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Claude Sonnet 5.5 vs GPT-6.1 Sol
Of the 6 public leaderboards that rate both, Claude Sonnet 5.5 scores higher on 4 and GPT-6.1 Sol on 2. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Claude Sonnet 5.5 is at 90.3 and GPT-6.1 Sol at 88.2 (out of 100).
Scores as published by each board; table composed October 8, 2026.
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Leaderboard by leaderboard
| Board | Claude Sonnet 5.5 | GPT-6.1 Sol | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,774.3 | 1,755.4 | Claude Sonnet 5.5 |
| LiveBench global average (0-100) | 77.8 | 81.6 | GPT-6.1 Sol |
| SimpleBench AVG@5 % (private set) | 75.9 | 82.9 | GPT-6.1 Sol |
| LLM Stats LLM Stats Score · composite (0-100), their rendered top 15 | 58.3 | 53.9 | Claude Sonnet 5.5 |
| Vals AI Vals Index accuracy % · weighted finance + coding tasks | 67 | 61.2 | Claude Sonnet 5.5 |
| Artificial Analysis intelligence index · measured runs only | 56 | 51.8 | Claude Sonnet 5.5 |
Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.
For coding
On the ArtificialWatch coding index, Claude Sonnet 5.5 is at 88.2 (#3 of 35) and GPT-6.1 Sol at 82.4 (#6). Claude Sonnet 5.5 scores higher on 2 of the 3 coding boards that rate both and GPT-6.1 Sol on 1.
| Coding board | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| LMArena · Coding | 1,531.8 | 1,545.3 |
| LiveBench · Coding | 73.8 | 68.8 |
| Vals Vibe Code Bench | 92.4 | 88.9 |
Claude Sonnet 5.5 at a glance
- Developer
- Anthropic
- Status
- Live since September 28, 2026
- API price
- $2 input / $10 output per 1M tokens · Anthropic, claude-sonnet-5-5
- Context window
- 1M tokens
Live — Sep 28 · $2/$10 per MTok, the same as Sonnet 5 · cache reads $0.20 at launch, halved to $0.10 on Oct 7, writes $2.50 · in the API, the Claude apps, AWS, Google Cloud and Azure the same day · 1M ctx / 128K out · knowledge cutoff Jun 2026 · Artificial Analysis Intelligence Index 56 at max effort, #3 of 216 reasoning models (read Sep 28) · Anthropic's own table: Terminal-Bench 4.0 70.6% (Opus 5.5 66.4%), OSWorld 2.1 80.1% (Opus 5.5 81.8%) · our sweep caught claude-sonnet-5-5 at 17:54 UTC and fired at 17:55.
Claude Sonnet 5.5 ships at Sonnet 5's price, and the first independent number puts it #3 among reasoning models
2026-09-28 · Claude Sonnet 5.5 is live. Our sweep read the id claude-sonnet-5-5 at 17:54:45 UTC on September 28 and the alert went out at 17:55:45, 60 seconds later, to 314 inboxes and one phone. OpenRouter listed it nine minutes after that.
Claude Sonnet 5.5: named by Anthropic, reportedly in partner testing, priced 89% by Sep 30
2026-09-27 · Anthropic has named Claude Sonnet 5.5 but has not dated it. Everything past the name is reported, not confirmed - and the one number that moves every day says it is close.
GPT-6.1 Sol at a glance
- Developer
- OpenAI
- Status
- Live since September 29, 2026
- API price
- $2 input / $10 output per 1M tokens · OpenAI, gpt-6.1-sol
- Context window
- 1.05M tokens
Live — Sep 29, launched at DevDay · Ultrafast tier open to all API users Oct 8 at $12/$60 (six times standard, OpenAI's pricing page) · $2/$10 per 1M, cached input $0.10 (half of GPT-6 Sol's) · in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise and Edu, not yet in Chat · OpenAI says it nearly matches GPT-6 Astra on agentic coding, computer use and professional work at a fifth of Astra's price · Artificial Analysis Intelligence Index 52 at max effort, #10 of 221 reasoning models (read Sep 29) · 1.05M ctx as OpenRouter lists it, which also carries gpt-6.1-sol-pro (the same model in a pro reasoning mode) · Ultrafast (up to 8x faster in Codex) 'in the coming days' · our sweep read gpt-6.1-sol on OpenAI's public model docs at 17:23 UTC and fired at 17:24, about 20 minutes after the keynote.
GPT-6.1 Sol Ultrafast opens to every API user at $12 / $60, six times standard Sol
2026-10-08 · OpenAI's Ultrafast tier now covers GPT-6.1 Sol for every API user. OpenAI's API docs, read on October 8, say Ultrafast mode is "broadly available" for GPT-6 Astra and GPT-6.1 Sol and "available to all API users", with preview access for GPT-5.6 Sol.
GPT-6.1 Sol ships at DevDay at $2/$10, and OpenAI says it nearly matches Astra
2026-09-29 · OpenAI launched GPT-6.1 Sol at its DevDay keynote on September 29. It is available now in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise and Edu users, not yet in Chat, and in the API as gpt-6.1-sol.
Claude Sonnet 5.5 vs GPT-6.1 Sol: quick answers
Which is better, Claude Sonnet 5.5 or GPT-6.1 Sol?
It depends on what you measure. Of the 6 public leaderboards that rate both, Claude Sonnet 5.5 scores higher on 4 and GPT-6.1 Sol on 2. Claude Sonnet 5.5's widest lead is on LLM Stats; GPT-6.1 Sol's widest lead is on SimpleBench. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Claude Sonnet 5.5 is at 90.3 and GPT-6.1 Sol at 88.2 (out of 100).
Which is newer, Claude Sonnet 5.5 or GPT-6.1 Sol?
GPT-6.1 Sol. It went live on September 29, 2026, 1 day after Claude Sonnet 5.5 (September 28, 2026).
Which is cheaper, Claude Sonnet 5.5 or GPT-6.1 Sol?
They cost the same per token. On each vendor's own API, Claude Sonnet 5.5 is $2 input / $10 output per million tokens and GPT-6.1 Sol is $2 input / $10 output per million tokens. GPT-6.1 Sol's rate rises for prompts over 272K tokens. Prices as published in the models.dev catalog, as of 2026-10-08.
Which has the bigger context window, Claude Sonnet 5.5 or GPT-6.1 Sol?
GPT-6.1 Sol, at 1.05M tokens against Claude Sonnet 5.5's 1M, as each vendor lists it.
How do Claude Sonnet 5.5 and GPT-6.1 Sol compare for coding?
On the ArtificialWatch coding index, Claude Sonnet 5.5 is at 88.2 (#3 of 35) and GPT-6.1 Sol at 82.4 (#6). Claude Sonnet 5.5 scores higher on 2 of the 3 coding boards that rate both and GPT-6.1 Sol on 1.
Who makes Claude Sonnet 5.5 and GPT-6.1 Sol?
Claude Sonnet 5.5 is from Anthropic; GPT-6.1 Sol is from OpenAI.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed October 8, 2026). Boards measure different things, so raw scores are only comparable within a row.
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