Inputs
Enter daily volume and operating assumptions. Use the advanced options to include growth, buffers, and bay allocation.
Example Data
These sample values represent a typical site logistics scenario.
| Parameter | Example | Notes |
|---|---|---|
| Inbound volume per day | 120 units | Deliveries of materials and components. |
| Outbound volume per day | 60 units | Waste removal and dispatches. |
| Units per truck | 20 | Average payload converted to units. |
| Operating hours | 10 hours | Receiving window for the shift. |
| Service + maneuver | 45 minutes | Live load/unload plus spotting and paperwork. |
| Peak factor | 1.4 | Captures concentrated arrival periods. |
| Utilization target | 0.75 | Leaves headroom to reduce queues. |
Formula Used
The calculator converts daily volume to daily trucks, estimates peak arrival rate, and sizes bays using a utilization-based throughput model:
- Trucks/day = (Inbound + Outbound) ÷ Units per truck
- Peak trucks/hour = (Trucks/day ÷ Operating hours) × Peak factor
- Service time (hours) = (Service + Maneuver + Buffer) ÷ 60
- Bays = (Peak trucks/hour × Service time) ÷ Target utilization
- Required bays = ceil(Bays × (1 + Contingency%))
If you choose dedicated bays, the total is split by inbound share. For high variability sites, increase contingency and reduce utilization.
How to Use This Calculator
- Pick a consistent unit (pallet, bundle, or delivery unit) for inbound and outbound.
- Enter operating hours for the receiving window of your shift.
- Estimate realistic service and maneuver minutes from site observations.
- Set the peak factor to reflect bursty arrivals or appointment schedules.
- Choose a utilization target; lower values reduce queues during peaks.
- Use growth and contingency to capture near-term changes and variability.
- Click Calculate and download CSV or PDF for reporting.
Demand drivers for loading bays
Loading bays support continuous material flow, waste removal, and scheduled dispatches. Demand rises with trade stacking, prefabrication deliveries, and restricted delivery windows. For planning, treat daily volume as standardized “units” (pallets, bundles, or cages) so different suppliers can be compared consistently, safely.
Converting volume into truck activity
Trucks per day are estimated by dividing total inbound and outbound units by average units per truck. The operating hours define the receiving window, while the peak factor concentrates arrivals into busy periods. Peak-rate sizing prevents underestimating bays when deliveries cluster around crane time, shift changes, or access permits.
Service time components that change capacity
Bay service time includes live load or unload time plus maneuvering, checks, and paperwork. Adding a turnaround buffer captures site-specific delays such as security screening, traffic marshaling, or forklift availability. Reducing service time often saves more bays than adding hours because it improves throughput at every demand level.
Utilization targets and queue control
Utilization is the planned intensity of bay use during peaks. Targets around 0.70–0.80 leave headroom for variability and prevent queues spilling into haul roads. A contingency margin further covers minor downtime, shift breaks, and uneven arrival patterns. If your peak utilization exceeds 85%, consider appointment slots or an extra bay.
Example scenario with practical interpretation
Example inputs: inbound 120 units/day, outbound 60 units/day, 20 units/truck, 10 operating hours, 35 service minutes, 10 maneuver minutes, 5 buffer minutes, peak factor 1.4, utilization 0.75, growth 15%, contingency 10%. This yields about 10.35 trucks/day, a peak rate near 1.45 trucks/hour, and a service time of 50 minutes. The calculated requirement is 2 bays with Low queue risk, supporting site capacity near 1.8 trucks/hour at the target utilization.
FAQs
1) What should I use as a “unit” for volume?
Use a repeatable unit like a pallet, bundle, cage, or delivery package. Convert each supplier’s load into that unit so daily inbound and outbound volumes stay consistent across trades.
2) How do I pick units per truck?
Use historical delivery tickets or observation logs. If loads vary, take a weighted average across common truck types. Conservative values usually prevent under-sizing bays.
3) What does the peak factor represent?
It scales average arrivals into a realistic busy-hour rate. Use higher values when access windows are tight, deliveries cluster in mornings, or appointment compliance is poor.
4) Why does utilization matter so much?
Higher utilization leaves little slack, so small delays become queues. Planning at 0.70–0.80 typically improves reliability and keeps trucks from blocking internal roads.
5) When should I add a turnaround buffer?
Add it when you see repeatable delays outside the core load/unload time, such as security checks, trailer spotting, paperwork, or limited handling equipment during certain hours.
6) Should I choose shared or dedicated bays?
Shared bays maximize flexibility when arrivals fluctuate. Dedicated bays help when inbound and outbound flows conflict, traffic must be separated, or certain materials need controlled access.
7) How can I reduce bay demand without expanding docks?
Shorten service time using better staging, pre-kitting, and faster handling equipment. Extend receiving hours, improve appointment discipline, and separate paperwork from dock time to raise throughput.