs; replace them with your site's figures.
- Excavator: 250 cycles × 0.57 m³ × 95% × 50/60 = 112.8 LCM/h, the 113 LCM/h of Example 3-2. At 25% swell that is 90.3 BCM/h, or USD 1.11 per bank m³.
- Wheel loader: a 0.80-minute cycle gives 2.68 m³ × 75 cycles × 50/60 = 167.5 LCM/h (Example 4-7: 168), or 134 BCM/h.
- Dozer: 0.05 + 0.91 + 0.46 = 1.42 min a cycle, so 7.65 × 60 ÷ 1.42 × 50/60 = about 269 LCM/h. The course gets 271 because it rounds each time to two decimals.
- Plan: 20,000 BCM with the excavator takes 20,000 ÷ 90.25 = 222 machine-hours. Two excavators working 10 hours a day need 12 days; to finish in 10 days you need 3 excavators. The cost is about USD 22,160.
How to read your results
- Loose against bank: report progress in bank m³ when quantities and payment are in bank measure.
- Theoretical against productive output: the gap is the minutes lost each hour. It is usually the cheapest output to win back.
- Cost per m³: compare machines on the same quantity. A bigger machine with a higher hourly rate can still cost less per m³.
- Machines needed: if the plan needs more machines than you have, check the schedule, the working hours or the trucks before hiring more.
How to raise output per machine
- Keep trucks at the excavator: an excavator that waits for trucks loses its productive minutes. Match them with the Haul Truck Cycle & Match Calculator.
- Fit the bucket to the material: the fill factor falls in rock and cemented material.
- Shorten travel and pushes: on loaders and dozers travel time grows with distance while the load stays the same.
- Record hours by machine: compare working, idle, standby and breakdown hours each day in the Equipment Timesheet.
Assumptions and limits
The calculator uses averages from one cycle time, one fill factor and one swell, so it estimates output in steady work. It does not adjust for grade, altitude, operator skill or material changes beyond the inputs you enter; the course gives correction tables for those. Swell varies with moisture and soil type, so take it from your soil report. All defaults are examples, not equipment data. Use the results to plan and compare, then check them against measured cycles and surveyed quantities.