Tracking ecommerce inventory manually in spreadsheets: risks and remedies
Many ecommerce teams begin inventory control with spreadsheets because they are familiar and quick to set up. As order volume, channels, and warehouse locations grow, spreadsheet-led tracking becomes a bottleneck that affects fulfilment speed, stock accuracy, and purchasing decisions.
By Darren ArdenerUpdated
Co-founder of Just Applications Ltd, the team behind Adlixor
The Challenge
Spreadsheet inventory relies on people to enter receipts, adjustments, and sales at the right time and in the right format. This creates delays and mismatches between available stock, stock on hand, and stock allocated to orders, leading to overselling, backorders, and excess safety stock. Version confusion, inconsistent SKU naming, and manual formula errors make it hard to trust the numbers during peak periods.
The Solution
A systematic approach uses a single source of truth for SKUs, stock locations, and movements, with automated updates from sales channels and warehouse activities. Stock is reserved when orders are placed, decremented when items are picked and despatched, and incremented when purchase orders are received. Controls such as validation rules, audit trails, and low-stock alerts reduce errors and make replenishment decisions based on timely, consistent data.
Step-by-Step Guide
- 1
Document your current inventory workflow, including when stock is received, adjusted, allocated, picked, packed, and despatched.
- 2
Create a definitive SKU catalogue with unique identifiers, unit of measure, barcodes, and variant attributes, and map every spreadsheet SKU to it.
- 3
Define inventory locations and states such as on hand, allocated, available, quarantined, and in transit, and decide which states count as sellable.
- 4
Clean and reconcile existing stock figures by running a cycle count on fast-moving items and a full count on the remainder.
- 5
Set rules for when stock changes occur, such as allocating stock at order import and decrementing stock at pick confirmation rather than at label printing.
- 6
Integrate order sources so that sales, cancellations, refunds, and edits synchronise consistently with the inventory record.
- 7
Implement receiving and put-away steps that capture purchase order quantities, shortages, and damages at the point of receipt.
- 8
Configure reorder points and lead times per SKU and supplier, and set up alerts and replenishment reports based on sales velocity.
- 9
Run parallel checks for a short period, comparing system stock movements to physical counts, and resolve discrepancies before retiring the spreadsheet.
Pro Tips
- ✓Standardise SKU formats and forbid free-text product naming to avoid duplicate items that look similar but behave differently in reports.
- ✓Track adjustments with reason codes such as damage, shrinkage, mis-pick, or supplier shortfall so you can address root causes.
- ✓Separate on hand from available stock and always account for allocations to open orders and holds.
- ✓Use cycle counts for the top sellers weekly and medium sellers monthly to reduce disruption compared with infrequent full stocktakes.
- ✓Record pack sizes and minimum order quantities to avoid purchasing errors when suppliers sell in cases rather than single units.
- ✓Set a cut-off time for same-day despatch and ensure stock allocation occurs before that cut-off to reduce last-minute substitutions.
Frequently Asked Questions
- Why do spreadsheets become unreliable for inventory tracking?
- They depend on timely, accurate manual updates across multiple events such as receipts, adjustments, and sales. As volume grows, delays, duplicate versions, and formula mistakes cause the spreadsheet to drift from physical stock.
- What is the difference between stock on hand and available stock?
- Stock on hand is the physical quantity present in a location. Available stock is what can be sold after subtracting allocations to open orders, holds, and other non-sellable states.
- When should stock be decremented in the fulfilment process?
- For accuracy, decrement when picking is confirmed or when goods leave the warehouse, not when an order is created. Pair this with allocation at order placement to prevent overselling.
- How do I prevent overselling across multiple sales channels?
- Use centralised inventory with frequent synchronisation to all channels and reserve stock as soon as orders are accepted. Also account for channel-specific latency by keeping a small buffer on high-risk SKUs if updates are not immediate.
- How should returns affect inventory numbers?
- Returns should move into a separate state such as inspection or quarantine until condition is verified. Only then should items be returned to available stock, written off, or moved to refurbished stock.
- What are the first metrics to monitor after moving away from spreadsheets?
- Start with stock accuracy rate from cycle counts, oversell rate, backorder rate, and the time from receipt to availability. Monitor adjustment volume by reason code to spot process issues.
Related Guides
Further reading from our blog
- BlogHow to Manage Inventory Across Multiple Channels Without OversellingOverselling on one channel because another sold your last unit is one of the most damaging mistakes a multichannel seller can make. Here is how to prevent it.
- BlogThe Complete Multichannel Ecommerce Guide for UK Sellers in 2026Everything UK ecommerce sellers need to know about selling across multiple channels — from choosing the right marketplaces to managing inventory, orders and fulfilment at scale.
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