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title: "Specifying the Unit Cost More Precisely"
canonical: "https://docs.rubiconwater.com/space/BNC/1990034242/Specifying%20the%20Unit%20Cost%20More%20Precisely"
format: markdown
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When you create a charge, you must specify the **Amount** for the charge. For calculated and variable charge types, this is the unit cost for an item. The unit cost is multiplied by the quantity (either specified or read from the database) to give the actual cost of the item.

The Amount can only be specified to two decimal places. To work around this limitation, you can multiply the amount by a factor of ten, and specify the multiplier in the Charge Factor field. When the cost is calculated, it will first be multiplied by the **Amount**, then divided by the **Charge Factor** to give the correct charge with the required accuracy.

> ℹ️ **Example**
> ℹ️ 
> ℹ️ To use a unit cost of $0.0067, multiply by 100 to give $0.67
> ℹ️ 
> ℹ️ - Enter 0.67 in the **Amount** field.
> ℹ️ - Enter 100 in the **Charge Factor** field
> ℹ️ 
> ℹ️ The quantity is first multiplied by 0.67, then divided by 100 to give the cost.

**To specify the unit cost more accurately:**

1. In the Charges module select the charge whose charge factor you want to set and click **Edit**. (You can also set these fields when you are creating a new charge)
2. In the **Amount** field, multiply the unit cost by a sufficient factor that there are only two digits after the decimal point.
3. In the **Charge Factor** field, enter the multiplier that you used for the Amount.
4. Click **Save** to save your changes.

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