Warehouse Putaway Optimization: Strategies That Actually Move the Needle
You've invested in faster receiving. Your dock-to-stock time is down. But when that inventory finally makes it to the floor, where does it go? For most warehouses, the answer is "wherever there's space" — and that decision costs more than anyone realizes.
Warehouse putaway optimization is the difference between inventory that's easy to find and inventory that turns every pick into a scavenger hunt. Get it right, and you compress travel time, reduce picking errors, and make better use of your cubic footage. Get it wrong, and you pay for it on every single order.
Why Putaway Deserves More Attention
Receiving gets the headlines. Picking gets the automation investment. Putaway sits in between, often treated as a simple task: take the pallet, put it somewhere, scan it. Done.
But that "somewhere" determines everything that happens next:
- Picker travel time: The average warehouse picker spends 50-60% of their shift walking. Where you put inventory determines how far they walk. A poorly slotted warehouse can add 2-3 miles per shift to every picker's route.
- Replenishment frequency: Put slow-moving SKUs in prime pick locations and you've wasted valuable real estate. Put fast-movers in the back and you'll be running replenishment constantly.
- Accuracy downstream: When similar products end up in adjacent locations, picking errors increase. When the same SKU lives in multiple random spots, cycle counts become unreliable.
One distribution center we've seen reduced total pick labor by 18% — not by changing their picking process, but by restructuring how and where they put inventory away.
The Three Putaway Strategies Worth Considering
1. Fixed Location Putaway
Every SKU has a designated home. Pallet of SKU-12345 arrives, it goes to aisle 4, rack B, level 2. Always.
When it works: Low SKU counts, stable product mix, and staff who know the warehouse well. Fixed locations are easy to learn and require minimal system sophistication.
When it fails: High SKU velocity changes, seasonal products, or space constraints. If SKU-12345's home is full, you need overflow logic — and overflow is where fixed systems get messy.
2. Dynamic (Chaotic) Putaway
Inventory goes wherever there's appropriate space. The WMS tracks location; operators don't need to memorize anything.
When it works: High SKU counts, variable inventory levels, and a WMS you actually trust. Dynamic putaway maximizes space utilization because you're not reserving empty slots for products that haven't arrived.
When it fails: Weak WMS discipline. If operators don't scan putaway locations accurately, or if the system allows the same SKU in too many places, you've traded space efficiency for inventory chaos.
3. Velocity-Based Slotting
Fast-moving SKUs go in prime locations (golden zone, near shipping). Slow-movers go high, low, or far. The system continuously re-evaluates based on actual movement data.
When it works: Any warehouse with measurable velocity differences between SKUs — which is nearly all of them. The Pareto principle applies: 20% of your SKUs typically generate 80% of your picks. Getting that 20% in the right spots has outsized impact.
When it fails: When you set it and forget it. Velocity changes. Seasonal products surge and fade. A slotting strategy needs regular review — quarterly at minimum, monthly for high-churn environments.
Practical Optimization Steps
Theory is nice. Here's what actually moves the needle:
Analyze Your Current State
Before changing anything, measure what you have. Pull 30 days of pick data and map it to your current slot locations. You're looking for:
- High-velocity SKUs in low-quality locations (far from shipping, bad ergonomics)
- Low-velocity SKUs occupying prime real estate
- SKUs with picks spread across multiple locations unnecessarily
This analysis alone often reveals 10-15% efficiency improvement just waiting to be captured.
Define Your Golden Zone
The golden zone is waist-to-shoulder height, close to your shipping area, on main travel paths. This is where your top 50-100 SKUs should live. Everything else is compromise.
Map your golden zone explicitly. Count the positions. Then rank your SKUs by pick frequency and assign accordingly.
Batch Your Putaway by Zone
Instead of putting away each receipt as a random walk through the warehouse, group putaway tasks by destination zone. One operator handles all putaway for aisles 1-5, another handles 6-10. Less travel, faster completion, fewer forklifts crossing paths.
Implement Directed Putaway
Your WMS — enhanced with tools like Sizelabs Warehouse Assistant — should tell operators exactly where to put inventory — not suggest, not offer options, but direct. The more decisions you remove from the putaway process, the faster and more consistent it becomes.
If your system offers multiple locations, configure it to recommend the optimal one first. If operators are constantly overriding recommendations, find out why and fix the root cause. AI-guided workflows can help bridge this gap by walking operators through the optimal putaway sequence step by step.
Review and Reslot Regularly
Slotting isn't a project; it's a process. Build a monthly review into your operations calendar:
- Which SKUs changed velocity significantly?
- Which locations have chronic overflow?
- Which picks are generating the most travel time?
Even 30 minutes of data review can identify re-slotting opportunities worth hours of weekly labor savings.
Measuring Putaway Optimization Success
Track these metrics before and after any changes:
- Putaway time per unit/pallet: How long does it take to get inventory from staging to its final location?
- Travel distance per put: Are operators walking less?
- Pick time per line: The ultimate downstream indicator — faster picks mean your slotting is working.
- Inventory accuracy: Better putaway should correlate with fewer cycle count discrepancies.
Where Automation Fits
Automated storage and retrieval systems (AS/RS), goods-to-person systems, and autonomous mobile robots can all transform putaway. But they're expensive, and they work best when layered on top of solid process fundamentals.
Before investing in hardware, exhaust your software and process improvements. A well-slotted warehouse with disciplined WMS execution often outperforms a poorly-configured automated one — at a fraction of the cost.
Putaway is where receiving hands off to the rest of your operation. The decisions made in those few minutes determine picker productivity for weeks. For e-commerce operations with high SKU counts and fast-changing velocity, getting putaway right is the difference between same-day shipping and perpetual backlog.
At Sizelabs, we help warehouses automate and optimize these critical transitions — because the details that happen between unloading and shipping are often where the biggest gains hide.
