KalkulatorPajak

KalkulatorPajak is an R package for computing income tax in accordance with the Indonesian Income Tax Law (Undang-Undang Pajak Penghasilan).
The package provides reproducible, transparent, and law-compliant tax computation methods for both individual and corporate taxpayers.

🧭 Objective

The package aims to deliver a reliable computational framework for quantitative and educational analysis of Indonesian tax obligations.
All implemented functions adhere to key legal provisions, including:

• Article 2(3a) — Definition of Individual Tax Resident
• Article 17(1a) — Progressive Tax Rates for Individuals
• Article 17(1b) — Corporate Income Tax Rates
• Article 7(1) — Personal Allowance (PTKP) Deductions

This project supports both academic research and practical tax computation workflows in R.

⚙️ Current Features

• Functions for individual and corporate income tax calculation:
  • pph17p1a() — Individual income tax (Article 17 paragraph 1a)
  • pph17p1b() — Corporate income tax (Article 17 paragraph 1b)
• PTKP (Personal Tax-Free Threshold) computation: pph7p1()
• Super simple individual tax return form (SPT 1770-SS): sptopss()
• Foundational modules for tax validation and summary generation.

🧩 Example Usage

library(KalkulatorPajak)

# Calculate Individual Income Tax (Article 17 paragraph 1a)
pph17p1a(75000000)

# Calculate Corporate Income Tax (Article 17 paragraph 1b)
pph17p1b(500000000)

# Retrieve PTKP (Personal Allowance) by taxpayer status
pph7p1("K/1")

# Compute basic 1770-SS return
sptopss(income = 80000000, status = "TK/0")

🧠 Methodological Notes

• Fully implemented in R, designed for reproducible tax computation and data-driven policy simulation.
• Legal logic is derived from the Indonesian Income Tax Law (UU PPh) and its implementing regulations.
• All computational steps are explicit and traceable for audit and research purposes.
• Modular architecture enables integration into larger analytical or reporting pipelines.

To Do

• Core Stabilization Strengthening core computation and documentation consistency. (ex: refactor code, unit test, roxygen2, datasets, validation and summarization)
• Extended Coverage Expanding coverage for individuals and simplified entities. (ex: final tax, withholding tax, export csv)
• Corporate & Integration Extending to corporate taxpayers and consolidated tax analysis.
• Data Integration Enhancing interoperability and standard data exchange. (ex: XLSX, XBRL)

📚 Citation

If you use KalkulatorPajak in your research, please cite it as:

Tejaningrat, Yudha H. (2017). KalkulatorPajak: Tax Computation Based on Indonesian Income Tax Law (UU PPh). R package version 0.x. https://github.com/yht/KalkulatorPajak