Claude Sonnet 5.5 or Qwen3.8 Max 0902: which to choose?

Two models head to head

Claude Sonnet 5.5 and Qwen3.8 Max 0902 are two frontier models, the ones you pick when quality comes first, one from Anthropic, the other from Alibaba Cloud (Qwen). Claude Sonnet 5.5 was released on September 28, 2026, Qwen3.8 Max 0902 on September 2, 2026.

All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.

What the benchmarks say

On our capability index, Claude Sonnet 5.5 scores 95.9 out of 100 and Qwen3.8 Max 0902 88.4. Claude Sonnet 5.5 leads by 7.5 points.

On the 3 benchmarks reported for both, Claude Sonnet 5.5 wins 2 times and Qwen3.8 Max 0902 0:

• GPQA Diamond (PhD-level science questions): Claude Sonnet 5.5 95.6%, Qwen3.8 Max 0902 92.3%
• OTIS Mock AIME (competition mathematics problems): Claude Sonnet 5.5 100%, Qwen3.8 Max 0902 100%
• FrontierMath (very hard research-level mathematics): Claude Sonnet 5.5 88.8%, Qwen3.8 Max 0902 65.6%

Which one costs less?

Claude Sonnet 5.5 costs $2 per million input tokens and $10 per million output tokens; Qwen3.8 Max 0902 costs $2 and $6.

For a typical agent task (read 20,000 tokens, write 2,000), expect $0.06 with Claude Sonnet 5.5 versus $0.052 with Qwen3.8 Max 0902. Qwen3.8 Max 0902 is 1.2 times cheaper, a gap that adds up quickly over 1,000 tasks: $8 difference.

Run the numbers with your own volumes in the agent cost calculator.

Under the hood

Both models have the same context window: 1,000,000 tokens, roughly 1,500 pages.

Reasoning mode: Claude Sonnet 5.5 yes, Qwen3.8 Max 0902 yes. Tool calling: Claude Sonnet 5.5 yes, Qwen3.8 Max 0902 yes. Image input: Claude Sonnet 5.5 yes, Qwen3.8 Max 0902 yes.

Neither publishes its weights: both are used through an API.

In short

Our reading of the data:

• Choose Claude Sonnet 5.5 for a higher capability index.
• Choose Qwen3.8 Max 0902 for a lower cost.

This verdict relies on public figures; it does not replace a trial on your own tasks.