Multi-Location Inventory Management: How to Track and Optimise Stock Across Multiple Warehouses

The multi-location inventory visibility problem#

When inventory is spread across multiple locations — your own warehouse, Amazon FBA, a retail store, and perhaps a 3PL — each system reports only its own stock position. Your Shopify inventory shows warehouse stock. Amazon Seller Central shows FBA stock. Your retail POS shows store stock. None shows total stock across all locations for any given SKU. The result: you might reorder a product because your warehouse shows it at reorder point, not realising you have 200 units sitting in Amazon FBA that are moving slowly. The reorder creates an overstock situation that was invisible when the decision was made.

Stock allocation across channels: the optimisation problem#

Multi-location inventory management requires active allocation decisions — deciding how to distribute stock across channels to maximise overall sell-through while maintaining appropriate service levels in each channel. A product that sells 40 units per month through Shopify and 10 units per month through Amazon should not have an equal split of stock between the two channels. Stock should be allocated proportionally to sales velocity by channel — and this allocation should be continuously reviewed as velocity patterns change.

Transfer costs: the hidden expense of rebalancing stock#

Moving stock between locations is not free. Withdrawing stock from Amazon FBA incurs removal order fees (currently approximately £0.97 per item for standard size). Transferring between 3PLs or from warehouse to store incurs transport costs. These transfer costs should be factored into the decision of whether to rebalance — sometimes it is more cost-effective to run out of stock in one location and replenish from new inbound stock than to pay removal and transfer costs to rebalance existing inventory.

The minimum viable multi-location inventory system#

The minimum viable system for managing multi-location inventory is a master inventory spreadsheet (or inventory management software) that aggregates stock positions from all locations into a single view by SKU — updated at least weekly. Each row shows: SKU, units in own warehouse, units at FBA, units in retail, total units across all locations, weekly sales velocity total, and weeks of cover based on total units. This single view reveals both oversupply in specific channels and total inventory health — the two most important insights for optimising working capital and preventing both stockouts and overstock.

How AskBiz provides unified multi-location inventory visibility#

AskBiz connects to your Shopify inventory, Amazon FBA inventory, and other data sources to build a unified inventory view by SKU across all locations. It shows total units, total weeks of cover, and the breakdown by location — identifying products where stock is misallocated (too much in one location relative to its sales velocity there) and products where total stock across all locations is below the reorder point even if individual locations show adequate stock. Ask it: what is my total inventory position for Product X across all channels, which products are overstocked at Amazon FBA but understocked on Shopify relative to sales velocity, which products need reordering when total stock across all locations is considered.