> For the complete documentation index, see [llms.txt](https://docs.flowlity.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.flowlity.com/concepts/stock-min.md).

# How Flowlity calculates Stock Min

**Stock Min** (shown as the **Flowlity Min** line in the [Planning](/modules/planning.md) module) is the dynamic safety stock Flowlity holds to protect availability against demand variability and supply uncertainty. It is the lower bound of the [optimal stock corridor](/concepts/buffer-policies.md).

Unlike a classic safety stock, which is a single static value derived from average demand and a fixed lead time, Flowlity's Stock Min is **recomputed for every future period**. It rises when the coming weeks are riskier (higher or more volatile demand, longer or less reliable supply) and falls when they are calmer, so you carry protection only where and when it is actually needed.

{% hint style="info" %}
We do not publish the exact formula. This page explains the concept and the data points that feed it, so you can understand why the Flowlity Min line moves the way it does.
{% endhint %}

### The core idea

To cover a product between today and the next delivery, Flowlity needs to answer two questions with uncertainty on both sides:

* **How much could demand be?** Not just the average, but a realistic high case.
* **How long could resupply take?** Not just the nominal lead time, but a realistic worst case.

Flowlity models both as **probability distributions** rather than single numbers, then sizes Stock Min to cover the gap between an expected scenario and a high-risk scenario over the replenishment period. The width of that gap, tuned to your target service level, is the safety stock.

### Data points Flowlity uses

Flowlity combines several signals, all computed per product and per site:

**Demand signals**

* **Historical demand**: past consumption, including its level and its variability.
* **Probabilistic demand forecast**: Flowlity's [forecast](/concepts/demand-forecasting.md), expressed as a range of likely outcomes rather than a single line, including the high-demand case.
* **Forecast accuracy**: how well the model has predicted this product recently. A product that is harder to forecast gets more protection.
* **Demand variability**: how erratic consumption is from period to period.

**Supply signals**

* **Historical lead time**: how long resupply has actually taken in the past.
* **Probabilistic lead time**: the expected lead time and, crucially, its variability, so that unreliable supply is buffered more than dependable supply.
* **Supplier reliability signals**: inputs such as supplier scorecards and carrier performance that inform how much lead time can drift.

**Policy and context signals**

* **Target service level**: the availability objective you set per product or strategy (for example 95%). A higher target widens Stock Min.
* **Risk profile**: a product-level risk setting that scales protection up or down for critical or low-priority items.
* **Product lifecycle stage**: new products, running products, and end-of-life products are treated differently.
* **Minimum floor**: an optional threshold (in quantity or days of coverage) that Stock Min will never drop below. See [Buffer policies and safety stock](/concepts/buffer-policies.md).

### Why it is dynamic

Because the demand forecast and the lead-time model are both time-dependent, Stock Min changes across the horizon:

* Ahead of a seasonal peak or a promotion, the high-demand case rises, so Stock Min rises with it.
* When supply becomes more reliable, the lead-time buffer shrinks and Stock Min drops.
* As forecast accuracy improves for a product, less protection is needed for the same service level.

This is what lets Flowlity protect availability while keeping average inventory lower than a static safety stock would require.

### Where Stock Min applies

Stock Min is calculated for make-to-stock strategies that use Flowlity's AI (for example **MTS Flowlity AI**). Strategies with a fixed minimum or a manual reorder point use the value you set instead of a dynamically computed one, and **MTO** products carry no Stock Min. See [Inventory strategies](/concepts/inventory-strategies.md) for the full list.

### Related pages

* [Buffer policies and safety stock](/concepts/buffer-policies.md): The Flowlity Min/Max corridor and where to configure buffers.
* [Inventory strategies](/concepts/inventory-strategies.md): Which strategies use a dynamic Stock Min.
* [Demand forecasting explained](/concepts/demand-forecasting.md): How the probabilistic forecast is built.
* [Configure your inventory strategy](/how-tos/configure-inventory-strategy.md): Step-by-step setup.
* [Planning](/modules/planning.md): Where the Flowlity Min line is shown.