---
id: object/codeunit/398
type: object
title: Codeunit 398 "Sales Tax Calculate"
summary: Codeunit 398 "Sales Tax Calculate" in Base Application (Microsoft.Finance.SalesTax). 4 public procedures, 2 events. Present since at least BC23, still in BC30.
tier: official
language: en
tags:
  - codeunit
  - base application
versions:
  introduced: null
  last_changed: null
  deprecated: null
review:
  state: derived
  by: null
  at: null
  flags: []
generated:
  at: "2026-10-11T00:31:51.816Z"
  pipeline: 0.2.0
  prompts: {}
  input_hash: 231a79588705d2cb2999efd718261c4403c5989705644d256e9d99d76cafbff2
evidence:
  - kind: code
    url: https://github.com/microsoft/BCApps/blob/ea08af5ef2d6a9b5c5af4a029288abbe2c883220/src/Layers/W1/BaseApp/Finance/SalesTax/SalesTaxCalculate.Codeunit.al
    title: src/Layers/W1/BaseApp/Finance/SalesTax/SalesTaxCalculate.Codeunit.al (releases/29.x)
    date: null
    commit: ea08af5ef2d6a9b5c5af4a029288abbe2c883220
    t: null
    quote: null
links:
  learn: []
  objects: []
  features: []
  topics: []
  localizations:
    - localization/ca
    - localization/es
    - localization/mx
    - localization/us
  videos: []
  posts: []
  guidelines: []
object_type: codeunit
object_id: 398
name: Sales Tax Calculate
namespace: Microsoft.Finance.SalesTax
app: Base Application
extends: null
first_version: "23"
last_version: "30"
present_in:
  - "23"
  - "24"
  - "25"
  - "26"
  - "27"
  - "28"
  - "29"
  - "30"
changed_in: []
source_major: "29"
obsolete: null
countries:
  - ca
  - es
  - mx
  - us
ms_search_form_ids: []
counts:
  fields: 0
  procedures: 6
  events: 2
  subscribers: 0
relations:
  out: 0
  referenced_by: 0
  pages: 0
  extended_by: 0
  event_subscribers: 0
  calls: 0
  called_by: 7
  implements: 0
---

# Codeunit 398 "Sales Tax Calculate"

> Codeunit 398 "Sales Tax Calculate" in Base Application (Microsoft.Finance.SalesTax). 4 public procedures, 2 events. Present since at least BC23, still in BC30.

Base Application · Microsoft.Finance.SalesTax · BC23-30 · [source at ea08af5e](https://github.com/microsoft/BCApps/blob/ea08af5ef2d6a9b5c5af4a029288abbe2c883220/src/Layers/W1/BaseApp/Finance/SalesTax/SalesTaxCalculate.Codeunit.al) · facts from BC29

## Events published

- `OnBeforeCalculateTaxProcedure(TaxAreaCode: Code[20]; TaxGroupCode: Code[20]; TaxLiable: Boolean; Date: Date; Amount: Decimal; Quantity: Decimal; ExchangeRate: Decimal; var TaxAmount: Decimal; var IsHandled: Boolean)` (integration): Integration event raised before starting the main tax calculation procedure. Enables custom tax calculation logic or external tax service integration.
- `OnBeforeInitSalesTaxLines(var TaxAreaCode: Code[20]; var TaxGroupCode: Code[20]; TaxLiable: Boolean; Amount: Decimal; Quantity: Decimal; Date: Date; DesiredTaxAmount: Decimal; var TMPTaxDetail: Record "Tax Detail"; var IsHandled: Boolean; var Initialised: Boolean; var FirstLine: Boolean; var TotalForAllocation: Decimal)` (integration): Integration event raised before initializing sales tax lines for detailed calculations. Enables custom tax line initialization or external tax service integration.

## Procedures

- `CalculateTax(TaxAreaCode: Code[20]; TaxGroupCode: Code[20]; TaxLiable: Boolean; Date: Date; Amount: Decimal; Quantity: Decimal; ExchangeRate: Decimal): Decimal`: Calculates total sales tax amount for a transaction based on tax area and group codes. Handles multiple jurisdictions, tax-on-tax scenarios, and currency conversion.
- `ReverseCalculateTax(TaxAreaCode: Code[20]; TaxGroupCode: Code[20]; TaxLiable: Boolean; Date: Date; TotalAmount: Decimal; Quantity: Decimal; ExchangeRate: Decimal): Decimal`: Reverse calculates the net amount from a total amount including tax. Determines the base amount when given an amount that includes sales tax.
- `InitSalesTaxLines(TaxAreaCode: Code[20]; TaxGroupCode: Code[20]; TaxLiable: Boolean; Amount: Decimal; Quantity: Decimal; Date: Date; DesiredTaxAmount: Decimal)`: Initializes detailed sales tax lines for allocation across multiple tax jurisdictions. Prepares temporary tax detail records for posting and distribution calculations.
- `GetSalesTaxLine(var TaxDetail2: Record "Tax Detail"; var ReturnTaxAmount: Decimal; var ReturnTaxBaseAmount: Decimal): Boolean`: Retrieves the next sales tax line from initialized tax details for posting allocation. Returns individual tax jurisdiction amounts with proper rounding adjustments.

## Triggers

OnRun

## Called by

From the extracted call graph of BC29 (graphify-al on the snapshot checkout): calls whose target is known from a declared type or an `Object::"Name"` argument. Interface dispatch and calls through events are not counted, so the list is not complete.

- [Codeunit 12 "Gen. Jnl.-Post Line"](../codeunit/12.md) (4 calls: `InitVAT → CalculateTax`, `InitVAT → ReverseCalculateTax`, `PostVAT → GetSalesTaxLine`, …)
- [Table 5902 "Service Line"](../table/5902.md) (3 calls: `InitOutstandingAmount → CalculateTax`, `UpdateVATAmounts → CalculateTax`, `UpdateVATAmounts → ReverseCalculateTax`)
- [Table 290 "VAT Amount Line"](../table/290.md) (2 calls: `UpdateLines → CalculateTax`, `UpdateLines → ReverseCalculateTax`)
- [Table 37 "Sales Line"](../table/37.md) (2 calls: `UpdateVATAmounts → CalculateTax`, `UpdateVATAmounts → ReverseCalculateTax`)
- [Table 39 "Purchase Line"](../table/39.md) (2 calls: `UpdateVATAmounts → CalculateTax`, `UpdateVATAmounts → ReverseCalculateTax`)
- [Codeunit 57 "Document Totals"](../codeunit/57.md) (1 call: `CalculateSalesTaxForTempTotalPurchaseLine → CalculateTax`)
- [Codeunit 816 "Purch. Post Invoice"](../codeunit/816.md) (1 call: `CalculateVATAmounts → CalculateTax`)

## Across versions

- Present in: BC23-30
- Changed (declaration) in: none

## Countries that replace it

[CA](../../localizations/ca.md), [ES](../../localizations/es.md), [MX](../../localizations/mx.md), [US](../../localizations/us.md)

Source: AL metadata extracted from the code (names, ids, signatures, properties); no code bodies (D10).

## Ask your agent

Procedure bodies are not stored here (D10). The call sections above are our own, per object, from the BC29 call graph. For a procedure body or the calls of one procedure, ask bc-code-atlas (external, by Stefan Maron, MIT; default corpus w1-28), which the bc-observatory plugin connects: `bcatlas_resolve_node(object_type: "codeunit", object_name: "Sales Tax Calculate")`, then `bcatlas_get_procedure_body` or `bcatlas_get_neighbors` on the returned id.