Claude Sonnet 5.5 vs Qwen3.8 Flash: Specs & Benchmark Comparison
Claude Sonnet 5.5 is developed by Anthropic, while Qwen3.8 Flash comes from Alibaba. Qwen3.8 Flash was released in August 2026, and Claude Sonnet 5.5 followed a month later in September 2026. Qwen3.8 Flash has a published size of about 125 billion parameters; Anthropic has not disclosed the parameter count of Claude Sonnet 5.5.
The two models share 3 published benchmarks. Claude Sonnet 5.5 leads on 3 of them. The widest gaps are on SWE-Bench Pro, where Claude Sonnet 5.5 scores 81.3% against 62.5%; DeepSWE 1.1, where Claude Sonnet 5.5 scores 71.0% against 58.7%. Averaged across everything we track, Claude Sonnet 5.5 sits at 67.4% and Qwen3.8 Flash at 68.5%.
Qwen3.8 Flash is the cheaper API at $0.15 per million input tokens and $0.47 per million output tokens, roughly 13 times cheaper than Claude Sonnet 5.5 at $2 and $10. Both accept a context window of about 1M tokens. Claude Sonnet 5.5 accepts text and images as input, while Qwen3.8 Flash accepts text, images, and video. On tooling, only Claude Sonnet 5.5 supports function calling and only Claude Sonnet 5.5 offers structured output.
| Characteristic | Claude Sonnet 5.5 | Qwen3.8 Flash |
|---|---|---|
| Company | Anthropic | Alibaba |
| Release Date | September 28, 2026 | August 26, 2026 |
| Parameters | — | 125B |
| Multimodal | Yes | Yes |
| Context (input) | 1.0M | 1.0M |
| Context (output) | 128K | 131K |
| Input Price / 1M | $2.00 | $0.15 |
| Output Price / 1M | $10.00 | $0.47 |
| Average Score | 67.4% | 68.5% |
| Benchmarks | ||
| SWE-Bench Pro | 81.3% | 62.5% |
| DeepSWE 1.1 | 71.0% | 58.7% |
| SWE-bench Multilingual | 90.3% | 81.0% |
Visual Benchmark Comparison
Verdict
Both models show equal results — the choice depends on your specific use case.
Both models show comparable average scores: Claude Sonnet 5.5 — 0.7, Qwen3.8 Flash — 0.7.
Qwen3.8 Flash is 19.4x cheaper: input $0.15/1M vs $2.00/1M tokens.
Same context size: 1M tokens.
Claude Sonnet 5.5 is newer: released 9/28/2026 vs 8/26/2026.
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Frequently Asked Questions
Which is better for coding — Claude Sonnet 5.5 or Qwen3.8 Flash?
Which model is cheaper — Claude Sonnet 5.5 or Qwen3.8 Flash?
Which has a larger context window — Claude Sonnet 5.5 or Qwen3.8 Flash?
The Claude Sonnet 5.5 and Qwen3.8 Flash comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the Claude Sonnet 5.5 or Qwen3.8 Flash page. See also the complete list of AI model comparisons.