Understanding Retail Weeks of Supply
How we calculate. WOS = inventory ÷ average weekly sales. See our methodology and accuracy policy .
Real-world scenario: A typical Retail Weeks of Supply case uses inventory 1200 and average weekly sales 150. Enter the same figures below to reproduce the worked path.
What is Retail Weeks of Supply?
An inventory coverage KPI in weeks. Distinct from logistics inventory days of supply and from stock-to-sales ratio.
- Same UOM for inventory and weekly sales (units or $)
- Weekly sales = average run rate
- Label retail vs cost dollars
The Formula
Worked Example
Common Use Cases
- Replenishment: coverage checks
- Markdown timing: excess weeks
- Open-to-buy: WOS vs target
Pro Tips
- Don’t use Logistics days-of-supply for store WOS
- Freeze seasonal run-rate windows
- Pair with sell-through
| Scenario | When to use |
|---|---|
| Percent of a number | Finding a part of a whole (tax, tip, score) |
| Percent change | Comparing old vs new values |
Limitations: Retail Weeks of Supply results are educational retail merchandising aids—not accounting, tax, or inventory-system advice. Confirm definitions with your POS, ERP, and brand reporting standards.
Common mistakes
- Swapping part and whole: The denominator must be the full total, not a subset.
- Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
- Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.
The worked example for retail weeks of supply was verified with the calculator form on this page—enter the same values to confirm the result.
When to use this calculator
- Use this page when your wording matches retail weeks of supply and the form labels on screen.
- Use percent of a number for “what is X% of Y?” problems.
- Use number is what percent when you know part and whole and need the percent.
Still unsure about retail weeks of supply? Start with the quick answer above, then open the linked calculator that matches your wording.
❓ Frequently Asked Questions
How do I use this retail weeks of supply calculator?
For retail weeks of supply, enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.
What formula does this page use?
See the quick answer and formula box above for retail weeks of supply—the same percentage calculator expression is applied to your inputs.
What if my result looks wrong?
When checking retail weeks of supply, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.
Authoritative References
For retail merchandising and store performance concepts, consult:
- National Retail Federation — retail industry context
- Retail Council — retail operations resources
- Shopify Blog — ecommerce and retail KPI explainers