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Head-to-head comparison

Claude Sonnet 5 vs Qwen3.8 Flash

Claude Sonnet 5 (Anthropic) and Qwen3.8 Flash (Qwen) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 3 September 2026

As of 3 September 2026, Claude Sonnet 5 holds the stronger ModelCap Index position (#15 vs #17); and Qwen3.8 Flash is 21.3× cheaper per output token ($0.47/1M vs $10.00/1M).

Which should you choose?

Choose Claude Sonnet 5 if…

  • you want the stronger overall ModelCap Index position — #15 against #17 (74.2 vs 72.1 points).
  • you want provider choice — 5 listed API providers against 1.
  • AA Humanity's Last Exam is your yardstick — 41.3% against 38.0%.

Choose Qwen3.8 Flash if…

  • API cost matters — $0.47/1M output tokens against $10.00/1M, about 21.3× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.15/1M against $2.00/1M.
  • AA Intelligence Index is your yardstick — 55.8 against 55.3.
  • AA Terminal-Bench 2.1 is your yardstick — 86.1% against 80.5%.
  • you want the more recently listed model — Qwen3.8 Flash was listed 26 August 2026, Claude Sonnet 5 30 June 2026.

Claude Sonnet 5 vs Qwen3.8 Flash: specs, pricing and context

Specification comparison of Claude Sonnet 5 and Qwen3.8 Flash
FieldClaude Sonnet 5AnthropicQwen3.8 FlashQwen
ModelCap Index position#15#17
Index score74.272.1
EvidenceMeasuredMeasured
Input price / 1M tokens$2.00$0.15
Output price / 1M tokens$10.00$0.47
Context window1M tokens1M tokens
Max output tokens128K131K
API providers listed51
Weight accessAPI onlyRestricted license
Input modalitiesText, Image, FileText, Image, Video
First listed30 June 202626 August 2026
PublisherAnthropicQwen

Evidence: 4 public benchmark observations across 4 boards · 1 public benchmark observation across 1 board. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Claude Sonnet 5 vs Qwen3.8 Flash

Public benchmark boards where Claude Sonnet 5 or Qwen3.8 Flash has a published result
BoardClaude Sonnet 5Qwen3.8 FlashLeads
Arena codingArena (LMArena)15211513–1528High—Only one result
LMArena AgentLMArena7.5%5.3%–9.7%High—Only one result
AA Intelligence IndexArtificial Analysis55.3intelligence-index55.8intelligence-indexQwen3.8 Flash
AA Terminal-Bench 2.1Artificial Analysis80.5%terminal-bench-2.186.1%terminal-bench-2.1Qwen3.8 Flash
AA Humanity's Last ExamArtificial Analysis41.3%humanitys-last-exam38.0%humanitys-last-examClaude Sonnet 5
Terminal-Bench 4.0Terminal-Bench (Laude Institute)12.4%9.4%–15.5%Claude Code · Max—Only one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Claude Sonnet 5 vs Qwen3.8 Flash: common questions

Is Claude Sonnet 5 better than Qwen3.8 Flash?

Claude Sonnet 5 ranks higher on the ModelCap Index as of 3 September 2026: #15 against #17. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it.

Is Claude Sonnet 5 cheaper than Qwen3.8 Flash?

Qwen3.8 Flash is cheaper on output tokens: $0.47/1M against $10.00/1M. Input tokens are $2.00/1M for Claude Sonnet 5 and $0.15/1M for Qwen3.8 Flash. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, Claude Sonnet 5 or Qwen3.8 Flash?

Both publish a 1M-token context window.

Which is better for coding, Claude Sonnet 5 or Qwen3.8 Flash?

AA Terminal-Bench 2.1: Claude Sonnet 5 80.5%, Qwen3.8 Flash 86.1% — Qwen3.8 Flash leads.

Are Claude Sonnet 5 and Qwen3.8 Flash open-weight models?

Claude Sonnet 5: API only. Qwen3.8 Flash: Restricted license. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run Claude Sonnet 5 and Qwen3.8 Flash?

ModelCap currently lists 5 API providers for Claude Sonnet 5 and 1 for Qwen3.8 Flash, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Claude Sonnet 5 vs Qwen3.8 Flash comparison?

Every figure comes from the sealed ModelCap dataset published 3 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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