RCTab, formerly the RCV Universal Tabulator (RCVUT), is a federally tested open-source software that can tally RCV election results using cast vote records (CVRs) from most voting system vendors. In addition, RCTab can combine results from multiple different voting systems into one complete final result and can be used to audit RCV results generated by other voting systems. RCTab is the most comprehensive RCV tabulation module to be tested under the Voluntary Voting System Guidelines (VVSG) and the first open-source software to meet VVSG standards. Download the software along with instructions on how to install and use the tabulator by clicking the button at the bottom of this page.

RCTab is currently used to produce RCV official results, as a testing tool, or as an auditing tool. The State of New York certified RCTab for use in single-winner RCV elections in the State, the State of Utah certified the RCTab for use in local RCV elections, and the State of Michigan certified RCTab for use in Eastpointe, Michigan’s RCV elections. The Democratic Parties of Alaska, Kansas, and Wyoming used RCTab to produce district- and county-level results in their 2020 Presidential Preference Primaries using RCV. The Voting Methods Working Group of the NIST and EAC VVSG 2.0 development process accepted RCTab as a reference implementation to demonstrate all major variants of RCV tabulation. Benton County, Oregon, also used RCTab as a verification tool in the testing and certification process for the RCV tabulation software provided by its voting system vendor, ES&S. Successful replications of past RCV election results have been run on results in San Francisco, California, Minneapolis, Minnesota, the State of Maine, and a number of other RCV jurisdictions. RCTab successfully tallied RCV elections for the Student Government Association at the University of Houston in January 2019.

RCTab is available under an aGPLv3 License.

A visualizer, RCVis, which uses JSON files produced by RCTab, is also available.

If you are interested in using the tabulator for a ranked-choice voting election, email us at info@rcvresources.org and we can provide the support you need to use it in your jurisdiction.