Model Comparison
Claude Sonnet 5 vs GPT-5.6 TerraWhich is better in 2026?
Both models are evenly matched across the benchmarks. GPT-5.6 Terra is 1.1x cheaper per token.
Verdict: Claude Sonnet 5 vs GPT-5.6 Terra — which is better?
Claude Sonnet 5 (by Anthropic) and GPT-5.6 Terra (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 Sonnet 5 outperforms in 4 benchmarks (GDP.pdf, GDPval-AA, HealthBench Professional, Toolathlon), while GPT-5.6 Terra is better at 4 benchmarks (AutomationBench, BenchCAD, BrowseComp, SWE-Bench Pro). Both models are evenly matched across the benchmarks.
On price, GPT-5.6 Terra is roughly 1.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.6 Terra also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Claude Sonnet 5 if…
- you want predictable pricing at $3.00/M input and $15.00/M output
Choose GPT-5.6 Terra if…
- cost matters — it's about 1.1x cheaper per token
- you process long inputs — it offers a 1,050,000 token context window
- you want the most recent training data — it shipped Jul 2026
Performance Benchmarks
Comparative analysis across standard metrics
Claude Sonnet 5 outperforms in 4 benchmarks (GDP.pdf, GDPval-AA, HealthBench Professional, Toolathlon), while GPT-5.6 Terra is better at 4 benchmarks (AutomationBench, BenchCAD, BrowseComp, SWE-Bench Pro).
Both models are evenly matched across the benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Sonnet 5 ($3.00/1M tokens) is 1.2x more expensive than GPT-5.6 Terra ($2.50/1M tokens).
For output processing, Claude Sonnet 5 ($15.00/1M tokens) costs the same as GPT-5.6 Terra ($15.00/1M tokens).
In conclusion, Claude Sonnet 5 is more expensive than GPT-5.6 Terra.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.6 Terra accepts 1,050,000 input tokens compared to Claude Sonnet 5's 1,000,000 tokens. GPT-5.6 Terra can generate longer responses up to 128,000 tokens, while Claude Sonnet 5 is limited to 64,000 tokens.
Input Capabilities
Supported data types and modalities
Both Claude Sonnet 5 and GPT-5.6 Terra support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Sonnet 5
GPT-5.6 Terra
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 5 was released on 2026-06-30, while GPT-5.6 Terra was released on 2026-07-09.
GPT-5.6 Terra is 0 month newer than Claude Sonnet 5.
Jun 30, 2026
2 weeks ago
Jul 9, 2026
1 weeks ago
1w newerKnowledge Cutoff
When training data ends
GPT-5.6 Terra has a documented knowledge cutoff of 2026-02-16, while Claude Sonnet 5's cutoff date is not specified.
We can confirm GPT-5.6 Terra's training data extends to 2026-02-16, but cannot make a direct comparison without Claude Sonnet 5's cutoff date.
—
Feb 2026
Provider Availability
Claude Sonnet 5 is available from Anthropic. GPT-5.6 Terra is available from OpenAI.
Claude Sonnet 5
GPT-5.6 Terra
Outputs Comparison
Key Takeaways
Claude Sonnet 5
View detailsAnthropic
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Claude Sonnet 5 and GPT-5.6 Terra side-by-side, then vote on the output you prefer.
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FAQ
Common questions about Claude Sonnet 5 vs GPT-5.6 Terra.