text model comparison
GPT-6.1 Terra vs GPT-6 Luna
GPT-6.1 Terra and GPT-6 Luna are both current text models, from OpenAI. GPT-6 Luna is 90% cheaper per 1M input tokens than GPT-6.1 Terra, $0.10 vs $1. On Arena WebDev, GPT-6.1 Terra scores 1673 Elo and GPT-6 Luna 1579 Elo (Arena, measured October 28, 2026). Both accept 1,050,000 tokens of context.
- Higher Arena WebDev
- GPT-6.1 Terra1673 Elo against 1579 Elo
- Lower price per 1M input tokens
- GPT-6 Luna$0.10 against $1
- Newer release
- GPT-6.1 TerraOct 2026 against Sep 2026
Data verified November 3, 2026 · Dataset 2026-11-03
Side by side
GPT-6.1 Terra and GPT-6 Luna, line by line
Prices in effect today, compared at the same tier wherever both list one. The better value in each row is highlighted.
| Fact | GPT-6.1 Terra | GPT-6 Luna |
|---|---|---|
| Price | ||
| Price per 1M input tokens | $1 | $0.10 (better) |
| Price per 1M output tokens | $5 | $0.50 (better) |
| Independent benchmarks | ||
| Arena WebDev | 1673 Elo (#10 of 45) (better) | 1579 Elo (#28 of 45) |
| FrontierMath Tiers 1-3 (v2) | 90.9% (#4 of 42) (better) | 78.9% (#17 of 42) |
| GPQA Diamond | 94.3% (#7 of 41) (better) | 90.5% (#26 of 41) |
| SimpleQA Verified | 57.3% (#15 of 38) (better) | 41.4% (#28 of 38) |
| Arena Text | Not measured | 1441 Elo (#37 of 51) |
| Specs | ||
| Provider | OpenAI | OpenAI |
| Release date | October 26, 2026 | September 22, 2026 |
| Access | API only | API only |
| Context window | 1,050,000 tokens | 1,050,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Input | text, image | text, image |
| Output | text | text |
Charts
Against every current text model
Where GPT-6.1 Terra and GPT-6 Luna land among the current models of their task, on every independent benchmark, on price and on context.
Where each stands
On Arena WebDev, GPT-6.1 Terra ranks #10 and GPT-6 Luna #28 of 45 current models. Each bar is the share of current models it beats: on score, price and context.
Independent benchmarks
Arena Text
GPT-6.1 Terra: Not scored
GPT-6 Luna:#37of 51
1,441 Elo · ahead of 26%
Arena WebDev
GPT-6.1 Terra:#10of 45
1,673 Elo · ahead of 80%
GPT-6 Luna:#28of 45
1,579 Elo · ahead of 39%
FrontierMath Tiers 1-3 (v2)
GPT-6.1 Terra:#4of 42
90.9% · ahead of 93%
GPT-6 Luna:#17of 42
78.9% · ahead of 61%
GPQA Diamond
GPT-6.1 Terra:#7of 41
94.3% · ahead of 83%
GPT-6 Luna:#26of 41
90.5% · ahead of 35%
SimpleQA Verified
GPT-6.1 Terra:#15of 38
57.3% · ahead of 62%
GPT-6 Luna:#28of 38
41.4% · ahead of 27%
Price and context
Price per 1M input tokens
GPT-6.1 Terra:#21of 52
$1 · cheaper than 59%
GPT-6 Luna:#1of 52
$0.10 · cheaper than 96%
Price per 1M output tokens
GPT-6.1 Terra:#27of 52
$5 · cheaper than 49%
GPT-6 Luna:#3of 52
$0.50 · cheaper than 92%
Context window
GPT-6.1 Terra:#1of 64
1.05M tokens · longer than 86%
GPT-6 Luna:#1of 64
1.05M tokens · longer than 86%
Quality against price
GPT-6 Luna scores 1,441 at $0.2 (blended price per 1M tokens). The line joins the current models no other beats on both price and Arena Text score; hover any point to name it.
