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

# Unit of measure conversions

> Buy parts in the supplier's pack quantity while stocking and consuming them in the unit your floor uses.

A unit of measure (UOM) conversion lets you buy in the supplier's unit while stocking and consuming in your floor's unit. For how the conversion flows across purchasing, receiving, and inventory, see the [Purchasing overview](/manage-supply-chain/purchasing/overview#unit-of-measure-conversions).

Three units commonly coexist on a purchase:

| Unit         | What it's for                                                               |
| ------------ | --------------------------------------------------------------------------- |
| Stock UOM    | How the part is tracked in inventory and consumed on a BOM, such as `feet`. |
| Purchase UOM | How the supplier sells it, such as `roll`.                                  |
| Cost UOM     | The unit the unit cost is expressed in, such as per `roll`.                 |

## Configure a conversion

A conversion lives on the supplier part number; the link between an ION part and a specific supplier's SKU. The same part can come from two suppliers in two pack quantities, so each conversion is stored independently.

1. In ION, open the part in the **Parts Library**.
2. Open the **Suppliers** section on the part.
3. Click **Add Supplier Part** to open the **Create Supplier Part** dialog, then provide:
   * **Supplier**: pick from your supplier list.
   * **Supplier Part Number**: the supplier's SKU.
   * **Supplier Part Units**: the unit the supplier ships in.
   * **Unit of Measure Conversion Factor**: how many stock-UOM units are in one supplier-UOM unit.
4. Save.

To manage the list of available units, see [Manage units of measure](/administration/supply-chain-settings/manage-units-of-measure).

## On a purchase order

1. Add the ION part to a PO line. ION offers a **Supplier Part** picker, populated from that part's supplier part numbers for the PO's supplier.
2. Pick the supplier part. The line switches into the supplier UOM.
3. Enter the quantity in the supplier UOM.
4. Enter the unit cost in the supplier UOM.

If you don't pick a supplier part, the line falls back to the stock UOM. The **On Order** inventory ION creates is recorded in the stock UOM (500 feet, On Order) even though the line shows 5 rolls.

## On receiving

1. The receiver opens the receipt for the PO. The receipt line shows the supplier UOM.
2. As each unit is received, ION applies the conversion.
3. The resulting inventory carries the stock UOM.

## Changing a conversion

When a supplier changes pack quantity, for example from 100-foot rolls to 250-foot rolls, create a new supplier part number with the new conversion factor rather than editing the old one.
Old POs reference the old supplier part number and need its conversion to reconcile correctly. ION does not re-apply a changed conversion to receipts already received.

## Related

* [Manage units of measure](/administration/supply-chain-settings/manage-units-of-measure)
* [Receive parts](/manage-supply-chain/receiving/receive-parts)