GPT-5.6 Terra vs GPT-6 Astra: Specs & Benchmark Comparison
GPT-5.6 Terra and GPT-6 Astra both come from OpenAI, GPT-5.6 Terra was released in July 2026, and GPT-6 Astra followed 2 months later in September 2026.
The two models share 17 published benchmarks. GPT-6 Astra leads on 17 of them. The widest gaps are on ARC-AGI-3, where GPT-6 Astra scores 99.9% against 0.8%; ExploitBench, where GPT-6 Astra scores 100.0% against 52.9%. Averaged across everything we track, GPT-5.6 Terra sits at 59.0% and GPT-6 Astra at 74.4%.
GPT-5.6 Terra is the cheaper API at $2 per million input tokens and $12 per million output tokens, roughly 5 times cheaper than GPT-6 Astra at $10 and $50. Both accept a context window of about 1M tokens. Both accept text and images as input.
| Characteristic | GPT-5.6 Terra | GPT-6 Astra |
|---|---|---|
| Company | OpenAI | OpenAI |
| Release Date | July 9, 2026 | September 4, 2026 |
| Parameters | — | — |
| Multimodal | Yes | Yes |
| Context (input) | 1.1M | 1.1M |
| Context (output) | 128K | 128K |
| Input Price / 1M | $2.00 | $10.00 |
| Output Price / 1M | $12.00 | $50.00 |
| Average Score | 59.0% | 74.4% |
| Benchmarks | ||
| ARC-AGI-3 | 0.8% | 99.9% |
| ExploitBench | 52.9% | 100.0% |
| Terminal-Bench 4.0 | 21.5% | 57.7% |
| FrontierMath Tier 4 (v2) | 68.3% | 97.6% |
| SEC-bench Pro | 57.7% | 85.4% |
| AutomationBench | 15.2% | 41.4% |
| OSWorld 2.0 | 50.2% | 72.6% |
| ExploitGym | 23.2% | 42.4% |
| BenchCAD (with Python tool) | 78.2% | 95.9% |
| GeneBench-Pro | 23.3% | 37.8% |
| FrontierCode 1.1 | 41.3% | 53.3% |
| Agents' Last Exam | 50.4% | 59.3% |
| HealthBench Professional | 57.7% | 63.4% |
| LifeSciBench | 56.0% | 60.3% |
| DeepSWE 1.1 | 70.0% | 74.1% |
| BrowseComp | 87.5% | 91.5% |
| GPQA | 92.9% | 96.0% |
Visual Benchmark Comparison
Verdict
Both models show equal results — the choice depends on your specific use case.
Both models show comparable average scores: GPT-5.6 Terra — 0.6, GPT-6 Astra — 0.7.
GPT-5.6 Terra is 4.3x cheaper: input $2.00/1M vs $10.00/1M tokens.
Same context size: 1M tokens.
GPT-6 Astra is newer: released 9/4/2026 vs 7/9/2026.
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Frequently Asked Questions
Which is better for coding — GPT-5.6 Terra or GPT-6 Astra?
Which model is cheaper — GPT-5.6 Terra or GPT-6 Astra?
Which has a larger context window — GPT-5.6 Terra or GPT-6 Astra?
The GPT-5.6 Terra and GPT-6 Astra comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-5.6 Terra or GPT-6 Astra page. See also the complete list of AI model comparisons.