# Weeks of Supply (WOS) Report
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**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.
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## 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
| Metric | What It Tells You |
| ------------------------- | ----------------------------------------------- |
| 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:
* [ ] **Inventory is up to date.** Your on-hand quantities should reflect current warehouse stock, not stale numbers. If you are synced to a WMS, double-check the last sync timestamp
* [ ] **Your forecast is active and accurate.** A WOS report built on a flat or uncalibrated forecast will give misleading results. Make sure your forecast reflects current trends, seasonality, and any manual adjustments
* [ ] **Your lead times are set.** WOS is most useful when paired with lead time context — if a SKU has 10 weeks of supply but a 12-week lead time, that is a problem
## How to Build a WOS Report with Mo
**Time Required:** 5 minutes **Difficulty:** Beginner
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### 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.
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### 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.
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### 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.
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### Filter and Slice as Needed
Mo can cut this data multiple ways. Common follow-up asks include:
* "Show me only SKUs flagged as Low Stock"
* "Break this down by warehouse location"
* "Which SKUs in this list have an open PO already?"
* "Sort by WOS ascending so I can prioritize the most urgent ones"
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### Export or Share
Once you are happy with the view, export the report to share with your team, attach to a vendor meeting, or file for your weekly ops review.
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## How to Read Your WOS Report
| WOS Range | What It Means | Recommended Action |
| ---------- | ------------------------ | ----------------------------------------- |
| 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 |
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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.
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## 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.
## Related Guides
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[Mo Custom Reports](/analytics/reporting/mo-reports/mo-custom-reports.md)
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[Sales Velocity Report](/analytics/reporting/mo-reports/mo-standard-reports/sales-velocity-report.md)
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[Create a Replenishment or Allocation Plan](/planning-and-execution/replenishment/create-a-production-plan.md)
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[Forecasting](/planning-and-execution/forecasting.md)
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