Resources / Picking
Pick to Light: How Light-Directed Picking Works and Pays Off
Pick to light uses lit displays at each slot to show pickers where to pick and how many. See how it works, where it pays off, and how put to light differs.
6 min read
· Updated
November 2026
At a glance
How it works
In pick to light, a light and display at each location show the picker which slot to pick from and how many units. The picker takes the units and presses a button to confirm.
Where it fits
Fast-moving SKUs in flow rack or shelving, where a small share of items drives most volume. MHI points to roughly 20% of SKUs making up about 80% of order volume.
The trade-off
Fast, accurate, and easy to learn, but every location needs hardware. Costs grow with location count, and re-slotting means remapping lights in software.
Pick to light is a light-directed order picking system in which lights and small displays mounted at storage locations show pickers which location to pick from and how many units to take, and pickers confirm each pick by pressing a button.
Paper pick lists and handheld scanners make pickers read, search, and confirm at every stop. In a fast-moving area, those seconds of reading and searching add up across a shift, and so do the errors from reaching into the wrong slot. Pick to light removes the reading: the location lights up, shows a quantity, and the picker presses the button when done.
This guide explains how pick to light works, where it pays off, how put to light differs, its benefits and limits, how to measure it, and how it fits with robotics. Pick to light is a guidance technology, not a picking method, so it runs inside a picking method such as zone picking or batch picking, often released in waves. The order picking methods guide covers those choices.
How pick to light works
MHI, the U.S. material handling industry association, describes pick to light, also called pick-by-light or light-directed picking, as light devices mounted at item locations on flow rack, shelving, workstations, or other storage media. A typical cycle runs like this:
Order launch. The operator scans a barcode license plate on a tote or shipping container to start an order in their zone.
Light and quantity. LEDs light up at each location that holds an item for the order, and a small display shows how many units to take.
Pick and confirm. The picker takes the units and confirms, usually by pressing a button on the device, then moves to the next lit location.
Pass or close. When no lights remain in the zone, the tote moves on to the next zone or to packing.
Control software sits between the lights and your WMS or ERP, turning order lines into lit locations and sending confirmations back. Lights can also go on carts: a 2024 study in the journal Logistics describes pick-to-light displays installed at picking locations or mounted on picking carts. On a cart, lights can show which of several order totes gets each unit during a cluster pick.
Where pick to light fits
According to MHI, pick to light works best where a relatively small number of SKUs, about 20%, account for a high percentage of daily order volume, about 80%. That points to forward pick areas for fast movers, often in carton flow rack, where each light is used many times per shift.
Good fit. High pick density per location, small to medium items, stable slotting, and pick-and-pass zones where each picker covers a short run of lit locations.
Poor fit. Long tails of slow movers where most lights rarely turn on, large or bulky items, and layouts that change often.
Beyond order picking. MHI lists order picking, parts picking, sortation, kitting, consolidation, and assembly as applications.
For slow movers, RF scanning costs less to implement, so it is the more economical choice where lights would rarely turn on. To decide which SKUs earn a lit location in the forward area, see the warehouse slotting guide.
SKU fit check
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Pick to light vs put to light
Put to light runs the same idea in reverse. Instead of showing where to take items from, lights show where to put them. A worker scans an item from a batch-picked tote, and the light at the destination order location shows how many units to place there.
Put to light is common at put walls. In a setup research describes as widespread among online retailers, workers guided by put-to-light place items from batch-picked bins into a reach-through rack with shelves dedicated to individual orders, and packers on the other side pack completed orders. It is a common way to sort after batch picking. See the put wall guide for design details.
Benefits and limits
MHI says that in the right application, pick to light systems increase pick rate productivity and order accuracy. Independent evidence is thinner. A 2024 laboratory study comparing RF scanning, pick to light, and smart-glasses picking found pick to light had the shortest picking time per order line and the lowest perceived workload, and participants valued having both hands free. The study had 8 participants in a lab, so treat it as directional, not as a benchmark for your site.
