Why Shopify and your 3PL show different inventory numbers

Name the state behind each number

Shopify distinguishes available, committed, unavailable, and incoming inventory. Ask your warehouse management system, or WMS, which quantities map to those states. A screen labeled “stock” may include units that cannot be sold. Build a small mapping table for each system, including damaged units, quality holds, and orders already allocated. Use the platform documentation as the starting definition, then confirm the integration’s actual mapping.

Take snapshots at the same time

Choose one SKU, one warehouse, and one reporting timestamp. Export transaction history covering the interval around the discrepancy. Check whether the connector uses queued updates and whether an error requires manual intervention. Comparing a current warehouse count with yesterday’s storefront export creates noise. Start narrow enough that a person can trace every movement rather than aggregating the entire catalog immediately.

Reconcile a small example

Illustrative example: the warehouse has 100 units physically present. Twenty are committed to open orders and five are unavailable pending inspection. If the systems use matching definitions, 75 may be available to sell. A storefront showing 75 and a warehouse showing 100 on hand are not necessarily in conflict. If Shopify shows 85 available, the next question is which ten-unit transaction or state change is missing.

Fix the mapping, not just the displayed quantity

A manual adjustment can make dashboards match temporarily while hiding a repeated synchronization issue. Ask who owns the connector, where errors are visible, and how retries avoid duplicate updates. Run a controlled receipt, order, cancellation, and adjustment after any mapping change. Record the expected state at each step and confirm both systems before applying the fix more broadly.