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Claude Sonnet 5.5 vs GPT-5

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 33.8. GPT-5 is 1.2x cheaper per token.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.1 to 33.8, ranking #3 overall.

On price, GPT-5 is roughly 1.2x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Sonnet 5.5 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Sonnet 5.5

  • overall performance matters — it scores 58.1 and ranks #3 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you process long inputs — it offers a 1,000,000 token context window
  • you want the most recent training data — it shipped Sep 2026

Choose GPT-5

  • cost matters — it's about 1.2x cheaper per token

At a glance

The differences that matter most.

Claude Sonnet 5.5
Anthropic
GPT-5
OpenAI
Core performance indexes
LLM Stats Score
58.1
#3
33.8
#104
Reasoning
56.6
#3
34.2
#97
Coding
48.9
#2
26.4
#71
Agents
42.3
#3
9.1
#134
Cost, coverage & limits
Benchmark wins
—
—
Input price
$2.00 / M
$1.25 / M
Output price
$10.00 / M
$10.00 / M
Context window
1,000,000
400,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

4 shared
Index
Claude Sonnet 5.5
GPT-5
Math
36.9#34
31.5#67
Vision
40.1#3
20.8#71
Tool use
33.9#2
16.2#85
Multimodal
40.2#2
27.6#40
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 34 for GPT-5

No common benchmarks found

Claude Sonnet 5.5 and GPT-5don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

GPT-5 costs less

For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) is 1.6x more expensive than GPT-5 ($1.25/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) costs the same as GPT-5 ($10.00/1M tokens).

In conclusion, Claude Sonnet 5.5 is more expensive than GPT-5.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Tue Sep 29 2026 • llm-stats.com
Anthropic
Claude Sonnet 5.5
Input tokens$2.00
Output tokens$10.00
Best providerAnthropic
OpenAI
GPT-5
Input tokens$1.25
Output tokens$10.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Claude Sonnet 5.5 accepts 1,000,000 input tokens compared to GPT-5's 400,000 tokens. Both models can generate responses up to 128,000 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
OpenAI
GPT-5
Input400,000 tokens
Output128,000 tokens
Tue Sep 29 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Sonnet 5.5 and GPT-5 support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Sonnet 5.5

Text
Images
Audio
Video

GPT-5

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude Sonnet 5.5

Proprietary

Closed source

GPT-5

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while GPT-5 was released on 2025-08-07.

Claude Sonnet 5.5 is 14 months newer than GPT-5.

Claude Sonnet 5.5

Sep 28, 2026

1 days ago

1.1yr newer
GPT-5

Aug 7, 2025

1.1 years ago

Knowledge Cutoff

When training data ends

Claude Sonnet 5.5 has a knowledge cutoff of 2026-06-01, while GPT-5 has a cutoff of 2024-09-30.

Claude Sonnet 5.5 has more recent training data (up to 2026-06-01), making it potentially better informed about events through that date compared to GPT-5 (2024-09-30).

Claude Sonnet 5.5

Jun 2026

1.8 yr newer
GPT-5

Sep 2024

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. GPT-5 is available from OpenAI.

Claude Sonnet 5.5

anthropic logo
Anthropic
Input Price:Input: $2.00/1MOutput Price:Output: $10.00/1M

GPT-5

openai logo
OpenAI
Input Price:Input: $1.25/1MOutput Price:Output: $10.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Sonnet 5.5 and GPT-5 side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
GPT-5
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs GPT-5.

Which is better, Claude Sonnet 5.5 or GPT-5?

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 33.8. Claude Sonnet 5.5 is made by Anthropic and GPT-5 is made by OpenAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Sonnet 5.5 compare to GPT-5 in benchmarks?

Claude Sonnet 5.5 scores BenchCAD (with Python tool): 96.3%, ArXivMath (with tools): 95.2%, Global-MMLU: 92.1%, MILU: 91.6%, SWE-bench Multilingual: 90.3%. GPT-5 scores SWE-Lancer (IC-Diamond subset): 100.0%, COLLIE: 99.0%, Tau2 Telecom: 96.7%, OpenAI-MRCR: 2 needle 128k: 95.2%, AIME 2025: 94.6%.

Is Claude Sonnet 5.5 cheaper than GPT-5?

GPT-5 is 1.6x cheaper for input tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output via anthropic. GPT-5 costs $1.25/M input and $10.00/M output via openai.

What are the context window sizes for Claude Sonnet 5.5 and GPT-5?

Claude Sonnet 5.5 supports 1.0M tokens and GPT-5 supports 400K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Sonnet 5.5 and GPT-5?

Key differences include LLM Stats Score (58.1 vs 33.8), context window (1.0M vs 400K), input pricing ($2.00 vs $1.25/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and GPT-5?

Claude Sonnet 5.5 is developed by Anthropic and GPT-5 is developed by OpenAI.

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