PolicyEngine TAXSIM

The PolicyEngine TAXSIM Emulator supports all input and output variables provided by TAXSIM35. It's a drop-in replacement — install with uv tool install policyengine-taxsim and swap taxsim35 for policyengine-taxsim. Like TAXSIM35, this emulator runs entirely on your machine. Use the same CSV format you already know: provide household demographics, income, and deductions as inputs, and receive federal and state tax calculations as outputs.

Installation

Terminal

# Install uv package manager (if you don't have it)
curl -LsSf https://astral.sh/uv/install.sh | sh

# Install policyengine-taxsim
uv tool install policyengine-taxsim

If the command is not found, open Terminal and run uv tool dir --bin, then replace policyengine-taxsim with the full path shown (e.g. /Users/you/.local/bin/policyengine-taxsim).

Upgrading

To upgrade to the latest version:

Terminal

uv tool upgrade policyengine-taxsim

Version pinning

For reproducible results, pin to a specific version:

Terminal

# Install a specific version of policyengine-taxsim
uv tool install policyengine-taxsim==2.13.0

# Pin the underlying tax model for reproducible results
uv tool install policyengine-taxsim --with policyengine-us==1.555.0

Usage

Same input format, same output variables. Just swap the command.

Shell

policyengine-taxsim < input.csv > output.csv