Model Comparison

Claude Opus 4.5 vs GPT-5.3 ChatWhich is better in 2026?

Comparing Claude Opus 4.5 and GPT-5.3 Chat across benchmarks, pricing, and capabilities.

Verdict: Claude Opus 4.5 vs GPT-5.3 Chat — which is better?

Claude Opus 4.5 (by Anthropic) and GPT-5.3 Chat (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

On price, GPT-5.3 Chat is roughly 2.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Opus 4.5 also accepts a larger context window (200,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Claude Opus 4.5 if…

  • you process long inputs — it offers a 200,000 token context window

Choose GPT-5.3 Chat if…

  • cost matters — it's about 2.1x cheaper per token
  • you want the most recent training data — it shipped Mar 2026
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Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Claude Opus 4.5 and GPT-5.3 Chatdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.3 Chat costs less

For input processing, Claude Opus 4.5 ($5.00/1M tokens) is 2.9x more expensive than GPT-5.3 Chat ($1.75/1M tokens).

For output processing, Claude Opus 4.5 ($25.00/1M tokens) is 1.8x more expensive than GPT-5.3 Chat ($14.00/1M tokens).

In conclusion, Claude Opus 4.5 is more expensive than GPT-5.3 Chat.*

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

Lowest available price from all providers
Mon Jun 15 2026 • llm-stats.com
Anthropic
Claude Opus 4.5
Input tokens$5.00
Output tokens$25.00
Best providerAnthropic
OpenAI
GPT-5.3 Chat
Input tokens$1.75
Output tokens$14.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Claude Opus 4.5 accepts 200,000 input tokens compared to GPT-5.3 Chat's 128,000 tokens. Claude Opus 4.5 can generate longer responses up to 64,000 tokens, while GPT-5.3 Chat is limited to 16,384 tokens.

Anthropic
Claude Opus 4.5
Input200,000 tokens
Output64,000 tokens
OpenAI
GPT-5.3 Chat
Input128,000 tokens
Output16,384 tokens
Mon Jun 15 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Opus 4.5 and GPT-5.3 Chat support multimodal inputs.

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

Claude Opus 4.5

Text
Images
Audio
Video

GPT-5.3 Chat

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 Opus 4.5

Proprietary

Closed source

GPT-5.3 Chat

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 4.5 was released on 2025-11-24, while GPT-5.3 Chat was released on 2026-03-04.

GPT-5.3 Chat is 3 months newer than Claude Opus 4.5.

Claude Opus 4.5

Nov 24, 2025

6 months ago

GPT-5.3 Chat

Mar 4, 2026

3 months ago

3mo newer

Knowledge Cutoff

When training data ends

Claude Opus 4.5 has a knowledge cutoff of 2025-03-31, while GPT-5.3 Chat has a cutoff of 2025-08-31.

GPT-5.3 Chat has more recent training data (up to 2025-08-31), making it potentially better informed about events through that date compared to Claude Opus 4.5 (2025-03-31).

Claude Opus 4.5

Mar 2025

GPT-5.3 Chat

Aug 2025

5 mo newer

Provider Availability

Claude Opus 4.5 is available from Anthropic. GPT-5.3 Chat is available from OpenAI.

Claude Opus 4.5

anthropic logo
Anthropic
Input Price:Input: $5.00/1MOutput Price:Output: $25.00/1M

GPT-5.3 Chat

openai logo
OpenAI
Input Price:Input: $1.75/1MOutput Price:Output: $14.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic
Larger context window (200,000 tokens)
OpenAI
Less expensive input tokens
Less expensive output tokens

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Opus 4.5
OpenAI
GPT-5.3 Chat

FAQ

Common questions about Claude Opus 4.5 vs GPT-5.3 Chat.

Which is better, Claude Opus 4.5 or GPT-5.3 Chat?

Claude Opus 4.5 (Anthropic) and GPT-5.3 Chat (OpenAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Claude Opus 4.5 compare to GPT-5.3 Chat in benchmarks?

Claude Opus 4.5 scores Tau2 Telecom: 98.2%, MMMLU: 90.8%, Tau2 Retail: 88.9%, GPQA: 87.0%, SWE-Bench Verified: 80.9%. GPT-5.3 Chat scores HealthBench: 54.1%, HealthBench Hard: 25.9%.

Is Claude Opus 4.5 cheaper than GPT-5.3 Chat?

GPT-5.3 Chat is 2.9x cheaper for input tokens. Claude Opus 4.5 costs $5.00/M input and $25.00/M output via anthropic. GPT-5.3 Chat costs $1.75/M input and $14.00/M output via openai.

What are the context window sizes for Claude Opus 4.5 and GPT-5.3 Chat?

Claude Opus 4.5 supports 200K tokens and GPT-5.3 Chat supports 128K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Opus 4.5 and GPT-5.3 Chat?

Key differences include context window (200K vs 128K), input pricing ($5.00 vs $1.75/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 4.5 and GPT-5.3 Chat?

Claude Opus 4.5 is developed by Anthropic and GPT-5.3 Chat is developed by OpenAI.

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