GPT-5.6 Terra vs GPT-6 Astra
At a Glance
| Compare |  GPT-5.6 TerraOpenAI | GPT-6 AstraOpenAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | #13 of 4674.9 score · 3/3 sources · complete | #6 of 4684.4 score · 3/3 sources · complete |
| CostLower is better · Published-token output estimate | #35 of 44$0.266 per LiveBench case | #41 of 44$0.520 per LiveBench case |
| EfficiencyHigher is better · MM Efficiency v1.5 | #23 of 3851.5 score · 3/3 sources · complete | #27 of 3849.2 score · 3/3 sources · complete |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $2.00Openai ↗ · Sep 3, 2026 | $10.00Openai ↗ · Sep 4, 2026 |
| Output priceFrom · USD / 1M tokens | $12.00Openai ↗ · Sep 3, 2026 | $50.00Openai ↗ · Sep 4, 2026 |
| Context windowMaximum documented tokens | 1,050K | 1,050K |
| Model facts checked | Aug 28, 2026View model evidence → | Sep 4, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
| Benchmark | GPT-5.6 Terra | GPT-6 Astra |
|---|---|---|
| ARC-AGI-1verified-v1-ba05d69f6453 · verified_score · leader | 96.5098% of row best · percent · GPT-5.6 Terra (Max) | 98.50100% of row best · percent · GPT-6 Astra (XHigh) |
| ARC-AGI-2verified-v2-6c676fa3e9af · verified_score · leader | 83.9088% of row best · percent · GPT-5.6 Terra (Max) | 95.00100% of row best · percent · GPT-6 Astra (Max) |
| LMArena Agent Arenaagent-2026-09-15-d25aabda0010 · outcome_score · leader | 1.4491% of row best · score · GPT 5.6 Terra (xHigh); 95% CI [0.32735411, 2.55262103]; sessions 20301; observations 1231027; rank 23 | 11.54100% of row best · score · GPT 6 Astra (Max); 95% CI [9.43393746, 13.63932109]; sessions 10372; observations 782334; rank 2 |
| LMArena Document Arenadocument-2026-09-13-d25aabda0010 · arena_rating · statistical tie | 1,471.58100% of row best · rating · gpt-5.6-terra-xhigh; 95% CI [1463.31179298, 1479.85049651]; votes 5787; rank 13 | 1,467.52100% of row best · rating · gpt-6-astra-max; 95% CI [1453.25995337, 1481.78626802]; votes 1621; rank 16 |
| LMArena Text Arenatext-2026-09-13-d25aabda0010 · arena_rating · statistical tie | 1,446.22100% of row best · rating · gpt-5.6-terra-xhigh; 95% CI [1441.41414497, 1451.02563541]; votes 28119; rank 52 | 1,443.72100% of row best · rating · gpt-6-astra-max; 95% CI [1432.08094427, 1455.36783662]; votes 2693; rank 59 |
| LMArena Vision Arenavision-2026-09-13-d25aabda0010 · arena_rating · statistical tie | 1,269.9099% of row best · rating · gpt-5.6-terra-xhigh; 95% CI [1261.54272100, 1278.25950723]; votes 7726; rank 36 | 1,278.58100% of row best · rating · gpt-6-astra-max; 95% CI [1261.64778832, 1295.50325714]; votes 1367; rank 30 |
| LiveBench2026-06-25 · overall · leader | 82.3195% of row best · percent · gpt-5.6-terra-max · 22,145 output tokens / case | 86.47100% of row best · percent · gpt-6-astra-max · 10,407 output tokens / case |
| ToneBench2026-09-11-10-task-4ef099199c9c · overall_score · unverified | 86.39100% of row best · points · GPT-5.6 Terra (ultra) · 11,336 output tokens / case | 86.21100% of row best · points · GPT-6 Astra (max) · 14,778 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above · 3 ties | 0 benchmark wins | 4 benchmark winsOverall lead |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Quality Versus Estimated Output Cost
Side-by-Side Facts
| Field | GPT-5.6 Terra | GPT-6 Astra |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Family | Gpt 5 6 | Gpt 6 |
| Model | GPT-5.6 Terra | GPT-6 Astra |
| Version | GPT-5.6 Terra | GPT-6 Astra |
| Lifecycle | active | active |
| Released | Unknown | 2026-09-03 |
| Knowledge cutoff | 2026-02-16 | 2026-04-30 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,050K | 1,050K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Openai (Standard), Openrouter (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, computer-use, generation, reasoning, research, tools |
GPT-5.6 Terra Capabilities
GPT-6 Astra Capabilities
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Primary Evidence
Sources and Freshness
Questions
GPT-5.6 Terra vs GPT-6 Astra FAQs
Is GPT-5.6 Terra or GPT-6 Astra better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-5.6 Terra and GPT-6 Astra, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, GPT-5.6 Terra or GPT-6 Astra?+
GPT-5.6 Terra is $2.00 and GPT-6 Astra is $10.00 per million tokens, so GPT-5.6 Terra is cheaper on this metric. GPT-5.6 Terra is $12.00 and GPT-6 Astra is $50.00 per million tokens, so GPT-5.6 Terra is cheaper on this metric.
Which has a larger context window, GPT-5.6 Terra or GPT-6 Astra?+
Neither model has a larger sourced context window in this comparison. GPT-5.6 Terra is 1,050K and GPT-6 Astra is 1,050K.
Which performs better in benchmarks, GPT-5.6 Terra or GPT-6 Astra?+
GPT-6 Astra leads the current overall benchmark count. The result uses 7 protocol-matched benchmarks from 3 publishers; it is not a universal quality score.
Can GPT-5.6 Terra or GPT-6 Astra be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. GPT-5.6 Terra is not marked open weight; GPT-6 Astra is not marked open weight.
Can GPT-5.6 Terra and GPT-6 Astra understand images?+
GPT-5.6 Terra is documented with image input; GPT-6 Astra is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-5.6 Terra or GPT-6 Astra?+
Neither has a larger sourced maximum output. GPT-5.6 Terra is 128K and GPT-6 Astra is 128K.
Do GPT-5.6 Terra and GPT-6 Astra support reasoning and tool use?+
GPT-5.6 Terra: reasoning, tool calling, and image input. GPT-6 Astra: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, GPT-5.6 Terra or GPT-6 Astra?+
GPT-5.6 Terra has 2 sourced provider routes; GPT-6 Astra has 2, a tie.
Which offers better value, GPT-5.6 Terra or GPT-6 Astra?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.