Skip to main content
AI Choice Engine

Model comparison

Claude Opus 5.5 vs GPT-6.1 Sol

Anthropic against OpenAI, compared on context, price, and attributed benchmark results.

Recorded profile verification October 1, 2026Individual provider fields may changeEvidence confidence: Medium — see receipts below

Anthropic

Claude Opus 5.5

Frontier

vs

OpenAI

GPT-6.1 Sol

Balanced

AI model capability comparison
SpecificationClaude Opus 5.5GPT-6.1 Sol
ProviderAnthropicOpenAI
TierFrontierBalanced
Context window1MWinner: 1.05M
Max output128K128K
Input / 1M tokens$4Winner: $2
Output / 1M tokens$20Winner: $10
WeightsClosedClosed
ParametersNot verifiedUnverifiedNot verifiedUnverified
Reasoning levelslow, medium, high, xhigh, maxlow, medium, high, xhigh, max
Modalitiestext, imagetext, image
API model idclaude-opus-5-5gpt-6.1-sol
ReleasedSeptember 22, 2026September 29, 2026
Artificial Analysis Intelligence Index [max] · source date Claude Opus 5.5: 2026-10-0158Not verifiedUnverified
Artificial Analysis Intelligence Index [max] · source date GPT-6.1 Sol: 2026-10-01Not verifiedUnverified52
Humanity's Last Exam [max] · source date Claude Opus 5.5: 2026-09-2661.4Not verifiedUnverified
Terminal-Bench 4.0 [max] · source date Claude Opus 5.5: 2026-09-2659.6Not verifiedUnverified
Terminal-Bench 4.0 [xhigh] · source date Claude Opus 5.5: 2026-09-2266.4Not verifiedUnverified

Dates beside benchmark scores refer to the linked source’s publication or capture date unless that source explicitly states when it measured the result. A shared URL alone does not establish comparable runs; unverified setups are marked. Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

  • Source date2026-10-01
    Artificial Analysis (GPT-6.1 Sol (max))

    Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.

    Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check the cited source and its date.

  • Source date2026-10-01
    Artificial Analysis (Claude Opus 5.5 (max with fallback))

    Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.

    Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check the cited source and its date.

  • Source date2026-09-26
    Artificial Analysis Terminal-Bench 4.0 (independent AA run, part of Intelligence Index v4.3.2)

    Agentic terminal work: long multi-step tasks executed in a sandboxed shell environment.

    Comparable with caveatDo not directly compare scores across Terminal-Bench versions: 4.0 revises and prunes the 3.0 task set and changes environment resources, requiring fresh trials. Within 4.0, harness, time limit, tools, sampling and resource settings must match; maintainer-agent and Artificial Analysis runs are not interchangeable.

  • Source date2026-09-26
    Artificial Analysis Humanity's Last Exam (independent, 2,158 text-only questions)

    Frontier-knowledge ceiling: extremely hard multi-domain questions written to be near-impossible without deep expertise.

    Comparable with caveatSubset/tool configurations (text-only vs with-tools) differ between vendors and materially change scores; must match configuration to compare.

  • Source date2026-09-22
    Anthropic — Claude Opus 5.5 announcement (vendor-reported, xhigh; distinct effort/harness conditions from AA's independent 59.6)

    Agentic terminal work: long multi-step tasks executed in a sandboxed shell environment.

    Comparable with caveatDo not directly compare scores across Terminal-Bench versions: 4.0 revises and prunes the 3.0 task set and changes environment resources, requiring fresh trials. Within 4.0, harness, time limit, tools, sampling and resource settings must match; maintainer-agent and Artificial Analysis runs are not interchangeable.

Pricing tiers

Claude Opus 5.5: Standard $4/$20 per MTok with no long-context surcharge. Cache reads $0.20; 5-minute writes $5 and 1-hour writes $8. Batch $2/$10. Fast research preview $8/$40 on the first-party Claude API only, not Batch. US-only inference adds 10% to all token categories where supported. Batch supports 300K output with output-300k-2026-03-24; standard output stays 128K. Knowledge cutoff Jun 2026; retirement not sooner than September 22, 2027.

GPT-6.1 Sol: Standard $2/$10 per million tokens up to 272K input; cached input $0.10 and cache writes $2.50. Above 272K, the full request costs $4/$15 ($0.20 cached, $5 cache writes). Batch/Flex are half Standard; Fast is twice Standard. Regional/FedRAMP processing adds 10% where eligible; Fast is unavailable with EU data residency. No none/minimal reasoning. Use Responses for tools; Chat Completions has no tool calling.

FrontierRecord checked October 1, 2026

Claude Opus 5.5

Claude Opus 5.5 is Anthropic's recommended default for agentic coding and knowledge work. Anthropic reports performance near Fable 5.1 on most work and about 40% lower running cost than Opus 5 under its evaluation conditions. Artificial Analysis recorded an Intelligence Index v4.3.2 score of 58 at max effort with fallback in the October 1 capture.

Best for

  • Complex agentic coding
  • Enterprise knowledge work
  • Default frontier model

Watch out

Adaptive thinking cannot be disabled; forced tool use errors. Thinking blocks are tied to model/conversation, and computer_20251124 is rejected on Claude API/Google Cloud. Progress between tool calls can be hidden in empty thinking blocks unless display returns it. Effort defaults to medium; higher effort can increase token use.

