> ## Documentation Index
> Fetch the complete documentation index at: https://docs.spherecast.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Weeks of Supply (WOS)

> How many weeks of forward demand your available inventory will cover

## What it tells you

Weeks of Supply (WOS) tells you how many weeks of upcoming demand your available inventory will cover before you run out. It is the same idea as [Days of Supply (DOS)](/dos), just measured in weeks instead of days, which many planners find easier to reason about for longer horizons.

It appears as two rows on the [Supply planning](/guide/supply-planning/overview) grid: **WOS - start** (coverage at the start of the period) and **WOS - end** (coverage at the end).

## How to read it

WOS uses the same color logic as DOS, comparing your available inventory against your **safety stock** (the buffer you want on hand) and your **excess threshold** (the top of the healthy range).

| Color      | What it means                                          |
| ---------- | ------------------------------------------------------ |
| Red        | Zero available inventory                               |
| Strong red | Below one-third of safety stock                        |
| Orange     | Between one-third of safety stock and safety stock     |
| Green      | Healthy: between safety stock and the excess threshold |
| Purple     | Excess: above the excess threshold                     |

For the full explanation of the color coding and the days-based fallback, see the [DOS](/dos) page.

Most teams show either DOS or WOS on the grid, not both, since they carry the same information at different resolutions. Pick whichever scale matches how you plan.

## What to do about it

The actions mirror DOS:

* **Red or orange:** order or expedite now to rebuild the buffer.
* **Green:** healthy, no action needed.
* **Purple:** overstocked, so defer, transfer, or reduce incoming orders.

## Example

A product shows **WOS - start** of 1 in orange against a safety-stock target of about 2 weeks. One week of coverage is below your buffer, so bring supply in before it runs down. A later period at 8 weeks in purple would tell you to ease off ordering instead.

> **Tip:** WOS and [DOS](/dos) are interchangeable views of coverage, so choose one for your grid. Pair it with [Available](/available) to see the underlying inventory.