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Comparison · 2 models · Updated Oct 4, 2026

GPT-5 vs Claude Sonnet 4.5

GPT-5 comes out ahead, 60 to 55 on our weighted score, and it is the cheaper option too.

  1. Our pick

    OpenAI

    GPT-5

    Released Aug 7, 2025

    60/100
    • ECI150.0
    • Price$1.25 / $10.00
    • Context400K
    Full specs Remove GPT-5

  2. 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

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-5 is our pick

GPT-5 is the better all-round choice, scoring 60/100 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-5Capabilities Index (ECI): GPT-5 150.0 · Claude Sonnet 4.5 146.8
  • Lowest priceGPT-5GPT-5 $3.44 · Claude Sonnet 4.5 $6.00 per 1M tokens (3:1 blend)
  • Longest contextGPT-5GPT-5 400,000 · Claude Sonnet 4.5 200,000 tokens
  • Widest inputsClaude Sonnet 4.5GPT-5: Text, Images · Claude Sonnet 4.5: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5Claude Sonnet 4.5
CapabilityCapabilities Index (ECI)50%7874
Price25%2413
Inputs & features15%7080
Context window10%4432
Overall100%60/10055/100
02 — Side by side

Every spec in one table

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

GPT-5 vs Claude Sonnet 4.5 specifications side by side
SpecificationGPT-5OpenAIClaude Sonnet 4.5Anthropic
Capability
Capabilities Index (ECI)150.0 (best)146.8
ECI rank#50 of 148 (best)#64 of 148
GPQA DiamondGraduate-level science questions86.2% (best)82.3%
FrontierMath Tiers 1–3Research-level mathematics55.4% (best)23.9%
OTIS Mock AIME 2024–2025Competition mathematics91.4% (best)77.8%
SWE-bench VerifiedFixing real GitHub issues73.6% (best)71.3%
SimpleQA VerifiedShort factual questions50.1% (best)30.7%
Price per million tokens
Input$1.25 (best)$3.00
Output$10.00 (best)$15.00
Cached input$0.125 (best)$0.30
Blended (3:1)$3.44 (best)$6.00
Long-context rateSame rateSame rate
Price sourceOfficial OpenAI APIOfficial Anthropic API
Limits
Context window400,000 tokens (best)200,000 tokens
Max output128,000 tokens (best)64,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoYes
AudioNoNo
VideoNoNo
ReasoningYesminimal · low · medium · highYes
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5claude-sonnet-4-5
API providers2428 (best)
ReleasedAug 7, 2025Sep 29, 2025
Knowledge cutoffSep 30, 2024Jul 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$32.50
  • Claude Sonnet 4.5$60.00
04 — Questions

Which should you choose?

Which is better: GPT-5 or Claude Sonnet 4.5?

GPT-5 is the better all-round choice, scoring 60/100 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, GPT-5 or Claude Sonnet 4.5?

GPT-5 is cheaper at $1.25 input / $10.00 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 $3.44 per million tokens for GPT-5 versus $6.00 for Claude Sonnet 4.5 (1.7× as much).

Which scores higher on benchmarks?

GPT-5 scores higher on the Capabilities Index (ECI): GPT-5 150.0 (#50 of 148) and Claude Sonnet 4.5 146.8 (#64 of 148). On individual benchmarks: GPQA Diamond — GPT-5 86.2%, Claude Sonnet 4.5 82.3%; FrontierMath Tiers 1–3 — GPT-5 55.4%, Claude Sonnet 4.5 23.9%; OTIS Mock AIME 2024–2025 — GPT-5 91.4%, Claude Sonnet 4.5 77.8%; SWE-bench Verified — GPT-5 73.6%, Claude Sonnet 4.5 71.3%; SimpleQA Verified — GPT-5 50.1%, Claude Sonnet 4.5 30.7%.

Which is better for coding?

GPT-5 resolves more real GitHub issues on SWE-bench Verified: GPT-5 73.6% and Claude Sonnet 4.5 71.3%. Both support tool calling for agent workflows.

Which has the bigger context window?

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

Which can read images, PDFs, audio or video?

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

Are any of these open source?

No. GPT-5 and Claude Sonnet 4.5 are proprietary and only available through APIs and apps.

Which is newer?

Claude Sonnet 4.5 is the newest, released Sep 29, 2025. GPT-5 came out Aug 7, 2025. Knowledge cutoff: GPT-5 Sep 30, 2024, Claude Sonnet 4.5 Jul 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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