Home > Education > Affordability Calculator

Affordability Calculator

Developed by Aodhan Hemeon-McMahon, in cooperation with Housing Works Austin and ULI Austin’s Affordability Strategic Council, the Affordability Calculator is designed to help policy makers and other Affordable Housing stakeholders understand the financial viability of proposed affordable housing developments.

The tool allows users to input specific development assumptions and an Austin zip code to see if a development would be considered financially feasible for an investor. The tool does this by comparing the return generated from the user’s inputs to an internal rate of return (IRR) “hurdle”.  Users can then add subsidy assumptions and/or apply a property tax abatement to push the returns over the hurdle, if necessary.

Disclaimer: This tool is to be used for educational purposes only and is designed to allow users to compare the relative merits of one possible development over another. It should not be used as verification for a specific development’s worth or potential financial return.


Click the HERE access the Affordability Calculator Excel workbook. Once downloaded, open the Excel workbook and click to Enable Content.

  1. Change any of the yellow cells understand whether the project is financially feasible, such as:
    1. The ZIP Code that your hypothetical development would be located within to (the cell will only accept valid Austin ZIP Codes);
    2. Development specifications, such as number of units, the bedroom mix in the units, the IRR (internal rate of return) hurdle;
    3. And any further funding through property tax abatement or subsidies available to the development.
  2. You can also change other development assumptions on the right side of the spreadsheet, which are automatically populated with base assumptions using current real estate averages, but can be adjusted depending on the specifics you want to project in your hypothetical development.

Note: In order for the calculator to produce a Pass/Fail result and IRR percentage, you must select a ZIP Code and input at least 1 unit in the MFI breakdown table. Additionally, the total number of units inputted in the MFI table cannot total more than the Maximum Units in Project value (cell I23). To produce a Pass/Fail in the Policy adjustment section, you must select Yes/No for the Property Tax Abatement.

To learn more about how to use the Affordability Calculator and see the base assumptions and specific sources used to inform them, read the Affordability Calculator Description & Sources document here.


If you are having trouble downloading the file from this page, click here to download it directly from Google Drive