About Chicago Budget Explorer

Open-source civic technology for budget transparency

What is this tool?

The Chicago Budget Explorer is an open-source civic tech project that makes Chicago's budget transparent, interactive, and understandable. Explore where $18.7B in tax dollars go and simulate your own budget scenarios.

Data Sources

All budget data comes from the official City of Chicago Open Data Portal via the Socrata API. We use the published budget ordinance appropriations datasets, which represent the legally approved budget passed by City Council.

  • FY2026 Data: Budget - 2026 Budget Ordinance - Appropriations (Dataset ID: 6694-f78c)
  • FY2025 Data: Budget - 2025 Budget Ordinance - Appropriations (Dataset ID: t59y-fr3k)
  • FY2024 Data: Budget - 2024 Budget Ordinance - Appropriations (Dataset ID: x394-e874)
  • FY2023 Data: Budget - 2023 Budget Ordinance - Appropriations (Dataset ID: xbjh-7zvh)

What's Included

  • All Funds: Corporate, Enterprise, Grant, and Special Revenue funds
  • Department-level Detail: See how much each city department receives
  • Revenue Breakdown: See where city revenue comes from, categorized by source type
  • Historical Trends: Compare budgets across four fiscal years with trend visualizations

What's NOT Included

  • Capital Budget: Long-term infrastructure projects (roads, buildings)
  • Actual Spending: This shows appropriations (approved budget), not actuals
  • Sister Agencies: Chicago Public Schools, Park District, CTA, and other taxing bodies
  • Revenue Projections: Revenue data shown is from budget ordinance estimates, not actual collections

Methodology

Our data pipeline:

  1. Fetches raw data from Chicago's Socrata portal
  2. Aggregates line items by department (5,000+ rows → ~50 departments)
  3. Calculates fund breakdowns and subcategories
  4. Validates that departmental totals sum correctly (within $1 tolerance for rounding)
  5. Generates JSON files consumed by this website

All code is open source and available on GitHub. You can verify our transformations and run the pipeline yourself.

Simulation Constraints

The budget simulator applies realistic constraints based on how municipal budgets work:

  • Non-adjustable Departments: Debt service and pension payments are legally mandated and cannot be reduced
  • Grant-Funded Departments: Departments with significant grant funding have tighter adjustment ranges (grants can't be easily redirected)
  • Adjustment Range: Most departments can be adjusted 50%-150% of their current budget

Features

  • City of Chicago FY2023 through FY2026 data
  • Revenue analysis and spending breakdowns
  • Historical trend visualizations across fiscal years
  • Interactive charts and budget simulator
  • Open source and free to use

How to Contribute

This is an open-source project. We welcome contributions of all kinds:

  • Code improvements and bug fixes
  • Data validation and quality checks
  • Documentation and accessibility improvements
  • New features and visualizations

Visit our GitHub repository to get started.

Credits

Built by Strong Towns Chicago, a grassroots organization advocating for financially resilient neighborhoods.

Data provided by the City of Chicago Open Data Portal.

Disclaimer

This tool is for educational and informational purposes only. While we strive for accuracy, budget data is complex and subject to change. Always verify important information with official city sources. The simulator is a simplified model and does not account for all real-world budget constraints, legal requirements, and political considerations.

Explore the Budget →