How to calculate the full_amount of an item?

Consejo

Last updated on 2025-08-27.

The full_amount field for each line (item) must be calculated as follows:

full_amount = (unit_amount * quantity) + VAT

Example:

full_amount  = (16.52 * 3) + 10% VAT = 54.52

{
               "text": "Sombrero",
               "quantity": "3",
               "unit_amount": "16.52",
               "full_amount": "54.52",
               "system": {
                   "type": "REGULAR",
                   "category": {
                       "type": "VAT",
                       "rate": "10.0"
                   }
               }
           }

 

How are line-item discounts reflected in the full_amount calculation?

If discounts are applied at the item level, the calculation is performed as follows:

full_amount = ((unit_amount - discount) * quantity) + VAT

The discount is applied per unit, excluding VAT.

Example:

full_amount  = ((16.52 - 4.00) * 3) + 21% VAT = 45.45

For more details, see the article: How to apply a discount at the item level and globally 

{
               "text": "Sombrero",
               "quantity": "3",
               "unit_amount": "16.52",
               "full_amount": "45.45",
               "discount":"4.00",
               "system": {
                   "type": "REGULAR",
                   "category": {
                       "type": "VAT"
                   }
               }
           }