31 Oct

Pick-to-Light vs Put-to-Light vs Put Wall: real differences and when to use each one

In operations with many order lines, performance hinges on three fronts: walking less, deciding less, and confirming better. Light-guided systems target exactly that: they show where to act, how many units, and request a simple confirmation. Not all of them serve the same purpose, though. Below we compare Pick-to-Light (PTL), Put-to-Light, and Put Wall with a practical lens: what problem they solve, when they make sense, and how they fit with multi-order carts and your WMS.

What each system solves

• Pick-to-Light (PTL)

Designed for shelf picking. If your pain points are errors with look-alike items, hesitation in aisles, or slow training, PTL reduces the decision to a single action: the module lights up at the correct location, shows the quantity, and the operator confirms.
Result: fewer mix-ups, steadier pace, and less end-of-line rechecking.

• Put-to-Light

Built for consolidation. After collecting items—ideally in batches—you scan the product and the light tells you which order it belongs to.
Result: fast sorting with no cross-assignments or misroutes.

• Put Wall

The “structured” version of put: a wall/shelving with one cubby per order, all with lights and confirmation. It’s made for waves of many small orders and tight cut-off times.
Result: clean closes within the shipping window and full visibility of progress.

How they work

• PTL guides where you pick: it takes you to the exact location, shows the quantity, and asks you to confirm right there. Decision-making becomes automatic and the operator barely looks away from the product.
• Put-to-Light guides where you distribute: after the route, each scan lights up the correct order compartment; you confirm and the system moves on. The flow is natural and keeps order even with dozens of open orders.
• Put Wall organizes consolidation: each order has its cubby. Lights indicate where to place, when to review, and when to close. At the end, the order goes straight from the wall to packing, already validated.

When each one makes sense

• Errors due to very similar SKUs, heavy rotation in the same aisle, or work in cold/frozen areas → PTL. The harder it is to distinguish at a glance, the more location-based guidance shines.
• You pick in batches and need to distribute quickly to many orders → Put-to-Light. Sorting stops being a bottleneck; each scan lights its destination and the pace holds.
• Campaigns with strong peaks (Black Friday) and strict dispatch windows → Put Wall. The wall absorbs volume, gives visibility, and lets you close waves without improvisation.
• Aisles are congested but consolidation space is ample → Put Wall or Put-to-Light. Moving complexity to a controlled area organizes the day.

In practice, multi-order carts + guided put is highly effective: you do one route to feed many orders and close error-free in the consolidation zone.

Which KPIs improve (and why)

• Picking accuracy
  PTL eliminates the “I grabbed the SKU next to it” error: confirmation happens at the correct location. Put-to-Light and Put Wall reduce assignment errors during consolidation.
• Lines/hour and orders/hour
  By removing searches and doubts, cadence increases. With Put Wall, simultaneous consolidation multiplies close-out speed when there are many small orders.
• Order-to-Ship and OTIF
  Less rework and more predictable closes. In peaks, the wall lets you finish complete waves within the shipping window.
• Returns due to warehouse error
  They drop because you confirm at the point of action and each order remains physically separated in the wall or its compartment.

Integration and rollout

These systems work as a layer: they exchange orders, lines, and confirmations with your WMS/ERP (API or CSV) and start in a pilot zone. If you already use multi-order carts, the fit is natural: one route, guided consolidation, and you measure the change with the same KPIs as always. No need to switch anything off or redesign the entire warehouse.

Common mistakes and how to avoid them

• Guiding without structuring consolidation
  When picks arrive unstructured, put becomes slow. Define waves and batch sizes before turning on lights: the system then knows how many orders are “live” and at what pace they should close.
• Sizing the wall “by eye”
  A small Put Wall saturates; an oversized one occupies critical space. Calculate cubbies per wave based on cut-offs, average order size, and packing capacity; leave comfortable working aisles to avoid blockages.
• Forgetting traceability where it matters
  If you need lot, serial, or expiry, capture it at source (scanner or PTL with confirmation). Trying to reconstruct it at the end adds time and errors.
• Neglecting ergonomics
  Module height, reach, and display visibility dictate cadence. Good design enables fast work without awkward postures or micro-stops.

One-line scenarios

• Fashion e-commerce: batch carts → Put Wall in waves; PTL for “look-alike” families.
• Click & Collect retail: PTL in high-rotation aisles + Put-to-Light in consolidation.
• Pharma/parapharma: PTL with lot capture + guided consolidation; FEFO operational.
• Frozen: PTL to minimize time in the freezer; consolidation in a temperate area with Put-to-Light.

Conclusion

PTL is the answer when the problem is at picking: too many decisions and errors from similarity.

Put-to-Light and Put Wall shine when the bottleneck is consolidation: many open orders and urgency to close.

Together—and supported by multi-order carts—they help you walk less, decide less, and confirm better, which is where the real gains are.

Want to review this with your order mix and real cut-offs? Contact us: we’ll prepare a tailored proposal—PTL, Put-to-Light, Put Wall and/or multi-order carts—layered on your system and ready to pilot without stopping operations.