Why Is My BigCommerce Inventory Always Wrong? Common Causes and Fixes
BigCommerce says you have 30 units. Your warehouse has 10. A customer just ordered 12, and now you're scrambling to figure out whether you can actually fulfill it. Sound familiar?
Inventory discrepancies are one of the most common operational problems for growing BigCommerce stores, and the frustrating part is that there's rarely a single obvious cause.
At Stellar One, we regularly work with BigCommerce businesses that have hit this wall. The good news is that the causes are well-understood and fixable. In this article, we'll walk through the five most common reasons for BigCommerce inventory inconsistencies and what you can do about each one.
The 5 Most Common Causes of BigCommerce Inventory Errors
Not every inventory problem has the same root cause, but the following five causes are the ones we see most often in growing BigCommerce stores.
1. Your Storefront and Your Back Office Aren't Connected
This is the most common cause by far. If you're running BigCommerce alongside QuickBooks, a spreadsheet, or any tool that doesn't automatically sync with your store, your inventory numbers will drift apart almost immediately.
Every time someone in the warehouse receives a shipment, processes a return, or adjusts stock without also updating BigCommerce, the gap will widen. The more orders you process, the faster those numbers will diverge.
2. You're Selling on Multiple Channels Without Centralized Inventory
If you sell on BigCommerce, Amazon, eBay, and a wholesale channel, you probably know that each platform tracks its own inventory independently. A sale on Amazon won't automatically reduce your BigCommerce stock count unless something is connecting the two.
Without a centralized inventory system allowing multichannel order management, multichannel selling almost guarantees overselling and stock discrepancies.
3. Returns Aren't Updating Your Stock Counts
When a customer returns a product, the refund might get processed in BigCommerce, but the inventory adjustment often requires a manual step.
If your team doesn't consistently restock returned items in the system, your available quantities will undercount what's actually on the shelf. Over time, this issue will create a growing gap between what you think you have and what you actually have.
4. Manual Data Entry Errors Are Compounding
If anyone on your team is manually entering inventory adjustments, receiving shipments by updating a spreadsheet, or typing stock counts into BigCommerce by hand, errors are inevitable.
A mistyped quantity here, a missed entry there. Each one is small on its own, but they compound quickly. By the end of the month, your numbers can be significantly off without any single obvious mistake to point to.
5. Your Warehouse Operations Aren't Reflected in Real time
Physical warehouse activity, like picking, packing, and shipping, changes your actual inventory. But if those activities aren't recorded in a system that talks to BigCommerce in real time, your storefront will show quantities that don't reflect what's currently happening on the warehouse floor. This is especially problematic during high-volume periods when dozens of orders are being picked simultaneously.
How to Fix BigCommerce Inventory Accuracy Problems
The fixes depend on the severity of the problem and the stage of your business:
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If your discrepancies are small and occasional, start by tightening your processes. Run physical inventory counts more frequently. Create a clear procedure for how returns get restocked in the system. Audit who has access to make manual inventory adjustments and when those adjustments happen. Better processes can close the gap if your order volume is still manageable.
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If your discrepancies are persistent and growing, the root cause is likely that your systems aren't connected. BigCommerce tracks storefront inventory. Your accounting tool tracks financial transactions. Your warehouse tracks physical stock. But none of them are talking to each other automatically, and your team is the manual bridge filling the gaps. At a certain volume, that bridge breaks.
The long-term solution is connecting your BigCommerce store to a back-office system that manages inventory, orders, and financials in one place.
An ERP platform with a native BigCommerce connector will sync inventory in real time: When an order comes in through BigCommerce, the system will automatically allocate that inventory so it can't be sold elsewhere. When the warehouse ships it, the count will decrement. When a return comes back, the stock will adjust. No manual entries, no spreadsheets, no drift.
Keep Your BigCommerce Inventory Accurate as You Grow
Are your inventory numbers off more often than they're right? Most growing BigCommerce stores hit this exact problem once they start selling across multiple channels or processing more than a few hundred orders a month. The storefront was built to sell, not to manage the operational complexity behind the sale.
The real cost isn't just the occasional canceled order or frustrated customer. It's the hours your team spends every week reconciling numbers that should match but don't, and the decisions you can't make confidently because you don't trust your data. Those costs grow in proportion to your order volume, meaning the longer the problem persists, the more expensive it becomes.
If your discrepancies are still occasional and manageable, tightening your processes may be enough for now. But if they're persistent and getting worse, our article on the signs you've outgrown BigCommerce's built-in tools can help you evaluate whether it's a process problem or a systems problem, and what your options are from there.
Not sure if your business is ready for a system upgrade? Take our ERP Readiness Quiz to find out where you stand.