Model Comparison
GPT-5.6 Terra vs o3Which is better in 2026?
GPT-5.6 Terra significantly outperforms across most benchmarks. o3 is 1.6x cheaper per token.
Verdict: GPT-5.6 Terra vs o3 — which is better?
GPT-5.6 Terra (by OpenAI) and o3 (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.
GPT-5.6 Terra outperforms in 4 benchmarks (BrowseComp, FrontierMath, GPQA, MMMU-Pro), while o3 is better at 0 benchmarks. GPT-5.6 Terra significantly outperforms across most benchmarks.
On price, o3 is roughly 1.6x 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 GPT-5.6 Terra if…
- you want the strongest raw capability — it leads on 4 of 4 shared benchmarks
- you process long inputs — it offers a 1,050,000 token context window
- you want the most recent training data — it shipped Jul 2026
Choose o3 if…
- cost matters — it's about 1.6x cheaper per token
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5.6 Terra outperforms in 4 benchmarks (BrowseComp, FrontierMath, GPQA, MMMU-Pro), while o3 is better at 0 benchmarks.
GPT-5.6 Terra significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.6 Terra ($2.50/1M tokens) is 1.3x more expensive than o3 ($2.00/1M tokens).
For output processing, GPT-5.6 Terra ($15.00/1M tokens) is 1.9x more expensive than o3 ($8.00/1M tokens).
In conclusion, GPT-5.6 Terra is more expensive than o3.*
* 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 o3's 200,000 tokens. GPT-5.6 Terra can generate longer responses up to 128,000 tokens, while o3 is limited to 100,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5.6 Terra and o3 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.6 Terra
o3
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
GPT-5.6 Terra was released on 2026-07-09, while o3 was released on 2025-04-16.
GPT-5.6 Terra is 15 months newer than o3.
Jul 9, 2026
1 weeks ago
1.2yr newerApr 16, 2025
1.3 years ago
Knowledge Cutoff
When training data ends
GPT-5.6 Terra has a knowledge cutoff of 2026-02-16, while o3 has a cutoff of 2024-05-31.
GPT-5.6 Terra has more recent training data (up to 2026-02-16), making it potentially better informed about events through that date compared to o3 (2024-05-31).
Feb 2026
1.8 yr newerMay 2024
Provider Availability
GPT-5.6 Terra is available from OpenAI. o3 is available from OpenAI.
GPT-5.6 Terra
o3
Outputs Comparison
Key Takeaways
o3
View detailsOpenAI
GPT-5.6 Terrao3Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against GPT-5.6 Terra and o3 side-by-side, then vote on the output you prefer.
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FAQ
Common questions about GPT-5.6 Terra vs o3.