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Claude vs GPT

Claude Opus 5.5 vs GPT-6.1 Sol

Claude Opus 5.5 (Anthropic) and GPT-6.1 Sol (OpenAI) compared on the facts each vendor publishes. On cost, pick GPT-6.1 Sol: it lists $2 in and $10 out per 1M tokens, against $4 and $20 for Claude Opus 5.5. For very long inputs, GPT-6.1 Sol lists the larger context window: 1.05M tokens against 1M. We have not run either model: every value below is Reported, with a link to its source.

Reported Updated · Markdown · All model comparisons

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Claude Opus 5.5

Anthropic · generally available · API only · released Sep 22, 2026

$ in / 1M tokens
$4
$ out / 1M tokens
$20
Context
1M
Max output
128K

GPT-6.1 Sol

OpenAI · generally available · API only · released Sep 29, 2026

$ in / 1M tokens
$2
$ out / 1M tokens
$10
Context
1.05M
Max output
128K

How to choose

  • On cost, pick GPT-6.1 Sol: it lists $2 in and $10 out per 1M tokens, against $4 and $20 for Claude Opus 5.5.
  • For very long inputs, GPT-6.1 Sol lists the larger context window: 1.05M tokens against 1M.
  • GPT-6.1 Sol is newer, by 7 days.

Specs side by side

Each value is read from the vendor page linked beside it. “Not published” means we found no vendor figure, not that the feature is missing.

Claude Opus 5.5 vs GPT-6.1 Sol: specs with sources
SpecClaude Opus 5.5GPT-6.1 Sol
Price (as listed)$4 in / $20 out per 1M tokenssource$2 in / $10 out per 1M tokenssource
Context window1,000,000 tokens (1M)source1,050,000 tokens (1.05M)source
Max output128,000 tokenssource128,000 tokenssource
Inputtext, imagesourcetext, imagesource
Outputtextsourcetextsource
LicenceProprietary (API)sourceProprietary (API)source
ReleasedSep 22, 2026sourceSep 29, 2026source
Statusgenerally availablegenerally available
API idclaude-opus-5-5sourcegpt-6.1-solsource

Benchmark snapshots

From the boards named below, not our tests. Boards use different tasks and settings, so compare within a row, never across rows.

Benchmark snapshots for Claude Opus 5.5 vs GPT-6.1 Sol
BoardClaude Opus 5.5GPT-6.1 SolType, date
LMArena WebDev leaderboard (Elo-style score)18071749Independent, Oct 22, 2026
Terminal-Bench 4.0 official leaderboard64.8%58.2%Independent, Oct 26, 2026
SWE-bench Pro (Public), as reported by the vendors89.9%not listedVendor-reported, Oct 26, 2026
Moonshot AI: Kimi K3.1 Pro launch post (Terminal-Bench 4.0)66.4%not listedVendor-reported, Oct 23, 2026

More context: best LLM for coding.

FAQ

Which is cheaper, Claude Opus 5.5 or GPT-6.1 Sol?

Claude Opus 5.5: $4 in / $20 out per 1M tokens. GPT-6.1 Sol: $2 in / $10 out per 1M tokens. Both prices are the vendors' own listed prices on the date each model was last verified.

Which has the bigger context window?

GPT-6.1 Sol, with 1,050,000 tokens against 1,000,000.

Which is better for coding?

We have not tested either. Sourced snapshots: LMArena WebDev leaderboard (Elo-style score) (independent, Oct 22, 2026): Claude Opus 5.5 (Max) 1807, GPT-6.1 Sol (Max) 1749; Terminal-Bench 4.0 official leaderboard (independent, Oct 26, 2026): Claude Opus 5.5 (Claude Code, max) 64.8%, GPT-6.1 Sol (Codex, max) 58.2%; SWE-bench Pro (Public), as reported by the vendors (vendor-reported, Oct 26, 2026): Claude Opus 5.5 (max) 89.9%; Moonshot AI: Kimi K3.1 Pro launch post (Terminal-Bench 4.0) (vendor-reported, Oct 23, 2026): Claude Opus 5.5 66.4%. Scores from different boards are not comparable with each other.

Are Claude Opus 5.5 and GPT-6.1 Sol open source?

Claude Opus 5.5: Proprietary (API), no downloadable weights. GPT-6.1 Sol: Proprietary (API), no downloadable weights.

Did you test Claude Opus 5.5 and GPT-6.1 Sol?

No. This page is Reported: every fact is read from the vendor page linked beside it, and benchmark numbers come from the named boards.

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