Quality against price: the data
| Model | Provider | Blended price per 1M tokens | Arena Text (Elo) |
|---|---|---|---|
| Gemini 4 Argon | $4 | 1,520 | |
| Claude Opus 5.5 | Anthropic | $8 | 1,509 |
| Muse Wonder | Meta | $8 | 1,507 |
| Claude Fable 5 | Anthropic | $20 | 1,504 |
| Claude Fable 5.1 | Anthropic | $20 | 1,504 |
| Gemini 3.8 Flash | $1.50 | 1,496 | |
| Muse Spark 1.3 | Meta | $2 | 1,495 |
| Claude Opus 5 | Anthropic | $10 | 1,492 |
| Kimi K3 | Moonshot Kimi | $6 | 1,488 |
| GPT-5.6 Sol | OpenAI | $8 | 1,485 |
| Gemini 3.6 Flash | $3 | 1,483 | |
| GPT-5.5 | OpenAI | $11 | 1,482 |
| Claude Opus 4.8 | Anthropic | $10 | 1,482 |
| Qwen3.8-Max | Alibaba Qwen | $3 | 1,482 |
| GPT-6.1 Sol | OpenAI | $4 | 1,481 |
| GLM-5.3 | Z.ai | $2.15 | 1,481 |
| MiMo-V2.6-Pro | Xiaomi MiMo | $0.54 | 1,480 |
| Claude Sonnet 5.5 | Anthropic | $4 | 1,477 |
| GLM-5.3-Flash | Z.ai | $0.24 | 1,477 |
| GPT-6 Astra | OpenAI | $20 | 1,476 |
| DeepSeek-V4.1-Flash | DeepSeek | $0.52 | 1,476 |
| GPT-5.4 | OpenAI | $5.63 | 1,475 |
| Gemini 3 Flash Preview | $1.13 | 1,473 | |
| Grok 4.20 | xAI | $1.56 | 1,472 |
| GPT-5.6 Terra | OpenAI | $4.50 | 1,467 |
| Grok 4.5 | xAI | $3 | 1,465 |
| DeepSeek-V4-Pro | DeepSeek | $1.98 | 1,465 |
| Claude Sonnet 5 | Anthropic | $4 | 1,462 |
| GPT-6 Sol | OpenAI | $4 | 1,458 |
| Gemini 3.5 Flash-Lite | $0.85 | 1,456 | |
| Grok 4.6 | xAI | $3 | 1,455 |
| GPT-5.6 Luna | OpenAI | $0.45 | 1,453 |
| MiMo-V2.6-Flash | Xiaomi MiMo | $0.18 | 1,448 |
| Step 5 Preview | StepFun | $1.43 | 1,448 |
| Grok 4.3 | xAI | $1.56 | 1,442 |
| GPT-6 Luna | OpenAI | $0.20 | 1,441 |
| Grok 4.7 | xAI | $3 | 1,441 |
| Mistral Large 4 | Mistral AI | $1.05 | 1,432 |
| Claude Haiku 5.5 | Anthropic | $0.20 | 1,425 |
| GPT-4.1 | OpenAI | $3.50 | 1,415 |
| Solar Pro 4 | Upstage | $0.52 | 1,388 |
| GPT-4.1 mini | OpenAI | $0.70 | 1,383 |
| GPT-4.1 nano | OpenAI | $0.18 | 1,322 |
Cost
What each costs
Example workloads at each provider's listed rates, then every other rate either one lists. The cheaper figure in each row is highlighted.
The same work, priced
For 10M input and 2M output tokens, GPT-6.1 Terra costs 10 times as much as GPT-6 Luna, at each provider's listed rates.
