Pick Method Comparator
Compare discrete and batch picking on total daily labor hours once per-item sort overhead is priced into batch picking, not just travel time.
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Based on your results, these related decisions are available.
How this works
Batch picking, one walk through the floor collecting items for several orders at once, looks like it should always beat discrete picking, one order per walk, since it cuts the number of route walks. But batch picking is not free: items still have to be sorted back into the right order once collected, and that per-item sort overhead can erode or even reverse the travel savings, especially with high items-per-order or a small batch size. This engine prices both the travel savings and the sort overhead, not just the travel side.
Key terms
- Discrete picking: one order per route walk, no sort step needed since each walk only ever touches one order.
- Batch picking: several orders collected in one walk, then sorted back into their original orders, cutting route walks to roughly orders divided by batch size.
- Sort overhead: the extra per-item time batch picking spends dividing a collected batch back into individual orders, the cost discrete picking never pays.
Assumptions
- One route travel-time figure regardless of method
- Sort overhead applies per item, not per batch
Limitations
- Two methods only, not zone picking or wave picking
- One batch size evaluated per run, not a search across batch sizes
Sources
Frazelle, World-Class Warehousing and Material Handling, and de Koster, Le-Duc, and Roodbergen's order-picking literature survey (European Journal of Operational Research).
Worked example
At 40 orders/day, 30 items/order, a 12-minute route, 8 seconds per pick, and a batch size of 5, batch picking cuts route walks from 40 to 8, travel time from 480 to 96 minutes. But a 25-second-per-item sort overhead across 1,200 total items adds 500 minutes back, more than eating the travel savings. Discrete picking wins at 10.7 labor hours/day versus batch's 12.6, the opposite of what a travel-only comparison would suggest.
Common use cases
- Deciding whether batch picking is actually worth the sortation overhead for a given order profile
- Checking whether a small batch size is even earning its travel-amortization benefit
- Continuing from Slotting ABC Velocity Planner's layout decision into a picking-method decision
- Feeding the chosen method's labor hours into Warehouse Throughput Bottleneck's flow check