Truck capacity mode
Payload weight (t)
Loose volume (m³)
Choose how you know the truck capacity.
Density mode
Loose density (t/m³)
Bank density + swell
Use bank density when you know in-situ density.
Target mode (optional)
No target
Loose volume target (m³)
Weight target (t)
Add a target to estimate total loads and hours.
Calculate Passes
Key Inputs That Control Pass Count
Bucket rating alone is not enough for reliable planning. The effective volume per pass is bucket capacity multiplied by fill factor. A 3.0 m³ bucket at 90% fill delivers 2.70 m³/pass. Small changes in fill have large impacts because the pass count is a ceiling calculation, so your last pass often sets the overall loading time. Measure.
Density and Swell Conversions for Earthworks
Haul planning usually mixes in‑situ and loose quantities. When you enter bank density with swell, the calculator converts to loose density using ρL = ρB ÷ (1 + swell). For example, 1.80 t/m³ bank with 20% swell becomes 1.50 t/m³ loose. That conversion drives both the computed truck loose volume and the resulting passes. Typical swell: sand 5–12%, clay 10–25%, blasted rock 25–65%.
Cycle Time, Efficiency, and Hourly Output
Passes per hour are based on cycle time and job efficiency. If one pass takes 28 seconds and efficiency is 85%, productive passes are (3600/28)×0.85 ≈ 109 passes/hr. Multiply by effective bucket volume to estimate loose production. This helps compare loaders, check whether trucking can be kept busy, and size shift targets. Record cycle time as an average over at least 10 passes.
Example data (typical soil load):
Bucket (m³)
Fill (%)
Truck Payload (t)
Bank Density (t/m³)
Swell (%)
Cycle (s)
Efficiency (%)
3.000
90
18.0
1.80
20
28
85
Managing Overfill, Spillage, and Safety Margins
The calculator rounds up passes to avoid short loads and reports estimated overfill. Overfill can increase spillage, cleanup, and tire damage, and may exceed legal payload. Use the overfill indicator to tune fill factor, adjust truck capacity assumptions, or switch to volume mode when body heaping limits govern instead of weight. If overfill exceeds 5–8%, review safety and site rules.
Planning Daily Targets and Truck–Loader Balance
For targets, the tool converts your goal into loose volume and computes total loads, total passes, and estimated hours. Use this to balance fleet ratios: if loads/hr is low, add trucks or reduce spotting delays; if loads/hr is high, the loader may be underutilized. Pair these outputs with haul distance and travel times for full cycle planning.
FAQs
1) What is a “bucket pass” in this context?
A single load–swing–dump cycle that places one bucketful into the truck body. Passes are counted using the effective bucket volume after the fill factor is applied.
2) Should I use bank or loose density?
Use loose density when your densities come from stockpile or truck measurements. Use bank density with swell when densities are in-situ from geotech reports or cut/fill quantities.
3) Why does the calculator round up passes?
Truck loads must meet the required volume, so the last partial pass still takes a full cycle. Rounding up prevents short loads and reflects field loading practice.
4) How do I estimate cycle time accurately?
Time at least 10 consecutive passes, include bucket fill, swing, dump, and return, then average. Recheck when haul road layout, pile height, or truck positioning changes.
5) What efficiency value should I enter?
Use 70–90% for most jobs. Higher values fit controlled sites with minimal delays; lower values reflect congestion, frequent spotting, or poor visibility and rework.
6) Why can overfill be high even with correct passes?
Because passes are integers. If the exact pass count is 4.2, the tool uses 5 passes, which can overfill. Adjust fill factor or use a smaller bucket for the topping pass.
7) Can this replace a full production study?
It provides a fast, defensible estimate for planning and bids. For final scheduling, add haul distance, travel speed, dumping time, and queueing to complete the truck cycle model.