Small eBay sellers manage bin locations in Excel. It works — until it doesn't. The failure point is usually somewhere between 500 and 1,500 SKUs, and the symptoms are subtle: pickers hunting for items that "should" be in bin A-12 but are actually in B-7, restock queues that reference outdated locations, and slow onboarding of any warehouse helper because the spreadsheet is a jumble.
The Excel workflow that works
For sellers under 200 SKUs, a two-column spreadsheet is enough:
- SKU
- Bin location (e.g., A-12, B-7, C-3)
Print out weekly, tape to picking station. Update when you move items. Simple.
Where Excel starts breaking
Around 500 SKUs, three problems emerge:
Update lag. You move an item from A-12 to B-7 in the physical warehouse but forget to update the spreadsheet. Next pick fails, causing a "can't fulfill" cancellation. Metric damage.
Multi-location per SKU. Popular SKUs live in multiple bins (main stock + overflow + returns). Spreadsheet can't handle multi-location cleanly.
Concurrency. Two people can't edit the spreadsheet at once during picking. One person picks; the other watches.
The transition point
Practical threshold: 500-800 SKUs OR any situation with 2+ pickers OR multi-location per SKU. Above these, spreadsheet-based bin tracking causes more problems than it solves.
Below these thresholds, the added complexity of a WMS isn't worth the value. Keep the spreadsheet.
What to look for in a bin-tracking system
Minimum viable feature set:
- SKU → primary bin location (one per SKU by default)
- Multi-location support (a SKU in multiple bins with per-bin quantities)
- Bin-first search (given a bin, what SKUs are there?)
- Mobile access (pickers use phones, not desktops, on the warehouse floor)
- Transaction log (who moved what to where and when)
Bonus features that add real value:
- Barcode scanning integration
- Bin-utilization reporting (which bins are overfull / empty)
- Bin-hierarchy support (aisle → shelf → bin nested locations)
Software options by size
500-1,500 SKUs: Lightweight WMS bundled with your seller platform is usually enough. Look for tools with mobile-first bin picking.
1,500-5,000 SKUs: Dedicated inventory-management platforms (Inflow, Fishbowl, Ordoro). $100-300/month.
5,000+ SKUs: Full WMS (NetSuite WMS, ShipHero, Cin7). $500-2,000/month. Also, 3PL becomes viable at this scale.
Migration from spreadsheet
Two-week transition:
Week 1: Import spreadsheet into new system. Verify SKU → bin mapping. Fix any known outdated locations during import.
Week 2: Both systems run in parallel. Any update goes into both. Verify picking still works with new system's mobile UI.
Week 3: Retire spreadsheet. Full operation on new system.
Rushing the migration causes pick failures. Two weeks parallel keeps the safety net.
Bin naming convention
Consistent naming survives across scaling transitions. Recommended pattern: Zone-Aisle-Shelf-Bin.
Example: "A-3-2-4" means Zone A, Aisle 3, Shelf 2, Bin 4. Fits into a 4-character label. Scannable barcode fits easily on a bin.
Avoid location names like "the shelf near the door" or "big blue bin." Human-readable descriptions don't scale to new hires or barcode scanning.
Profitio's warehouse module includes bin locations, multi-location per SKU, and barcode scanning. 14-day free trial.