RCTab, formally the RCV Universal Tabulator (RCVUT), is federally tested open-source software that can tally RCV election results using cast vote records 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 [CH1] 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 following the link 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 Utah has 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 the RCTab as a reference implementation to demonstrate all relevant 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. Successful replications of past RCV election results have been run on results in Minneapolis, Minnesota and the State of Maine. RCTab successfully tallied RCV elections for the Student Government Association at the University of Houston in January 2019. 

RCTab has been certified by Pro V&V, Inc., an EAC-accredited voting systems test lab (VSTL), and is available under an aGPLv3 License.

A visualizer, 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.