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 five digging choices follow the CAT A–E material descriptions. The calculator uses approximate readings of the CAT A–E graphical ranges. Choosing the more demanding digging or swing case, taking its midpoint, and interpolating 40T/45T size groups are calculator assumptions, not CAT-published formulas. Both the loading estimate and Analysis use the estimated cycle for the selected difficulty and swing angle. Enter a complete cycle to use field measurements instead.
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. Truck loads use heaped body volume in m³; no material-density input is applied.
Bucket loading = whole bucket passes × the condition-based estimated cycle shown in the loading estimate. An entered complete bucket cycle overrides that estimate. Effective loose truck load is the heaped body volume. In-ground equivalent (swell factor included) = effective loose load ÷ (1 + swell/100); swell does not increase truck body capacity.
The four stages are Loading, Loaded haulage, Tipping and Empty haulage. The per-truck stage cards show loading-zone work, loaded travel, tipping-zone work and empty travel. Loading and tipping queue waits are shown separately; the complete per-truck round trip includes them once. Loading work includes manoeuvring, bucket loading and clearance; tipping work includes manoeuvring, tipping/lowering and clearance. Additional time after a stop at queue applies only in the predicted queued zone. Each zone admits one truck until it has completely cleared.
Whole-leg haulage times include acceleration, full-speed travel and slowdown. Average haulage speed = one-way distance ÷ total leg time. Effective maximum speed = absolute speed cap × road factor × haulage route efficiency. Loaded and empty travel have the same cap and different acceleration/slowdown times. Route presets are 90%, Average 80% (default), 70%, or Custom. Estimated ramp times use CAT empty/full-load masses and clearly labelled site acceleration assumptions. Entered ramp times describe 0 to the current effective maximum and back to 0; short routes scale the ramps to the attainable peak. Entered whole-leg times bypass speed estimation and route allowances. Zone manoeuvres, clearance and queue waiting are separate from travel.
Production is limited by available trucks and the capacities of both zones. Mixed fleets use a common estimated queue delay to keep both zone utilizations at or below 100%. Delay belongs to the limiting zone, or is divided equally if both tie. Four-stage trip times use completed-load-weighted averages and add to the average round trip. Loads per day include the work-efficiency allowances. This is a steady-state estimate; individual dispatch interactions and short-lived queues at the other zone are not 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 range: Easy maps to A, Medium to B, Medium to hard to C, Hard to D, and Very hard to E. Swing maps to A below 30°, B from 30–60°, C above 60–90°, D above 90–120°, and E above 120°. The more demanding input chooses the overall case. Shorter/longer are approximate chart readings for that case; Analysis uses their midpoint. These mapping and midpoint rules are calculator assumptions, not an exact CAT formula. The 25T/35T/50T classes map to CAT 23–24T/36T/49T; 40T/45T use interpolation between 36T and 49T. Entered complete cycles bypass this estimate.
Part 1 total trip time uses the selected loading-estimate excavator and haulage-estimate truck: loading zone + loaded travel + tipping zone + empty travel. It includes manoeuvring and clearance but excludes queue waiting and restart after a queue stop. Analysis adds the predicted queues for the selected fleet. Entered whole-leg travel times have no invented acceleration/cruise/slowdown breakdown.
