Claude Opus 5.5 vs GPT-5.6 Terra
Claude Opus 5.5 leads the LLM Stats Score 59.7 to 50.3. GPT-5.6 Terra is 1.8x cheaper per token.
Anthropic · OpenAI · Updated for 2026
Which is better?
Claude Opus 5.5 leads the overall LLM Stats Score 59.7 to 50.3, ranking #1 overall.
In the 10 individual benchmarks reported for both models, Claude Opus 5.5 wins 10; this is a narrower head-to-head signal than the composite indexes.
On price, GPT-5.6 Terra is roughly 1.8x 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.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose Claude Opus 5.5
- overall performance matters — it scores 59.7 and ranks #1 on LLM Stats
- your work emphasizes reasoning and coding — it leads those capability indexes
- you value its reported benchmark strengths — it wins 10 of 10 exact shared results
- you want the most recent training data — it shipped Sep 2026
Choose GPT-5.6 Terra
- cost matters — it's about 1.8x cheaper per token
- you process long inputs — it offers a 1,050,000 token context window
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
31 reported for Claude Opus 5.5 · 45 for GPT-5.6 Terra
Claude Opus 5.5 outperforms in 10 benchmarks (AutomationBench, BenchCAD, BenchCAD (with Python tool), DeepSWE 1.1, FrontierCode 1.1, HealthBench, HealthBench Professional, OSWorld 2.0, SWE-Bench Pro, Terminal-Bench 4.0), while GPT-5.6 Terra is better at 0 benchmarks.
Claude Opus 5.5 significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Opus 5.5 ($4.00/1M tokens) is 2.0x more expensive than GPT-5.6 Terra ($2.00/1M tokens).
For output processing, Claude Opus 5.5 ($20.00/1M tokens) is 1.7x more expensive than GPT-5.6 Terra ($12.00/1M tokens).
In conclusion, Claude Opus 5.5 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 Opus 5.5's 1,000,000 tokens. Both models can generate responses up to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both Claude Opus 5.5 and GPT-5.6 Terra support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Opus 5.5
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 Opus 5.5 was released on 2026-09-22, while GPT-5.6 Terra was released on 2026-07-09.
Claude Opus 5.5 is 3 months newer than GPT-5.6 Terra.
Sep 22, 2026
0 days ago
2mo newerJul 9, 2026
2 months ago
Knowledge Cutoff
When training data ends
Claude Opus 5.5 has a knowledge cutoff of 2026-06-01, while GPT-5.6 Terra has a cutoff of 2026-02-16.
Claude Opus 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-5.6 Terra (2026-02-16).
Jun 2026
4 mo newerFeb 2026
Provider Availability
Claude Opus 5.5 is available from Anthropic. GPT-5.6 Terra is available from OpenAI.
Claude Opus 5.5
GPT-5.6 Terra
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Opus 5.5 and GPT-5.6 Terra side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Opus 5.5 vs GPT-5.6 Terra.