Unit of Measure Conversions
The Unit of Measure Conversions page is a general-purpose lookup table that stores conversion ratios between units of measure of the same dimension – for example, weight-to-weight (kg↔g) or volume-to-volume (l↔ml). You cannot mix dimensions on this page (for example, you cannot enter kg→l here; that relationship is item-specific and must be entered on the item instead).
These entries enable automatic calculation of the Net Weight, Recipe Weight, and Density fields on items whenever a unit of measure is added or modified on the item.
How Entries Work
Each row in the page links two units of measure with a quantity ratio. The Conversion Factor is calculated automatically from the quantities you enter.
| Field | Description |
|---|---|
| From Qty. per Unit of Measure | The quantity of the source unit in the relationship. |
| From Unit of Measure Code | The source unit of measure. |
| To Qty. per Unit of Measure | The equivalent quantity in the target unit. |
| To Unit of Measure Code | The target unit of measure. |
| Conversion Factor | Calculated automatically as To Qty. ÷ From Qty. |
You only need to enter a pair in one direction. For example, enter KG → G with quantities 1:1000. If the inverse (G → KG) is needed, the reverse record is looked up automatically.
Note
You cannot enter both KG→G and G→KG. An error is shown if the duplicate direction is entered.
Examples
1 Kilogram = 1000 Gram → enter From: 1 KG, To: 1000 G
1000 Meter = 1 Kilometer → enter From: 1000 M, To: 1 KM
Automatic Calculation of Item Data
The main purpose of the Unit of Measure Conversions page is to enable automatic calculation of item master data fields when the item's assigned units of measure differ from the reference units configured in Process Manufacturing Setup.
The Process Manufacturing Setup page defines two reference units:
- Weight Unit of Measure – the unit used as the base for Net Weight across all items (for example, KG).
- Volume Unit of Measure – the unit used together with the weight unit to calculate density (for example, L).
Net Weight and Recipe Weight
When you add or change an item's Base Unit of Measure or an item unit of measure, a path is searched from any of the item's units of measure to the Weight Unit of Measure in the Process Manufacturing Setup page. The Unit of Measure Conversions page is used to find the conversion factor. If a match is found, an updated Net Weight and Recipe Weight is proposed on the item.
For example, the setup Weight Unit of Measure (UoM) is KG and an item's unit of measure is G. If a conversion entry G↔KG exists, the Net Weight is calculated as 1 / Qty. per UoM × conversion factor and an update is offered on the item.
Density
Density is always item-specific and represents weight per volume unit. It is calculated as:
Density = Net Weight × Qty. per Volume UoM ÷ Conversion Factor
The Unit of Measure Conversions page is used here to convert between a volume unit assigned to the item and the setup's Volume Unit of Measure – for example, if the item has L and the setup uses ML.
Note
The weight-to-volume relationship itself (for example, 1 KG = 2.7 L) is not entered on this page. It must be maintained on the item directly, because it is substance-specific. Entries on this page are only needed when the item's volume unit of measure does not directly match the Volume Unit of Measure configured in Process Manufacturing Setup.
Density Examples
Density = kg / l (Weight UoM = KG, Volume UoM = L)
Density = g / cm³ (Weight UoM = G, Volume UoM = CM³)
Triggers for Automatic Calculation
The automatic recalculation runs in the following situations:
| Trigger | Calculates |
|---|---|
| Base Unit of Measure changed on item | Net Weight, Recipe Weight, Density |
| Qty. per Unit of Measure changed in Item Units of Measure | Net Weight, Recipe Weight, Density |
| Update Item Net Weights report (from the Unit of Measure Conversions page via Actions > Functions) | Net Weight and/or Density in batch for all or filtered items |
If an existing value is already present on the item, confirmation is requested before overwriting it. In batch mode, the update runs without confirmation.
Example: Olive Oil Item Setup
This example shows how to set up an item for olive oil so that the Density field on the Item Card shows 0.918, given:
- Olive oil density: 0.918 g/mL = 0.918 kg/L
- 1 kg of olive oil = 1.08932 L (item-specific weight-to-volume relationship)
Process Manufacturing Setup
| Field | Value |
|---|---|
| Weight Unit of Measure | KG |
| Volume Unit of Measure | L |
Scenario A: Item has L as a unit of measure (no conversion entry needed)
This is the simplest and recommended approach. The item already has L as one of its units of measure, which directly matches the setup's Volume UoM.
Item Units of Measure
| Code | Qty. per Unit of Measure | Meaning |
|---|---|---|
| KG | 1 | Base unit |
| L | 0.918 | 1 L of olive oil weighs 0.918 kg |
When you save the L row, the calculation runs automatically:
Density = Net Weight × Qty. per L = 1 × 0.918 = 0.918
The Density field on the Item Card is updated to 0.918. No entry in the Unit of Measure Conversions page is required, because the item's unit of measure directly matches the setup's Volume UoM.
Note
The Net Weight is also automatically set to 1 because the item's Base Unit of Measure (KG) already matches the setup's Weight UoM.
Scenario B: Item only has mL as a volume unit of measure (conversion entry required)
If the item's volume unit of measure is mL instead of L (which does not match the setup's Volume UoM of L), density cannot be calculated directly. The Unit of Measure Conversions page is used instead to bridge the gap.
Unit of Measure Conversions
| From Qty. | From UoM | To Qty. | To UoM | Conversion Factor |
|---|---|---|---|---|
| 1 | L | 1000 | ML | 1000 |
Item Units of Measure
| Code | Qty. per Unit of Measure | Meaning |
|---|---|---|
| KG | 1 | Base unit |
| ML | 0.00092 | 1 mL of olive oil weighs 0.00092 kg |
Because L is not directly assigned to the item, each of the item's other units of measure is checked against the Unit of Measure Conversions page. The L→ML entry is found, and the inverse factor 1 ÷ 1000 = 0.001 is applied.
Density = (Net Weight × Qty. per ML) ÷ Factor = (1 × 0.00092) ÷ 0.001 ≈ 0.918
The Density field on the Item Card is updated to 0.918. Although the displayed Qty. per Unit of Measure is rounded to 5 decimals (0.00092), Business Central uses its full internal precision for the density calculation, which yields the same result as Scenario A. The entry on the Unit of Measure Conversions page is what enables the calculation.
Recipe and Production Structure Quantities
The Unit of Measure Conversions page is also used during recipe and production structure quantity calculations. When a production structure's content is specified as Mass % or Volume Share %, the setup's Weight or Volume UoM is converted to the production structure's unit of measure using this page to determine the actual component quantity. For more information, see Dispensing Development Tools.
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