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Comparison · 2 models · Updated Oct 4, 2026

GPT-5.5 vs Claude Opus 4.6

Too close to call on our weighted score (GPT-5.5 63, Claude Opus 4.6 61). The right pick depends on what you value most.

  1. OpenAI

    GPT-5.5

    Released Apr 23, 2026

    63/100
    • ECI159.2
    • Price$5.00 / $30.00
    • Context1.05M
    Full specs Remove GPT-5.5

  2. Anthropic

    Claude Opus 4.6

    Released Feb 5, 2026

    61/100
    • ECI155.3
    • Price$5.00 / $25.00
    • Context1M
    Full specs Remove Claude Opus 4.6

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Too close to call

It is close. Our weighted score puts them within 2 points (GPT-5.5 63/100, Claude Opus 4.6 61/100), so choose by what matters most for your work: GPT-5.5 for raw capability and Claude Opus 4.6 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT-5.5Capabilities Index (ECI): GPT-5.5 159.2 · Claude Opus 4.6 155.3
  • Lowest priceClaude Opus 4.6Claude Opus 4.6 $10.00 · GPT-5.5 $11.25 per 1M tokens (3:1 blend)
  • Longest contextGPT-5.5GPT-5.5 1,050,000 · Claude Opus 4.6 1,000,000 tokens
  • Widest inputsSame inputsGPT-5.5: Text, Images, PDFs · Claude Opus 4.6: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.5Claude Opus 4.6
CapabilityCapabilities Index (ECI)50%9085
Price25%02
Inputs & features15%8080
Context window10%6160
Overall100%63/10061/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.5 vs Claude Opus 4.6 specifications side by side
SpecificationGPT-5.5OpenAIClaude Opus 4.6Anthropic
Capability
Capabilities Index (ECI)159.2 (best)155.3
ECI rank#10 of 148 (best)#27 of 148
GPQA DiamondGraduate-level science questions94.0% (best)90.5%
FrontierMath Tiers 1–3Research-level mathematics85.3% (best)66.0%
OTIS Mock AIME 2024–2025Competition mathematics100% (best)94.4%
SWE-bench VerifiedFixing real GitHub issues80.6% (best)78.7%
SimpleQA VerifiedShort factual questions63.0% (best)47.0%
Price per million tokens
Input$5.00$5.00
Output$30.00$25.00 (best)
Cached input$0.50$0.50
Blended (3:1)$11.25$10.00 (best)
Long-context rateOver 272K: $10.00 / $45.00Same rate
Price sourceOfficial OpenAI APIOfficial Anthropic API
Limits
Context window1,050,000 tokens (best)1,000,000 tokens
Max output128,000 tokens128,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · high · xhighYeslow · medium · high · max
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5.5claude-opus-4-6
API providers42 (best)33
ReleasedApr 23, 2026Feb 5, 2026
Knowledge cutoffDec 1, 2025May 31, 2025
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.5$110.00
  • Claude Opus 4.6$100.00
04 — Questions

Which should you choose?

Which is better: GPT-5.5 or Claude Opus 4.6?

It is close. Our weighted score puts them within 2 points (GPT-5.5 63/100, Claude Opus 4.6 61/100), so choose by what matters most for your work: GPT-5.5 for raw capability and Claude Opus 4.6 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.5 or Claude Opus 4.6?

Claude Opus 4.6 is cheaper at $5.00 input / $25.00 output per million tokens (official Anthropic API price). GPT-5.5 costs $5.00 input / $30.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $10.00 per million tokens for Claude Opus 4.6 versus $11.25 for GPT-5.5 (1.1× as much).

Which scores higher on benchmarks?

GPT-5.5 scores higher on the Capabilities Index (ECI): GPT-5.5 159.2 (#10 of 148) and Claude Opus 4.6 155.3 (#27 of 148). The confidence ranges of the top two overlap (156.9–162.4 vs 153.4–157.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT-5.5 94.0%, Claude Opus 4.6 90.5%; FrontierMath Tiers 1–3 — GPT-5.5 85.3%, Claude Opus 4.6 66.0%; OTIS Mock AIME 2024–2025 — GPT-5.5 100%, Claude Opus 4.6 94.4%; SWE-bench Verified — GPT-5.5 80.6%, Claude Opus 4.6 78.7%; SimpleQA Verified — GPT-5.5 63.0%, Claude Opus 4.6 47.0%.

Which is better for coding?

GPT-5.5 resolves more real GitHub issues on SWE-bench Verified: GPT-5.5 80.6% and Claude Opus 4.6 78.7%. Both support tool calling for agent workflows.

Which has the bigger context window?

GPT-5.5 has the largest context window at 1,050,000 tokens, against 1,000,000 for Claude Opus 4.6. Maximum output per response: GPT-5.5 up to 128,000, Claude Opus 4.6 up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT-5.5 accepts text, images and PDFs; Claude Opus 4.6 accepts text, images and PDFs. They handle the same number of input types.

Are any of these open source?

No. GPT-5.5 and Claude Opus 4.6 are proprietary and only available through APIs and apps.

Which is newer?

GPT-5.5 is the newest, released Apr 23, 2026. Claude Opus 4.6 came out Feb 5, 2026. Knowledge cutoff: GPT-5.5 Dec 1, 2025, Claude Opus 4.6 May 31, 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.

05 — Keep comparing

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