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HEAD TO HEAD · UPDATED NOV 6, 2026
Claude Opus 5.5 vs GPT-6.1 Sol
Anthropic against OpenAI, 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.
| Claude Opus 5.5 | GPT-6.1 Sol | |
|---|---|---|
| Arena Elo | 1509 source ↗ | 1481 source ↗ |
| GPQA Diamond | 90.6% source ↗ | not published |
| $ per 1M in / out | $4 / $20 source ↗ | $2 / $10 source ↗ |
| Blended $ per 1M (3:1) | $8.00 source ↗ | $4.00 source ↗ |
| Context window | 1M source ↗ | 1.05M source ↗ |
| Output speed | 110 tok/s source ↗ | not published |
| Released | Sep 22, 2026 source ↗ | Sep 29, 2026 source ↗ |
| Open weights | No source ↗ | No source ↗ |
| Reasoning effort tiers | low · medium · high · xhigh · max (default: medium) | low · medium · high · xhigh · max (default: medium) |
| API effort control | output_config={"effort": "low" | "medium" | "high" | "xhigh" | "max"} source ↗ | reasoning={"effort": "low" | "medium" | "high" | "xhigh" | "max"} source ↗ |
| Additional benchmarks | Arena WebDev: 1810 (#1) source ↗ SWE-bench Pro: 89.9% source ↗ Terminal-Bench 4.0: 66.4% (xhigh) source ↗ GDPval-AA v2.1: 1846 source ↗ CursorBench 4.0: 57.8% at max effort, 52.5% at default source ↗ AA Intelligence Index v5.0.1: 59 source ↗ | AA Intelligence Index v5.0.1: 55 (Max) source ↗ |
| Best for (workload) | Anthropic suggests starting with Opus 5.5 for most workloads. #1 on Arena WebDev (1810); 66.4% on Terminal-Bench 4.0 at xhigh effort (Anthropic). source ↗ | OpenAI's near-Astra model at one-fifth of Astra's token price, with a 1.05M-token context window. 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?
For high-volume work where cost matters most, GPT-6.1 Sol is about 2.0 times cheaper per token. For overall answer quality as rated by people in blind tests, Claude Opus 5.5 leads clearly (1509 vs 1481 Arena Elo). On release timing, Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP), and OpenAI is at day 11 of a typical ~23-day gap (ADOPT NOW · FRESH RELEASE).
Key differences from the sourced numbers
- GPT-6.1 Sol is the cheaper option: $4.00 vs $8.00 per 1M tokens at a 3:1 input-to-output mix (about 2.0 times less).
- Claude Opus 5.5 scores 28 Elo points higher (1509 vs 1481) on the Arena text leaderboard, where people vote on blind side-by-side answers.
- Claude Opus 5.5 pricing note: Same rate across the full 1M context window.
- GPT-6.1 Sol pricing note: Prompts up to 272K tokens; $4 / $15 above 272K. OpenAI describes Sol as near-Astra at lower cost.
Frequently asked questions
Is Claude Opus 5.5 or GPT-6.1 Sol better?
GPT-6.1 Sol is the cheaper option: $4.00 vs $8.00 per 1M tokens at a 3:1 input-to-output mix (about 2.0 times less). Claude Opus 5.5 scores 28 Elo points higher (1509 vs 1481) on the Arena text leaderboard, where people vote on blind side-by-side answers. Claude Opus 5.5 pricing note: Same rate across the full 1M context window. GPT-6.1 Sol pricing note: Prompts up to 272K tokens; $4 / $15 above 272K. OpenAI describes Sol as near-Astra at lower cost.
Which one should I use: Claude Opus 5.5 or GPT-6.1 Sol?
For high-volume work where cost matters most, GPT-6.1 Sol is about 2.0 times cheaper per token. For overall answer quality as rated by people in blind tests, Claude Opus 5.5 leads clearly (1509 vs 1481 Arena Elo). On release timing, Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP), and OpenAI is at day 11 of a typical ~23-day gap (ADOPT NOW · FRESH RELEASE).
How much does Claude Opus 5.5 cost compared with GPT-6.1 Sol?
Claude Opus 5.5 lists at $4 / $20 per 1M input/output tokens ($8.00/1M blended at 3:1). GPT-6.1 Sol 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].