Claude Sonnet 4.5 vs GPT-4o
Claude Sonnet 4.5 significantly outperforms across most benchmarks. GPT-4o is 1.4x cheaper per token.
Anthropic · OpenAI · Updated for 2026
Which is better?
Claude Sonnet 4.5 outperforms in 1 benchmarks (GPQA), while GPT-4o is better at 0 benchmarks. Claude Sonnet 4.5 significantly outperforms across most benchmarks.
On price, GPT-4o is roughly 1.4x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Claude Sonnet 4.5 also accepts a larger context window (200,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current benchmark, pricing, and model metadata for 2026.
Choose Claude Sonnet 4.5
- you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
- you process long inputs — it offers a 200,000 token context window
- you want the most recent training data — it shipped Sep 2025
Choose GPT-4o
- cost matters — it's about 1.4x cheaper per token
At a glance
The differences that matter most.
Performance Benchmarks
Comparative analysis across standard metrics
Claude Sonnet 4.5 outperforms in 1 benchmarks (GPQA), while GPT-4o is better at 0 benchmarks.
Claude Sonnet 4.5 significantly outperforms across most benchmarks.
Arena Performance
Playground indexes and blind preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Sonnet 4.5 ($3.00/1M tokens) is 1.2x more expensive than GPT-4o ($2.50/1M tokens).
For output processing, Claude Sonnet 4.5 ($15.00/1M tokens) is 1.5x more expensive than GPT-4o ($10.00/1M tokens).
In conclusion, Claude Sonnet 4.5 is more expensive than GPT-4o.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Claude Sonnet 4.5 accepts 200,000 input tokens compared to GPT-4o's 128,000 tokens. Claude Sonnet 4.5 can generate longer responses up to 64,000 tokens, while GPT-4o is limited to 4,096 tokens.
Input Capabilities
Supported data types and modalities
Both Claude Sonnet 4.5 and GPT-4o support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Sonnet 4.5
GPT-4o
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Sonnet 4.5 was released on 2025-09-29, while GPT-4o was released on 2024-05-13.
Claude Sonnet 4.5 is 17 months newer than GPT-4o.
Sep 29, 2025
11 months ago
1.4yr newerMay 13, 2024
2.3 years ago
Knowledge Cutoff
When training data ends
Claude Sonnet 4.5 has a documented knowledge cutoff of 2025-01-31, while GPT-4o's cutoff date is not specified.
We can confirm Claude Sonnet 4.5's training data extends to 2025-01-31, but cannot make a direct comparison without GPT-4o's cutoff date.
Jan 2025
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Provider Availability
Claude Sonnet 4.5 is available from Anthropic. GPT-4o is available from Azure, OpenAI.
Claude Sonnet 4.5
GPT-4o
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Sonnet 4.5 and GPT-4o side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Sonnet 4.5 vs GPT-4o.