Model Comparison
Claude 3.5 Haiku vs GPT-5.1 ThinkingWhich is better in 2026?
GPT-5.1 Thinking significantly outperforms across most benchmarks. Claude 3.5 Haiku is 2.1x cheaper per token.
Verdict: Claude 3.5 Haiku vs GPT-5.1 Thinking — which is better?
Claude 3.5 Haiku (by Anthropic) and GPT-5.1 Thinking (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.
Claude 3.5 Haiku outperforms in 0 benchmarks, while GPT-5.1 Thinking is better at 2 benchmarks (GPQA, SWE-Bench Verified). GPT-5.1 Thinking significantly outperforms across most benchmarks.
On price, Claude 3.5 Haiku is roughly 2.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.1 Thinking also accepts a larger context window (400,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Claude 3.5 Haiku if…
- cost matters — it's about 2.1x cheaper per token
Choose GPT-5.1 Thinking if…
- you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
- you process long inputs — it offers a 400,000 token context window
- you want the most recent training data — it shipped Nov 2025
Performance Benchmarks
Comparative analysis across standard metrics
Claude 3.5 Haiku outperforms in 0 benchmarks, while GPT-5.1 Thinking is better at 2 benchmarks (GPQA, SWE-Bench Verified).
GPT-5.1 Thinking significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Claude 3.5 Haiku ($0.80/1M tokens) is 1.6x cheaper than GPT-5.1 Thinking ($1.25/1M tokens).
For output processing, Claude 3.5 Haiku ($4.00/1M tokens) is 2.5x cheaper than GPT-5.1 Thinking ($10.00/1M tokens).
In conclusion, GPT-5.1 Thinking is more expensive than Claude 3.5 Haiku.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.1 Thinking accepts 400,000 input tokens compared to Claude 3.5 Haiku's 200,000 tokens. Claude 3.5 Haiku can generate longer responses up to 200,000 tokens, while GPT-5.1 Thinking is limited to 128,000 tokens.
Input Capabilities
Supported data types and modalities
GPT-5.1 Thinking supports multimodal inputs, whereas Claude 3.5 Haiku does not.
GPT-5.1 Thinking can handle both text and other forms of data like images, making it suitable for multimodal applications.
Claude 3.5 Haiku
GPT-5.1 Thinking
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 3.5 Haiku was released on 2024-10-22, while GPT-5.1 Thinking was released on 2025-11-12.
GPT-5.1 Thinking is 13 months newer than Claude 3.5 Haiku.
Oct 22, 2024
1.7 years ago
Nov 12, 2025
7 months ago
1.1yr newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Claude 3.5 Haiku is available from Bedrock, Google, Anthropic. GPT-5.1 Thinking is available from OpenAI.
Claude 3.5 Haiku
GPT-5.1 Thinking
Outputs Comparison
Key Takeaways
Claude 3.5 Haiku
View detailsAnthropic
Detailed Comparison
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FAQ
Common questions about Claude 3.5 Haiku vs GPT-5.1 Thinking.