---
title: "Top-up Tax / QDMTT Calculator"
method: POST
path: "/v1/tools/topup_tax_qdmtt_calculator"
tags: ["pillar-two", "globe", "top-up-tax", "qdmtt", "iir", "utpr", "oecd", "minimum-tax", "jurisdiction", "mne", "us-exemption"]
---

# Top-up Tax / QDMTT Calculator

`POST /v1/tools/topup_tax_qdmtt_calculator`

## Request

- Base URL: `https://ainumbers.co`
- URL: `https://ainumbers.co/v1/tools/topup_tax_qdmtt_calculator`
- Auth: none declared

OECD Pillar Two top-up tax per jurisdiction. Top-up tax = (15% − ETR) × GloBE income net SBIE (Art. 5.2.1). Allocates top-up tax across QDMTT (Art. 11.3), IIR (Art. 2.1), and UTPR (Art. 2.4). ⚠ US-HQ groups exempt from IIR and UTPR per January 2026 OECD side-by-side package. Consumes T473 ETR outputs. Feeds T476 GIR Builder. Tier 1 Policy Mandate JSON + Markdown. Client-side. Works offline. Zero PII.

**Tool URL:** https://ainumbers.co/tools/474-topup-tax-qdmtt-calculator.html
**AP2/Policy Mandate export:** yes

## Request body

- object
  - `parent_hq` string, required: Parent HQ ISO-3 code — use 'US' to apply IIR/UTPR exemption
  - `fy` integer: Fiscal year (affects SBIE transitional rates)
  - `jurisdictions` object[], required
    - `jur` string, required
    - `income` number, required: GloBE income (m)
    - `taxes` number, required: Covered taxes (m)
    - `sbie` number, required: SBIE (m) from T473
    - `qdmtt_enacted` boolean: True if jurisdiction has enacted QDMTT
    - `qdmtt_rate_pct` number: QDMTT rate % (typically 15)

## Response `200`

Successful tool execution result

- object
  - `jurisdictions` unknown[]: Per-jurisdiction ETR, top-up amount, QDMTT, IIR, UTPR
    - unknown
  - `total_topup_m` number
  - `total_qdmtt_m` number
  - `total_iir_m` number
  - `total_utpr_m` number
  - `us_exempt` boolean

---

[API](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite.md) · [All operations](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/llms.txt) · [OpenAPI document](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/revisions/b462e4f5bb28?raw)