ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT-5.1 vs Claude Opus 5

Claude Opus 5 comes out ahead, 66 to 60 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. 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

  3. Add a model

    Make it a three-way comparison.

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). It leads on capability, inputs & features 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 · GPT-5.1 149.7
  • Lowest priceGPT-5.1GPT-5.1 $3.44 · 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 tokens
  • Widest inputsClaude Opus 5GPT-5.1: Text, Images · Claude Opus 5: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.1Claude Opus 5
CapabilityCapabilities Index (ECI)50%7894
Price25%242
Inputs & features15%7080
Context window10%4460
Overall100%60/10066/100
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 5 specifications side by side
SpecificationGPT-5.1OpenAIClaude Opus 5Anthropic
Capability
Capabilities Index (ECI)149.7162.9 (best)
ECI rank#52 of 148#5 of 148 (best)
GPQA DiamondGraduate-level science questions87.6%93.9% (best)
FrontierMath Tiers 1–3Research-level mathematics—85.6%
OTIS Mock AIME 2024–2025Competition mathematics88.6%98.9% (best)
SWE-bench VerifiedFixing real GitHub issues68.0%—
SimpleQA VerifiedShort factual questions48.0%59.9% (best)
Price per million tokens
Input$1.25 (best)$5.00
Output$10.00 (best)$25.00
Cached input$0.125 (best)$0.50
Blended (3:1)$3.44 (best)$10.00
Long-context rateSame rateSame rate
Price sourceOfficial OpenAI APIOfficial Anthropic API
Limits
Context window400,000 tokens1,000,000 tokens (best)
Max output128,000 tokens128,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoYes
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · highYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5.1claude-opus-5
API providers2135 (best)
ReleasedNov 13, 2025Jul 24, 2026
Knowledge cutoffSep 30, 2024May 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 5$100.00
04 — Questions

Which should you choose?

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

Claude Opus 5 is the better all-round choice, scoring 66/100 against GPT-5.1 (60). It leads on capability, inputs & features 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 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 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 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) and GPT-5.1 149.7 (#52 of 148). Their confidence ranges do not overlap (160.2–166.7 vs 148.3–151.1), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Opus 5 93.9%, GPT-5.1 87.6%; OTIS Mock AIME 2024–2025 — Claude Opus 5 98.9%, GPT-5.1 88.6%; SimpleQA Verified — Claude Opus 5 59.9%, GPT-5.1 48.0%.

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. Both 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. Maximum output per response: GPT-5.1 up to 128,000, 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 5 accepts text, images and PDFs. Claude Opus 5 handles the widest range of inputs.

Are any of these open source?

No. GPT-5.1 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. GPT-5.1 came out Nov 13, 2025. Knowledge cutoff: GPT-5.1 Sep 30, 2024, 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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