ZMIME
Comparison · 3 models · Updated Oct 4, 2026

GPT-5.1 vs Claude Opus 4.5 vs Claude Opus 5

Claude Opus 5 comes out ahead, 66 to 60 and 55 on our weighted score, though GPT-5.1 is 2.9× cheaper per token.

  1. OpenAI

    GPT-5.1

    Released Nov 13, 2025

    60/100
    • ECI149.7
    • Price$1.25 / $10.00
    • Context400K
    Full specs Remove GPT-5.1

  2. Anthropic

    Claude Opus 4.5

    Released Nov 24, 2025

    55/100
    • ECI150.1
    • Price$5.00 / $25.00
    • Context200K
    Full specs Remove Claude Opus 4.5
  3. Our pick

    Anthropic

    Claude Opus 5

    Released Jul 24, 2026

    66/100
    • ECI162.9
    • Price$5.00 / $25.00
    • Context1M
    Full specs Remove Claude Opus 5
01 — Verdict

Claude Opus 5 is our pick

Claude Opus 5 is the better all-round choice, scoring 66/100 against GPT-5.1 (60) and Claude Opus 4.5 (55). It leads on capability and context window. GPT-5.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityClaude Opus 5Capabilities Index (ECI): Claude Opus 5 162.9 · Claude Opus 4.5 150.1 · GPT-5.1 149.7
  • Lowest priceGPT-5.1GPT-5.1 $3.44 · Claude Opus 4.5 $10.00 · Claude Opus 5 $10.00 per 1M tokens (3:1 blend)
  • Longest contextClaude Opus 5Claude Opus 5 1,000,000 · GPT-5.1 400,000 · Claude Opus 4.5 200,000 tokens
  • Widest inputsClaude Opus 4.5 and Claude Opus 5GPT-5.1: Text, Images · Claude Opus 4.5: Text, Images, PDFs · Claude Opus 5: Text, Images, PDFs
  • Self-hostingNo open weightsAll three are available only through APIs
How the score is built
MeasureWeightGPT-5.1Claude Opus 4.5Claude Opus 5
CapabilityCapabilities Index (ECI)50%787894
Price25%2422
Inputs & features15%708080
Context window10%443260
Overall100%60/10055/10066/100
02 — Side by side

Every spec in one table

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

GPT-5.1 vs Claude Opus 4.5 vs Claude Opus 5 specifications side by side
SpecificationGPT-5.1OpenAIClaude Opus 4.5AnthropicClaude Opus 5Anthropic
Capability
Capabilities Index (ECI)149.7150.1162.9 (best)
ECI rank#52 of 148#48 of 148#5 of 148 (best)
GPQA DiamondGraduate-level science questions87.6%86.1%93.9% (best)
FrontierMath Tiers 1–3Research-level mathematics—34.4%85.6% (best)
OTIS Mock AIME 2024–2025Competition mathematics88.6%86.1%98.9% (best)
SWE-bench VerifiedFixing real GitHub issues68.0%76.7% (best)—
SimpleQA VerifiedShort factual questions48.0%45.7%59.9% (best)
Price per million tokens
Input$1.25 (best)$5.00$5.00
Output$10.00 (best)$25.00$25.00
Cached input$0.125 (best)$0.50$0.50
Blended (3:1)$3.44 (best)$10.00$10.00
Long-context rateSame rateSame rateSame rate
Price sourceOfficial OpenAI APIOfficial Anthropic APIOfficial Anthropic API
Limits
Context window400,000 tokens200,000 tokens1,000,000 tokens (best)
Max output128,000 tokens (best)64,000 tokens128,000 tokens (best)
Inputs and features
TextYesYesYes
ImagesYesYesYes
PDFsNoYesYes
AudioNoNoNo
VideoNoNoNo
ReasoningYeslow · medium · highYeslow · medium · highYeslow · medium · high · xhigh · max
Tool callingYesYesYes
Structured outputYesYesYes
Availability
WeightsProprietaryProprietaryProprietary
API model IDgpt-5.1claude-opus-4-5claude-opus-5
API providers212835 (best)
ReleasedNov 13, 2025Nov 24, 2025Jul 24, 2026
Knowledge cutoffSep 30, 2024May 2025May 2026
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-5.1$32.50
  • Claude Opus 4.5$100.00
  • Claude Opus 5$100.00
04 — Questions

Which should you choose?

Which is better: GPT-5.1, Claude Opus 4.5 or Claude Opus 5?

Claude Opus 5 is the better all-round choice, scoring 66/100 against GPT-5.1 (60) and Claude Opus 4.5 (55). It leads on capability and context window. GPT-5.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.1, Claude Opus 4.5 or Claude Opus 5?

GPT-5.1 is cheaper at $1.25 input / $10.00 output per million tokens (official OpenAI API price). Claude Opus 4.5 costs $5.00 input / $25.00 output per million tokens (official Anthropic API price); Claude Opus 5 costs $5.00 input / $25.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $3.44 per million tokens for GPT-5.1 versus $10.00 for Claude Opus 4.5 (2.9× as much) and $10.00 for Claude Opus 5 (2.9× as much).

Which scores higher on benchmarks?

Claude Opus 5 scores higher on the Capabilities Index (ECI): Claude Opus 5 162.9 (#5 of 148), Claude Opus 4.5 150.1 (#48 of 148) and GPT-5.1 149.7 (#52 of 148). Their confidence ranges do not overlap (160.2–166.7 vs 147.9–153.0), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Opus 5 93.9%, GPT-5.1 87.6%, Claude Opus 4.5 86.1%; OTIS Mock AIME 2024–2025 — Claude Opus 5 98.9%, GPT-5.1 88.6%, Claude Opus 4.5 86.1%; SimpleQA Verified — Claude Opus 5 59.9%, GPT-5.1 48.0%, Claude Opus 4.5 45.7%.

Which is better for coding?

There are no published SWE-bench Verified results for Claude Opus 5 yet, so there is no like-for-like coding score. On overall capability, Claude Opus 5 leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

Which has the bigger context window?

Claude Opus 5 has the largest context window at 1,000,000 tokens, against 400,000 for GPT-5.1 and 200,000 for Claude Opus 4.5. Maximum output per response: GPT-5.1 up to 128,000, Claude Opus 4.5 up to 64,000, Claude Opus 5 up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT-5.1 accepts text and images; Claude Opus 4.5 accepts text, images and PDFs; Claude Opus 5 accepts text, images and PDFs. Claude Opus 4.5 handles the widest range of inputs.

Are any of these open source?

No. GPT-5.1, Claude Opus 4.5 and Claude Opus 5 are proprietary and only available through APIs and apps.

Which is newer?

Claude Opus 5 is the newest, released Jul 24, 2026. Claude Opus 4.5 came out Nov 24, 2025; GPT-5.1 came out Nov 13, 2025. Knowledge cutoff: GPT-5.1 Sep 30, 2024, Claude Opus 4.5 May 2025, Claude Opus 5 May 2026.

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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