MODEL PROOF
GPT-5.6 Terra
BETTER VALUE OPTION
A stored alternative has an equal-or-higher measured score and an equal-or-lower price.
Base context tier shown; inspect the complete context ladder below.
GPT-5.6 Sol · Δ score 8.9 points · 11% lower measured price · $4.00 / 1M tokens
Gemini 3.8 Flash is a further stored option with these losses: 1.1M → 1M context, 128K → 66K max output
- Independent LMArena score
- 1,446.2 ± 4.81 · 28,119 votes
- Context window
- 1.05M
- Maximum output
- 128K
- Input modalities
- file, image, text
- Output modalities
- text
- Published input price
- $2.00 / 1M tokens
- Published output price
- $12.00 / 1M tokens
- Pricing kind
- fixed
- Context tiers
- Tiered by context
Inspect complete billing conditions and endpoint terms below.
Every price dimension · USD per million tokens
| Input | $2.00/M |
|---|---|
| Output | $12.00/M |
| Cached input | $0.200/M |
| Cache write | $2.50/M |
| Cache write 1h | Unknown/M |
| Reasoning | Unknown/M |
| Web search | $0.01/call |
| Batch discount | 50% |
The headline rate does not apply to a long-context workload.
Complete context ladder · 1 tier
| More than 272,000 tokens | $4.00/M in (2×) $18.00/M out $0.400/M cached input $5.00/M cache write |
|---|
Who sells it
The same weights, different shops. Cheapest is not like-for-like when serving precision differs.
7 provider offers · rates, limits and conditions
Rates are USD per million tokens. Endpoint terms can differ even when the quoted price and precision match. A listed parameter is a provider declaration, not a task-success test.
| Seller | Input | Output | Precision | Uptime (1d) |
|---|---|---|---|---|
| OpenAIopenai/flex Endpoint terms
| $1.00 | $6.00 | undeclared | 99.97% |
| Azureazure Endpoint terms
| $2.00 | $12.00 | undeclared | 99.96% |
| OpenAIopenai Endpoint terms
| $2.00 | $12.00 | undeclared | 99.99% |
| Azureazure/us Endpoint terms
| $2.20 | $13.20 | undeclared | 100.00% |
| Amazon Bedrockamazon-bedrock/us-east-1 Endpoint terms
| $2.20 | $13.20 | undeclared | — |
| Azureazure/eu Endpoint terms
| $2.20 | $13.20 | undeclared | 99.92% |
| OpenAIopenai/fast Endpoint terms
| $4.00 | $24.00 | undeclared | 99.99% |
Independent scores
| LMArena Elo | 1446.2xhigh |
|---|
LMArena Elo under CC BY 4.0. Absence of another board is not a score of zero.
Capability
| Context window | 1.1M |
|---|---|
| Max output | 128K |
| Input modes | file, image, text |
| Tool use | yes |
| Reasoning | optional |
| Knowledge cutoff | 2026-02-16 |
| Open weights | no |
Provenance
| Price source | openrouter.ai |
|---|---|
| Fetched | 2026-09-23 |
| Quality data | verified |
| Cross-checked | vendor page |
Our take
editorial — not a measurementCompare Terra and Sol at the same reasoning effort and on the benchmark task relevant to your workload. A general-board result cannot substitute for document performance, and overlapping intervals do not establish a reliable ordering. Use the current proof and benchmark evidence for that comparison. The accepted price table includes a context tier; batch and other delivery modes need their own terms. Missing latency data is not evidence of speed.
Strengths
- Tools, structured outputs and selectable reasoning effort are listed
- The price table separates input, output, cache and context-tier rates
Weaknesses
- Prompt length can change the selected rate
- General and document measurements are different evidence
- Regional or special delivery modes must be checked against their own offer conditions
Reach for it when
- Document and general-task evaluations within an OpenAI stack
- Workloads with measured prompt size and cache reuse
Avoid it if
- You need open weights
- The choice depends on an unverified latency or task-performance advantage
Sources: developers.openai.com
GPT-5.6 Terra is a balanced model in OpenAI's GPT-5.6 series, positioned between the flagship Sol tier and the cost-efficient Luna tier. It is suited for everyday coding, reasoning, and agentic...
Questions this page answers
What does GPT-5.6 Terra cost?
$2.00/M in, $12.00/M out in this catalogue, as of the fetch date on this page. That is the API row, not a subscription.
Does GPT-5.6 Terra have an independent quality score?
GPT-5.6 Terra has an LMArena score in this catalogue.
What beats GPT-5.6 Terra?
GPT-5.6 Sol has an equal-or-higher measured score and an equal-or-lower price.
Does this page use Artificial Analysis scores for GPT-5.6 Terra?
No. Artificial Analysis figures are not published here. Quality on this page is LMArena Elo where a score exists; otherwise the row is unrated.
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[](https://undominated.ai/models/openai__gpt-5.6-terra/)<a href="https://undominated.ai/models/openai__gpt-5.6-terra/"><img src="https://undominated.ai/badge/openai__gpt-5.6-terra.svg" alt="GPT-5.6 Terra — Undominated.ai dominance verdict" height="36"></a>Direct file: https://undominated.ai/badge/openai__gpt-5.6-terra.svg — a static SVG, written by scripts/build-badges.mjs on every build, so the copy you embed is never
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