# GPT-6.1 Sol costs 85% less per Agent Arena task than Claude Opus 5.5

> Original title: Lower cost per task doesn’t always come from lower token prices.

- Source: Arena
- Published: 2026-10-29T16:38:10.000Z
- Bad Influence: https://badinfluence.news/items/t39hc6dv856dzl5u27d5lxc7n
- Original: https://x.com/arena/status/2115845658100060527

## Summary

Arena reports that OpenAI's GPT-6.1 Sol (Max) costs $1.91 per task on Agent Arena, 85% less than Anthropic's Claude Opus 5.5 (Max) at $12.51. Against OpenAI's GPT-6 Astra (Max) at $14.93, Arena says Sol's savings come mainly from lower token prices. Against Opus, the savings come mainly from using fewer tokens per task.

## Post

Lower cost per task doesn’t always come from lower token prices.

On Agent Arena, GPT-6.1 Sol (Max) by @OpenAI costs $1.91 per task:
- 85% less than #1 Claude Opus 5.5 (Max) by @AnthropicAI at $12.51
- 87% less than #3 GPT-6 Astra (Max) by @OpenAI, at $14.93

But these savings come from different places.

Against Astra, Sol’s cost advantage comes primarily from lower token prices. Against Opus, it comes primarily from using fewer tokens per task.

How do we derive this?

Agent Arena tracks real costs of users’ tasks. Cost per task is the tokens a model uses times the price of each token, across input, output and cache-read tokens. By comparing pricing and token counts, we can identify what drives the cost reductions.

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