Weeks of Supply (WOS) Report
Quick Answer: A Weeks of Supply (WOS) report shows how long your current inventory will last based on forecasted demand. It is calculated by dividing on-hand inventory by average weekly demand. In Moselle, Mo can build one in under 5 minutes from your live data.
What is Weeks of Supply?
Weeks of Supply (WOS) is an inventory planning metric that measures how many weeks your current stock will last at the current or forecasted rate of demand.
WOS is one of the most widely used metrics in supply chain and inventory management because it translates raw stock numbers into a time-based view that is easy to act on. A SKU with 1,000 units on hand sounds healthy — but if demand is 200 units per week, that is only 5 weeks of cover, which may be below your reorder threshold.
Why WOS Matters
Stockout prevention: Low WOS flags products that will run out before your next shipment can arrive
Overstock detection: High WOS reveals excess inventory tying up cash and warehouse space
Reorder timing: WOS paired with supplier lead times tells you exactly when to place your next order
Cash flow management: Understanding WOS across your catalog helps you allocate purchasing budget where it matters most
What Makes a Great WOS Report?
A great WOS report is not just a number. It gives you context — which SKUs are overstocked, which are at risk of stockout, and where you need to act now. The best WOS reports are:
SKU-level, not just brand-level averages
Channel-specific — DTC, wholesale, Amazon, etc. have very different velocity profiles
Forward-looking, based on your forecast — not just historical sales
Actionable, with clear flags for low WOS (under 4-6 weeks) and excess inventory (12+ weeks)
Key Metrics to Include
On-hand inventory (units)
Current stock available
Weekly forecasted demand
Expected rate of consumption
Calculated WOS
How many weeks current stock will last
Status flag
Low Stock, Healthy, or Overstock classification
Lead time comparison
Whether WOS covers the time needed to reorder
Before You Start: Make Sure Your Data Is Clean
A WOS report is only as good as the data behind it. Before pulling one, confirm:
How to Build a WOS Report with Mo
Time Required: 5 minutes Difficulty: Beginner
Open Mo and Set Your Context
Tell Mo what you are looking for. Be specific — the more context you give, the better your output. A strong prompt looks like:
"Can you pull a WOS report for all active SKUs in our DTC channel? I want to flag anything under 6 weeks and anything over 16 weeks."
You can also scope it to a product line, warehouse location, or time horizon.
Review the Output
Mo will return a SKU-level breakdown with:
On-hand inventory (units)
Weekly forecasted demand (units/week)
Calculated WOS (on-hand divided by weekly demand)
Status flags (e.g., Low Stock, Healthy, Overstock)
Scan the flags first. Your attention should go to the outliers — critically low WOS SKUs that need a purchase order, and high WOS SKUs that might be tying up cash.
Layer in Lead Times
Compare your WOS numbers against your supplier lead times. A SKU with 8 weeks of supply sounds healthy — but if your lead time is 10 weeks, you are actually already late. Ask Mo:
"Which SKUs have a WOS that's lower than their lead time?"
This is where the report goes from informational to truly actionable.
How to Read Your WOS Report
0-4 weeks
Critical — stockout risk
Expedite reorder immediately
4-8 weeks
Low — monitor closely
Confirm PO in pipeline
8-16 weeks
Healthy
No action required
16+ weeks
Excess — capital tied up
Consider promotion or pause future orders
Adjust these ranges based on your lead times and business model. A SKU with a 12-week lead time needs much earlier action than one you can reorder in 2 weeks.
Best Practices for WOS Reports
Use a rolling average for demand, not a single week. One unusually slow or fast week can throw your WOS calculation off. Use your forecasted weekly average for more stable results.
Account for committed inventory. If units are already allocated to open orders, they are not truly "on hand" for future demand. Build WOS based on available inventory (on-hand minus committed) when relevant.
Set WOS thresholds that make sense for your business. A food brand with a 2-week shelf life has very different thresholds than an apparel brand with seasonal buys. Your low/healthy/overstock bands should reflect your specific lead times, MOQs, and sell-through patterns.
Revisit your WOS report weekly. Demand shifts. Shipments arrive. The WOS snapshot you pulled on Monday looks different by Friday. Build it into your regular weekly rhythm.
Always compare WOS against lead times. A WOS number in isolation is incomplete. The question is always: do I have enough weeks of supply to cover the time it takes to get more stock?
Frequently Asked Questions
What is the formula for Weeks of Supply?
WOS is calculated by dividing your current on-hand inventory (in units) by your average weekly demand (in units per week). For example, 1,000 units on hand with 100 units/week demand equals 10 weeks of supply.
Should I use historical sales or forecasted demand for WOS?
Forecasted demand is preferred because it accounts for trends, seasonality, and planned promotions. Historical averages can be misleading if demand is changing.
How often should I run a WOS report?
Weekly is the recommended cadence. Demand and inventory levels shift constantly, so a regular cadence keeps your reorder decisions grounded in current data.
What is a good WOS target?
It depends on your lead times and business model. A common healthy range is 8 to 16 weeks, but brands with shorter lead times may target 4 to 8 weeks, while those with long overseas lead times may need 12 to 20 weeks of cover.
Can I build a WOS report by channel or warehouse?
Yes. Specify the scope in your prompt to Mo (e.g., "DTC channel only" or "break down by warehouse location") and Mo will tailor the report accordingly.
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