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HEAD TO HEAD · UPDATED NOV 6, 2026
GPT-6.1 Sol vs Claude Sonnet 5.5
OpenAI against Anthropic, on sourced numbers only. Green marks the higher (or cheaper) value on each row; the text below only calls a lead when the gap is bigger than measurement noise.
| GPT-6.1 Sol | Claude Sonnet 5.5 | |
|---|---|---|
| Arena Elo | 1481 source ↗ | 1477 source ↗ |
| GPQA Diamond | not published | 95.6% source ↗ |
| $ per 1M in / out | $2 / $10 source ↗ | $2 / $10 source ↗ |
| Blended $ per 1M (3:1) | $4.00 source ↗ | $4.00 source ↗ |
| Context window | 1.05M source ↗ | 1M source ↗ |
| Output speed | not published | 155 tok/s source ↗ |
| Released | Sep 29, 2026 source ↗ | Sep 28, 2026 source ↗ |
| Open weights | No source ↗ | No source ↗ |
| Reasoning effort tiers | low · medium · high · xhigh · max (default: medium) | low · medium · high · xhigh · max (default: high) |
| API effort control | reasoning={"effort": "low" | "medium" | "high" | "xhigh" | "max"} source ↗ | output_config={"effort": "low" | "medium" | "high" | "xhigh" | "max"} source ↗ |
| Additional benchmarks | AA Intelligence Index v5.0.1: 55 (Max) source ↗ | SWE-bench Pro: 81.3% source ↗ AA Intelligence Index v5.0.1: 55 source ↗ |
| Best for (workload) | OpenAI's near-Astra model at one-fifth of Astra's token price, with a 1.05M-token context window. source ↗ | Fast (155 tok/s, Artificial Analysis) and strong on science: 95.6% GPQA Diamond at max effort (Epoch AI), above Opus 5.5's 90.6%. source ↗ |
Arena Elo from the arena.ai text leaderboard as of Oct 27, 2026 source ↗. Speed measured by Artificial Analysis and varies by provider.
Which one should I use?
On the published numbers these two are close; pick on price notes, context window or the provider you already use. On release timing, OpenAI is at day 11 of a typical ~23-day gap (ADOPT NOW · FRESH RELEASE), and Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP).
Key differences from the sourced numbers
- They cost about the same: $4.00 vs $4.00 per 1M tokens at a 3:1 mix.
- On the Arena text leaderboard they are close (1481 vs 1477): a gap under 20 points is within the leaderboard's margin of error.
- GPT-6.1 Sol pricing note: Prompts up to 272K tokens; $4 / $15 above 272K. OpenAI describes Sol as near-Astra at lower cost.
- Claude Sonnet 5.5 pricing note: Same rate across the full 1M context window.
Frequently asked questions
Is GPT-6.1 Sol or Claude Sonnet 5.5 better?
They cost about the same: $4.00 vs $4.00 per 1M tokens at a 3:1 mix. On the Arena text leaderboard they are close (1481 vs 1477): a gap under 20 points is within the leaderboard's margin of error. GPT-6.1 Sol pricing note: Prompts up to 272K tokens; $4 / $15 above 272K. OpenAI describes Sol as near-Astra at lower cost. Claude Sonnet 5.5 pricing note: Same rate across the full 1M context window.
Which one should I use: GPT-6.1 Sol or Claude Sonnet 5.5?
On the published numbers these two are close; pick on price notes, context window or the provider you already use. On release timing, OpenAI is at day 11 of a typical ~23-day gap (ADOPT NOW · FRESH RELEASE), and Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP).
How much does GPT-6.1 Sol cost compared with Claude Sonnet 5.5?
GPT-6.1 Sol lists at $2 / $10 per 1M input/output tokens ($4.00/1M blended at 3:1). Claude Sonnet 5.5 lists at $2 / $10 per 1M input/output tokens ($4.00/1M blended at 3:1).
Facts checked Nov 5, 2026 against official sources. Every number links to its source. Spotted an error? Email [email protected].