Updated: November 2, 2026

Name update: LMArena announced its change to Arena on January 28, 2026. The official current address is arena.ai; this article keeps its existing URL for continuity.

Historical image: The retained LMArena screenshot shows the earlier branding and an empty Battle prompt. Its displayed vote total is an old promotional figure, not a current count or a result measured in this audit.

Name LMArena AI (now Arena)
Overview Arena is a platform for comparing AI responses and studying human preferences. Its Battle Mode hides model identities until after voting; this reduces identity cues but does not guarantee unbiased judgments or correct answers.
Key features & limits
  • Battle versus selected models: Only votes cast while identities are hidden count toward official rankings. Side by Side lets you select models, but its votes do not enter those rankings. Direct Mode has no voting.
  • Ranking method: Arena-Rank uses Bradley–Terry modeling, including contextual extensions and confidence intervals. Calling the current method simply a real-time Elo score is misleading.
  • Open research: The Arena-Rank calculation package is open source under Apache 2.0. This does not mean every part of the hosted service or every conversation is openly released.
Use cases and applications Compare responses, explore model behavior and use preference evidence to shortlist models for further testing. A leaderboard position is not a guarantee that a model is best for your particular task. Review the relevant category, uncertainty and your own representative examples rather than relying on one rank.
Intended audience Researchers, developers, students and people evaluating AI responses. These are potential uses, not proof of suitability for every professional decision.
Free access and usage limits Checked November 2, 2026: the official credit guide describes free daily credits, with a 24-hour usage period beginning at your first prompt. A limit message shows when credits refresh. Text Arena and Code Arena Battle Mode do not consume that daily credit balance. This is not a blanket promise of unlimited access to every feature or model; follow the current in-product limits.
Privacy and research use Arena says conversations may support public research datasets and private evaluations with model providers, with shared data de-identified. Side by Side and Direct prompts are also collected for research. Avoid including sensitive information; model anonymity during a battle is not a promise of private conversations.
Topics AI comparison, human preferences, model evaluation, leaderboards, Bradley–Terry rankings.
Access Browser-based access through Arena’s official website. This audit reviewed documentation, not model outputs, account access or a native app installation.

Sources and verification

Official sources read November 2, 2026: rebrand announcement, FAQ and data-use explanation, Arena-Rank methodology and credit guide. The credit guide’s specific Battle Mode exemption is more precise than older general daily-limit guidance. No live rank, fixed model inventory or benchmark performance is asserted here.