1,454
▲ 27% since May 2023
Arena score of the top open-weight model in March 2026, 49 points behind the top closed-weight model (1,503)
20232026

What the chart shows

The Arena ranks chatbots by users’ blind votes between two answers, with Elo-like scores. In March 2026 the top closed-weight model scored 1,503 and the top open-weight model 1,454: a gap of 49 points, or 3.4%. The report names them as Claude Opus 4.6 and GLM-5.

The gap has swung widely. It was 174 points in May 2023, narrowed to 7 in August 2024 and 5 in February 2025, then widened again as new closed models arrived, reaching 91 in May 2025.

Key numbers

MeasureValue
Top closed-weight model, Mar 20261,503
Top open-weight model, Mar 20261,454
Gap, Mar 202649
Gap, May 2023174
Smallest gap, Feb 20255

How to read it

  • Each point is the highest score of any closed-weight or open-weight model that month on the Arena’s historical leaderboard (public, style control on), exported in March 2026.
  • Arena scores reflect user preferences in blind comparisons, not accuracy on a fixed test. Model names come from the report text; the data gives scores only.
  • Arena scores have no true zero, so the vertical axis starts at 1,100 to show the gaps; compare differences between lines, not their heights above the axis.
Source: Arena, 2026, via the AI Index Report 2026 (Stanford HAI), figure 2.1.2: Performance of top closed vs. open models on the Arena. Chart and text by AI Adoption.
Numbers checked against the published data on 20 October 2026.
Download the data (CSV) · Cite this chart