Speed and accuracy. No reading or searching at the location, and the confirm button ties each pick to a specific slot.
Short training. Lights are simple to follow, which can shorten training for new and temporary staff at peak.
Hardware cost. The same study found light picking the most expensive of the three technologies to implement, because it must be mounted in each bin.
Rigidity. Lights are tied to locations. Re-slotting means remapping in software, and moving racks means moving hardware.
Travel is unchanged. Pick to light speeds the pick at the location but does not shorten the walk between locations. Zone design and slotting do that.
Fit call
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How to measure pick to light
Lines per labor hour. Compare the lit zone against the same zone on RF or paper, on the same order mix.
Picks per light per day. A utilization check. Lights that rarely turn on belong to slow movers that should move to a cheaper area.
Mispicks and short picks. Track by location to find lights, labels, or slots that cause errors. See the order picking accuracy guide.
Device uptime. A dead light or display stops picks at that location. Log failures and time to repair.
Site walkthrough
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Pick to light and robotics
Pick to light was built to guide people, so adding robots raises a practical question: what still needs a light? Autonomous mobile robots that bring totes to a lit zone pair well with it, because the person still picks and the robot handles the walking. Goods-to-person stations can use put to light to show which order tote gets each unit. A robot that picks for itself relies on its own perception rather than lights, so mixed areas need clear rules about which locations people and robots work.
Where Avatar fits
Pick to light is a strong choice for dense, fast-moving pick faces with stable slotting. Avatar targets a different case: its robots work in your existing racks, shelving, and bins and pick there, with no racking or layout changes. With Robots-as-a-Service, Avatar brings the hardware and you pay for output rather than buying robots or lighting every location. See where Avatar works on the Avatar solutions page.
How It Works
The process in four steps.
1
Launch the order
The picker scans a barcode on a tote or shipping container. Control software pulls the order from the WMS and lights every location in the zone that holds an item for it.
2
Follow the pick-to-light displays
The picker goes to a lit location, where a small display shows how many units to take. There is no list to read and no location label to search for.
3
Pick and confirm
The picker takes the units shown and presses the button on the light to confirm. The system records the pick, turns off the light, and updates the order.
4
Pass or close the tote
When no lights remain in the zone, the tote passes to the next zone or to packing, and the software sends the completed picks back to the WMS.
Frequently Asked Questions
What is pick to light?
Pick to light is a picking system that uses lights and small displays mounted at storage locations to show pickers where to pick and how many units to take. The picker confirms each pick by pressing a button, and the system moves on to the next lit location. It is also called pick-by-light or light-directed picking.
What is the difference between pick to light and put to light?
Pick to light shows a picker which storage location to take items from. Put to light shows a worker which order location to place items into, usually at a put wall after batch picking. Both use the same idea of a light, a quantity display, and a confirm button.
When is pick to light worth the investment?
It pays off where each light gets used often: fast movers with dense picks per location, stable slotting, and enough volume to keep pickers busy. MHI points to operations where about 20% of SKUs drive about 80% of order volume. For slow movers, RF scanning usually costs less to implement.
Does pick to light reduce picking errors?
It is designed to. Lights show the exact slot and quantity, and the confirm button ties each pick to a location, which removes reading and searching steps. MHI says pick to light increases productivity and order accuracy in the right application, but results depend on slotting, labeling, and keeping the lights maintained.
Sources
1. MHI (n.d.). Pick to Light. MHI Solutions Community, Solutions Guide. MHI.
2. Chondromatidis, N., Gialos, A., Zeimpekis, V., & Madas, M. (2024). Investigating the impact of completion time and perceived workload in pickers-to-parts order-picking technologies: Evidence from laboratory experiments. Logistics, 8(1), 13. MDPI.
3. Boysen, N., Stephan, K., & Weidinger, F. (2019). Manual order consolidation with put walls: The batched order bin sequencing problem. EURO Journal on Transportation and Logistics, 8(2), 169–193.
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