---
id: policyengine-us
version: "1.808.0"
license: unclear
license_treatment: agpl
maintenance: active
---

# policyengine-us — US federal and state tax-benefit microsimulation model.

License: agpl · Maintenance: active · Downloads: 167.4K/mo

## What it is and what it does

PolicyEngine US is a microsimulation engine that encodes the rules of the US federal and state tax and benefit system, allowing you to compute tax liabilities, benefit eligibility, and household-level financial outcomes under different policy scenarios. It is built on policyengine-core and integrates with pandas, microdf-python, spm-calculator, and tables to handle data processing and tabular storage.

The package is actively maintained and positioned as the authoritative source for US tax-benefit rules and household calculations. However, the description explicitly notes that direct microsimulation via the Microsimulation() class is deprecated; the maintainers recommend using the policyengine.py bundle for population-wide modeling, which pins certified and calibration-gated datasets. Microsimulation results are estimates and should be validated against the calibration diagnostics.

Use it for:

- Compute household tax liability and benefit eligibility under current or proposed tax-benefit rules.
- Analyze distributional or budgetary impacts of policy changes on specific household types.
- Validate policy proposals by running microsimulation scenarios against calibrated US demographic and income data.
- Integrate US tax-benefit calculations into a larger policy analysis or research workflow.
- Inspect and audit the encoded rules of the federal and state tax-benefit system.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

PolicyEngine US models the US federal and state tax and benefit system for household-level microsimulation calculations, computing tax liabilities, benefit eligibility, and distributional impacts.

Yes, if you need to model US household-level tax and benefit outcomes and are comfortable with AGPL v3 licensing. The package is actively maintained, has low install friction, and is the canonical source for US tax-benefit rules. However, note that direct microsimulation is deprecated in favor of the policyengine.py bundle for population-wide analysis. Verify that your Python version (3.11–3.14) and pandas 3+ are available before installing.

## Install

pip install policyengine-us
uv add policyengine-us
poetry add policyengine-us

## Installing policyengine-us

Before you install: Low install friction with a pure-Python wheel. Actively maintained with a release on 2026-08-14. Requires Python 3.11–3.14 and pandas 3 or later; verify your environment matches before installing.

License in practice: Licensed under AGPL v3, which requires that any modifications or derivative works be shared under the same license and that source code be made available to users. This is a strong copyleft obligation suitable for open research but may constrain commercial or proprietary use.

Quickstart:

pip install policyengine-us

from policyengine_us import Microsimulation

sim = Microsimulation()
# Household-level tax and benefit calculations follow

Requires Python 3.11–3.14 and pandas 3 or later. Direct microsimulation via Microsimulation() is deprecated; the description recommends using the policyengine.py bundle for population-wide modeling instead.

Verify before relying:

- Exact calibration quality and validation metrics for microsimulation estimates beyond the reference to calibration-diagnostics.vercel.app.
- Performance characteristics (runtime, memory) for typical household-scale and population-scale simulations.
- Whether the package's tax-benefit rules are current with the latest federal and state legislation as of the fact sheet date.

## Package facts

- License: not declared (agpl)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 167.4K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

tax benefit microsimulation, US tax calculator, welfare policy modeling, household tax computation, policy impact analysis, state federal tax rules, benefit eligibility calculator, tax-policy-modeling, microsimulation, open-research

[View on SkillFed](https://skillfed.io/packages/policyengine-us) · [View on PyPI](https://pypi.org/project/policyengine-us/)