BalancedRecord checked October 1, 2026

GPT-6.1 Sol

OpenAI’s newer Sol model for coding, computer use and professional work, with the same base token price as GPT-6 Sol and lower cached-input pricing.

Best for

  • Agentic coding
  • Computer use
  • Professional work

Watch out

Compare quality on your own tasks. Reasoning starts at low; none and minimal are unsupported. Long prompts above 272K increase the rate for the whole request.

When the cheaper one wins

GPT-6.1 Sol is cheaper on output at $10 per million tokens against $20 for Claude Opus 5.5 — about 2.0×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. This compares standard short-context token rates, not total cost per accepted task. Include input, cache, context tiers, schedules, retries and review in your pilot.

Run the model picker

Evidence confidence: Medium

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 4/5 core specs verified on both sides — Not published for at least one side: parameter count.
  • No directly aligned benchmark setup — No benchmark has matching cited sources, source dates, units, effort and recorded run details on both models.
  • Verified within the last 90 days — Older of the two catalog checks was 25 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? Claude Opus 5.5 · GPT-6.1 Sol

Common questions

Claude Opus 5.5 vs GPT-6.1 Sol

Answered from the verified figures on this page rather than general guidance.

Is Claude Opus 5.5 or GPT-6.1 Sol cheaper for input?
GPT-6.1 Sol is cheaper at $2 per million input tokens, against $4 for Claude Opus 5.5 — roughly 2.0× the price. Estimate both input and output token volume for your workload. These are base rates; Claude Opus 5.5: Standard $4/$20 per MTok with no long-context surcharge. Cache reads $0.20; 5-minute writes $5 and 1-hour writes $8. Batch $2/$10. Fast research preview $8/$40 on the first-party Claude API only, not Batch. US-only inference adds 10% to all token categories where supported. Batch supports 300K output with output-300k-2026-03-24; standard output stays 128K. Knowledge cutoff Jun 2026; retirement not sooner than September 22, 2027. GPT-6.1 Sol: Standard $2/$10 per million tokens up to 272K input; cached input $0.10 and cache writes $2.50. Above 272K, the full request costs $4/$15 ($0.20 cached, $5 cache writes). Batch/Flex are half Standard; Fast is twice Standard. Regional/FedRAMP processing adds 10% where eligible; Fast is unavailable with EU data residency. No none/minimal reasoning. Use Responses for tools; Chat Completions has no tool calling.
Is Claude Opus 5.5 or GPT-6.1 Sol cheaper for output?
GPT-6.1 Sol is cheaper at $10 per million output tokens, against $20 for Claude Opus 5.5 — roughly 2.0× the price. Estimate both input and output token volume for your workload. These are base rates; Claude Opus 5.5: Standard $4/$20 per MTok with no long-context surcharge. Cache reads $0.20; 5-minute writes $5 and 1-hour writes $8. Batch $2/$10. Fast research preview $8/$40 on the first-party Claude API only, not Batch. US-only inference adds 10% to all token categories where supported. Batch supports 300K output with output-300k-2026-03-24; standard output stays 128K. Knowledge cutoff Jun 2026; retirement not sooner than September 22, 2027. GPT-6.1 Sol: Standard $2/$10 per million tokens up to 272K input; cached input $0.10 and cache writes $2.50. Above 272K, the full request costs $4/$15 ($0.20 cached, $5 cache writes). Batch/Flex are half Standard; Fast is twice Standard. Regional/FedRAMP processing adds 10% where eligible; Fast is unavailable with EU data residency. No none/minimal reasoning. Use Responses for tools; Chat Completions has no tool calling.
Which has the larger context window, Claude Opus 5.5 or GPT-6.1 Sol?
GPT-6.1 Sol accepts 1.05M tokens against 1M for Claude Opus 5.5. This only matters if you routinely send very long documents or large codebases.
Do Claude Opus 5.5 and GPT-6.1 Sol support the same reasoning levels?
Both expose these named effort settings: "low", "medium", "high", "xhigh", "max". The same labels do not guarantee equal compute budgets or behavior across providers. Compare quality, latency and cost on your own tasks.
Should I use Claude Opus 5.5 or GPT-6.1 Sol?
We classify Claude Opus 5.5 in the frontier tier and GPT-6.1 Sol in the balanced tier. Test whether either meets your accuracy, tool-use and latency requirements before choosing on price.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: GPT-6.1 Sol costs $2 per 1M tokens versus $4 for Claude Opus 5.5 — a 2x difference at the headline tier.
  • Context: GPT-6.1 Sol takes 1.05M against 1M for Claude Opus 5.5 — only decisive if your prompts approach the smaller window.
  • Positioning: Claude Opus 5.5 sits in the frontier tier, GPT-6.1 Sol in the balanced tier. Compare accuracy, reliability, latency, and cost on representative tasks before choosing.
Run the model pickerEstimate stack costAll model comparisons

Choosing a harness rather than a model — Cursor, Copilot, Claude Code, Windsurf, or Lovable? Compare agentic harnesses · Latest releases.