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Comparison · 2 models · Updated Oct 4, 2026

Claude Sonnet 4.5 vs GPT-5.2

GPT-5.2 comes out ahead, 61 to 55 on our weighted score, and it is the cheaper option too.

  1. Anthropic

    Claude Sonnet 4.5

    Released Sep 29, 2025

    55/100
    • ECI146.8
    • Price$3.00 / $15.00
    • Context200K
    Full specs Remove Claude Sonnet 4.5
  2. Our pick

    OpenAI

    GPT-5.2

    Released Dec 11, 2025

    61/100
    • ECI153.5
    • Price$1.75 / $14.00
    • Context400K
    Full specs Remove GPT-5.2

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-5.2 is our pick

GPT-5.2 is the better all-round choice, scoring 61/100 against Claude Sonnet 4.5 (55). It leads on capability, price and context window. Claude Sonnet 4.5 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT-5.2Capabilities Index (ECI): GPT-5.2 153.5 · Claude Sonnet 4.5 146.8
  • Lowest priceGPT-5.2GPT-5.2 $4.81 · Claude Sonnet 4.5 $6.00 per 1M tokens (3:1 blend)
  • Longest contextGPT-5.2GPT-5.2 400,000 · Claude Sonnet 4.5 200,000 tokens
  • Widest inputsClaude Sonnet 4.5Claude Sonnet 4.5: Text, Images, PDFs · GPT-5.2: Text, Images
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightClaude Sonnet 4.5GPT-5.2
CapabilityCapabilities Index (ECI)50%7483
Price25%1318
Inputs & features15%8070
Context window10%3244
Overall100%55/10061/100
02 — Side by side

Every spec in one table

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

Claude Sonnet 4.5 vs GPT-5.2 specifications side by side
SpecificationClaude Sonnet 4.5AnthropicGPT-5.2OpenAI
Capability
Capabilities Index (ECI)146.8153.5 (best)
ECI rank#64 of 148#38 of 148 (best)
GPQA DiamondGraduate-level science questions82.3%91.4% (best)
FrontierMath Tiers 1–3Research-level mathematics23.9%67.4% (best)
OTIS Mock AIME 2024–2025Competition mathematics77.8%96.1% (best)
SWE-bench VerifiedFixing real GitHub issues71.3%73.8% (best)
SimpleQA VerifiedShort factual questions30.7%37.1% (best)
Price per million tokens
Input$3.00$1.75 (best)
Output$15.00$14.00 (best)
Cached input$0.30$0.175 (best)
Blended (3:1)$6.00$4.81 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Anthropic APIOfficial OpenAI API
Limits
Context window200,000 tokens400,000 tokens (best)
Max output64,000 tokens128,000 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesNo
AudioNoNo
VideoNoNo
ReasoningYesYeslow · medium · high · xhigh
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDclaude-sonnet-4-5gpt-5.2
API providers28 (best)21
ReleasedSep 29, 2025Dec 11, 2025
Knowledge cutoffJul 31, 2025Aug 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.

  • Claude Sonnet 4.5$60.00
  • GPT-5.2$45.50
04 — Questions

Which should you choose?

Which is better: Claude Sonnet 4.5 or GPT-5.2?

GPT-5.2 is the better all-round choice, scoring 61/100 against Claude Sonnet 4.5 (55). It leads on capability, price and context window. Claude Sonnet 4.5 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Claude Sonnet 4.5 or GPT-5.2?

GPT-5.2 is cheaper at $1.75 input / $14.00 output per million tokens (official OpenAI API price). Claude Sonnet 4.5 costs $3.00 input / $15.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $4.81 per million tokens for GPT-5.2 versus $6.00 for Claude Sonnet 4.5 (1.2× as much).

Which scores higher on benchmarks?

GPT-5.2 scores higher on the Capabilities Index (ECI): GPT-5.2 153.5 (#38 of 148) and Claude Sonnet 4.5 146.8 (#64 of 148). Their confidence ranges do not overlap (151.7–155.4 vs 145.3–148.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — GPT-5.2 91.4%, Claude Sonnet 4.5 82.3%; FrontierMath Tiers 1–3 — GPT-5.2 67.4%, Claude Sonnet 4.5 23.9%; OTIS Mock AIME 2024–2025 — GPT-5.2 96.1%, Claude Sonnet 4.5 77.8%; SWE-bench Verified — GPT-5.2 73.8%, Claude Sonnet 4.5 71.3%; SimpleQA Verified — GPT-5.2 37.1%, Claude Sonnet 4.5 30.7%.

Which is better for coding?

GPT-5.2 resolves more real GitHub issues on SWE-bench Verified: GPT-5.2 73.8% and Claude Sonnet 4.5 71.3%. Both support tool calling for agent workflows.

Which has the bigger context window?

GPT-5.2 has the largest context window at 400,000 tokens, against 200,000 for Claude Sonnet 4.5. Maximum output per response: Claude Sonnet 4.5 up to 64,000, GPT-5.2 up to 128,000 tokens.

Which can read images, PDFs, audio or video?

Claude Sonnet 4.5 accepts text, images and PDFs; GPT-5.2 accepts text and images. Claude Sonnet 4.5 handles the widest range of inputs.

Are any of these open source?

No. Claude Sonnet 4.5 and GPT-5.2 are proprietary and only available through APIs and apps.

Which is newer?

GPT-5.2 is the newest, released Dec 11, 2025. Claude Sonnet 4.5 came out Sep 29, 2025. Knowledge cutoff: Claude Sonnet 4.5 Jul 31, 2025, GPT-5.2 Aug 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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