Runs in your browser
No downloads or sign-ups are required. OpenTally counts are computed entirely inside your browser, and no data ever leaves your computer.
Wide range of STV systems
OpenTally supports Gregory (inclusive and exclusive, weighted and unweighted), Meek and Wright variants of the single transferable vote.
Support for arbitrary constraints
OpenTally is the only publicly available election counting software to support arbitrary combinations of constraints, such as gender quotas and other affirmative action requirements.
Free and open source
Source code for OpenTally is publicly available under the GNU AGPLv3.
From our blog
Latest news and posts from the OpenTally blog
Parcels? Subparcels? Not just for STV hand counts!
Single transferable vote rules designed for hand-counting often contain references to ‘parcels’ (or ‘bundles’ or ‘batches’), ‘further parcels’ and sometimes even ‘subparcels’.
For example, consider the 4th stage of the ERS97 model election. 107 of Glazier's and Wright's ballot papers are aggregated according to…
Implementing a BLT parser by hand in Rust (vs pest and combine)
Asyncify with vanilla JS/
WebAssembly (wasm-bindgen compatible)
WebAssembly is a technology for executing compiled programs in the web browser at near-native speeds. However, it has a number of current limitations, including that it does not support coroutines/
In OpenTally, WebAssembly is used to run code for counting an election. This…