> ## 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.

# Days of Supply (DOS)

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

## What it tells you

Days of Supply (DOS) tells you how many days of upcoming demand your available inventory will cover before you run out. If a product has a DOS of 12, you have roughly twelve days of selling left at the expected pace of demand, based on the inventory you can actually use to meet it.

It appears as two rows on the [Supply planning](/guide/supply-planning/overview) grid: **DOS - start** (the coverage at the start of the period) and **DOS - end** (the coverage at the end, after that period's demand and supply play out). Watching both tells you whether your buffer is growing or shrinking across the period.

## How to read it

DOS is color-coded so you can scan a product's health at a glance. By default the color keys off your available inventory compared with your **safety stock** (the buffer you want to keep 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                     |

There is also a simpler days-based fallback where a very low number of days shows red and a very high number shows purple, used when the inventory-based coloring does not apply.

Where DOS cannot be computed, you will see **n.a.** For example, after a product's discontinuation date there is no forward demand to cover, so the value is not available.

## What to do about it

* **Red or orange (low coverage):** you are at or heading toward a stockout. Order now, or expedite an open order, to rebuild the buffer before it runs dry.
* **Green:** healthy, no action needed.
* **Purple (excess):** you are overstocked. Consider deferring or reducing incoming orders, or transferring the surplus to a location that needs it.

## Example

A product shows **DOS - start** of 6 in orange. Your safety stock target is about 10 days of coverage, so 6 days sits below the buffer you want. That orange cell is your cue to pull in supply before the buffer erodes further. If the next period showed purple at 40 days, you would instead look to slow orders down.

> **Tip:** DOS and [WOS](/wos) (Weeks of Supply) measure the same thing on different scales. Pair DOS with [Available](/available) to see the inventory behind the number, and check [Shortage](/shortage) when coverage drops to zero.