Excavation Fleet Planner

Goal: Move X m³ of dirt over Y meters distance.

Question: What size excavator, and how many dump trucks of which sizes, will give you the highest daily productivity and the lowest cost per m³?

My job

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Task quantity

Volume to haul

Working hours

Loading conditions

One bucket: dig and fill → swing loaded → unload → return empty.

Cycle results by excavator size

CAT’s typical bands are approximate chart readings for favourable conditions and 60–90° swing, not ranges for your selected difficulty and angle. Size groups are matched approximately; 40T and 45T sit between CAT’s 36T and 49T groups. The calculated cycle used is a planning estimate.

Haulage conditions

Loading zone · one truck at a time

Truck B waits outside until Truck A finishes loading and completely clears the loading zone. This applies to both reversing and drive-in layouts.

Tipping zone · one truck at a time

Truck B waits outside until Truck A has tipped, lowered its body and completely cleared this zone.

Loaded haul and empty return include accelerate, full road speed and slow down. Zone manoeuvres, loading, tipping, zone clearance and queue waiting are separate. Travel starts after clearing a zone and ends at the next zone’s queue.

Loaded travel speed
Empty return speed

Work efficiency

Separate allowances for job downtime, operator output and mechanical downtime. Exclude rest and fleet waiting already calculated.

Job efficiency

Allowance for work interruptions from planning, permits, design, communication and audits.

Operator efficiency

Productive minutes in each working hour.

Mechanical efficiency

Production time available after servicing and breakdowns.

Assumed mechanical availability · low downtime

Downtime assumptions

Assumes these interruptions stop fleet production. Service outside working hours does not reduce availability.

Machine availability & rates

Tick the machines available for your job. Only these machines are compared. Rates are optional; enter your wet hire quotes in AUD/hour, including operator and fuel.

Excavators (wet hire)

Dump trucks (wet hire)

Bucket & cycle settings

Editable planning defaults. Baseline cycle = medium digging at 90° swing.

Truck waiting & downtime

Truck waiting is time spent queuing outside the loading or tipping zone. Only one truck occupies each zone. The next truck enters after the first has completed its work and cleared the zone. The percentage is the average share of each complete truck cycle spent in these queues.

Example: 30% waiting means an average of 3 minutes queuing in a 10-minute total cycle. The remaining 7 minutes cover manoeuvres, loading, travel, tipping and clearing the zones.

The figure is averaged across the fleet; individual trucks may differ. It does not automatically tell you how many trucks to remove. Compare a smaller fleet on the graph to see how productivity and cost change.

Waiting is already included in daily output. Hire cost still includes the full paid shift. Do not deduct this waiting percentage again in Work efficiency.

Servicing and breakdowns are separate mechanical downtime, accounted for under Mechanical efficiency. Rest breaks and other job interruptions have their own allowances.

Digging & swing guidance

A bucket cycle includes dig and fill, swing loaded, unload and return empty. More difficult digging or a larger swing usually means a longer cycle.

CAT’s Performance Handbook, Edition 50, section 5, pages 5-24–5-25 (PDF pages 67–68), describes harder digging, greater swing angles, digging depth, truck position and obstructions as factors that increase cycle time. Its condition categories combine these effects; the handbook does not give independent multipliers for these dropdowns.

The calculator’s Easy / Medium / Hard / Very hard choices simplify that guidance. The 60% digging / 40% swing split and numerical adjustment factors are our planning assumptions, not CAT-published factors. Open Bucket & cycle settings to change the baseline cycles, or enter a complete cycle directly.

Read CAT cycle-time guidance ↗

How the calculations work

Size labels are rounded classes. Production uses loose body volume and bucket capacity, converted to the selected volume basis using swell. No density or payload limiting is applied. Check rated loads before operating.

Bucket loading = whole bucket passes × complete bucket cycle. Loading-zone occupancy = start from stopped queue + manoeuvre to loading + bucket loading + clear loading zone. The loading slot remains occupied until the loaded truck has completely left; only then can the next truck start entry. Loading clearance applies to reversing and drive-in layouts. The entered clearance is a separate zone movement: estimated and entered haul travel must exclude this same movement so it is counted once. Tipping-zone occupancy = start from stopped queue + manoeuvre to tipping + tipping + clear tipping zone. Setting off starts at 0 m/s; each zone has an editable 5-second startup allowance before positioning. Use 0 if a measured manoeuvre already includes startup. These startup allowances apply to every zone entry because estimated travel ends at a stop before the zone. They are separate from acceleration on the haul road. Each zone holds one truck; the next truck waits outside until the previous truck clears it. Manoeuvre defaults are 20 seconds for reversing and 0 for drive-in/through. Both remain editable, and switching approach remembers each entered allowance. Truck round trip before queues = loading-zone occupancy + loaded travel + tipping-zone occupancy + empty travel. Estimated travel includes acceleration, cruising and slowdown, adjusted for route efficiency (base travel time ÷ efficiency fraction). Presets are Good 95%, Average 85%, Below average 75%, or Custom. Entered travel times already include route interactions and bypass that allowance. Travel distance and times exclude zone manoeuvres and clearance, avoiding double counting. Production is limited by available trucks and the capacity of both zones. A long tipping-zone occupancy can create a tipping bottleneck. Mixed fleets use each truck’s body volume and loading time, with a common estimated total queue delay that keeps both zone utilizations at or below 100%. Queue delay is attributed to the limiting zone, or divided equally if both tie. This is a steady-state planning estimate, not an individual dispatch simulation. Short-lived queues at the other zone and interactions between the zones are not separately simulated.

Daily output = hourly production × (shift − rest) × job efficiency × operator efficiency × mechanical availability. These are separate, non-overlapping allowances: job efficiency covers work interruptions from planning, permits, design, communication and audits; operator efficiency covers productive minutes during otherwise available work; mechanical availability covers production-interrupting service and breakdowns. Rest and calculated fleet waiting must not be deducted again. Mechanical availability = operating interval ÷ (operating interval + included service downtime + breakdown downtime). One common mechanical allowance is applied to the fleet; it does not model each machine failing independently. Cost = fleet hourly rate × full shift ÷ daily output. Total job cost = unit cost × input volume; this does not round billing to whole shifts.

Completion days are equivalent working days from steady-state output; initial dispatch, final delivery, last partial loads and compaction constraints are excluded. Very small jobs need a detailed schedule.

Cycle adjustment uses a provisional 60% digging / 40% swing split. Digging factors: 0.80, 1.00, 1.35, 1.70. Swing factors at 30°, 60°, 90°, 120°, 180°: 0.60, 0.80, 1.00, 1.20, 1.60. These are planning assumptions, not CAT-published factors. Entered complete cycles bypass them.