10M input and 2M output tokens
GPT-6.1 Terra costs 10× as much
- GPT-6.1 Terra
- $20
- GPT-6 Luna
- $2
The same, with 9M of the input tokens cached
GPT-6.1 Terra costs 9.6× as much
- GPT-6.1 Terra
- $11.45
- GPT-6 Luna
- $1.19
| Workload or rate | GPT-6.1 Terra | GPT-6 Luna |
|---|---|---|
| Example workloads | ||
| 10M input and 2M output tokens | $20 | $2 (better) |
| The same, with 9M of the input tokens cached | $11.45 | $1.19 (better) |
| Other listed rates | ||
| 1M input tokens, cached | $0.05 | $0.01 (better) |
| 1M input tokens, prompts over 272K tokens | $2 | $0.20 (better) |
| 1M output tokens, prompts over 272K tokens | $7.50 | $0.75 (better) |
Your own bill will differ. These figures use list prices and example workloads. The AI Model Cost Audit reviews your real usage, shortlists models that score as well for each task for less, and estimates the savings.
Launch price $100, regular price $150
Verdict
When to choose each
GPT-6.1 Terra
Where it leads
- Higher Arena WebDev score, 1673 Elo vs 1579 Elo
- Higher FrontierMath Tiers 1-3 (v2) score, 90.9% vs 78.9%
- Higher GPQA Diamond score, 94.3% vs 90.5%
- Higher SimpleQA Verified score, 57.3% vs 41.4%
Best for
- Computer-use and tool-calling agents at half GPT-6.1 Sol's price
- High-volume reasoning work that stays under the 272K long-context threshold
Watch out for
- Prompts over 272,000 input tokens bill the whole request at $2 input and $7.50 output per 1M tokens
- Reads text and images only: audio and video input are not supported
GPT-6 Luna
Where it leads
- Lower input and output prices, $0.10 and $0.50 vs $1 and $5 per 1M tokens
- Cheaper cached input, $0.01 vs $0.05 per 1M tokens
Best for
- High-volume summarisation, extraction and routing
- Long-context budget work, where the 272k threshold is more forgiving than Haiku 5.5's 100k
Watch out for
- Prompts over 272,000 tokens are rebilled at $0.20 input and $0.75 output for the whole request
- A twentieth of GPT-6 Sol's price reflects a capability gap, not a discount on the same model
From benchmark to production
Building on GPT-6.1 Terra or GPT-6 Luna?
Public scores rarely hold on your own data. We test both models on your real tasks, then build the agent or pipeline around the one that wins.
AI Model Cost AuditLaunch price $100, regular price $150What the audit includes
FAQ
GPT-6.1 Terra vs GPT-6 Luna FAQ
Which is cheaper, GPT-6.1 Terra or GPT-6 Luna?
GPT-6 Luna is 90% cheaper per 1M input tokens than GPT-6.1 Terra, $0.10 vs $1. For 10M input and 2M output tokens, GPT-6.1 Terra costs $20 and GPT-6 Luna $2 at standard rates.
Which is cheaper with prompt caching, GPT-6.1 Terra or GPT-6 Luna?
GPT-6.1 Terra charges $0.05 per 1M cached input tokens, 95% below its standard input rate, and GPT-6 Luna $0.01, 90% below. With 9M of 10M input tokens cached and 2M output tokens, GPT-6.1 Terra costs $11.45 and GPT-6 Luna $1.19.
Which scores higher on independent benchmarks, GPT-6.1 Terra or GPT-6 Luna?
GPT-6.1 Terra leads on Arena WebDev, 1673 Elo to 1579 Elo; GPT-6.1 Terra leads on FrontierMath Tiers 1-3 (v2), 90.9% to 78.9%; GPT-6.1 Terra leads on GPQA Diamond, 94.3% to 90.5%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, GPT-6.1 Terra or GPT-6 Luna?
Both accept 1,050,000 tokens of context. Both return up to 128,000 tokens per response.
Further reading
More on GPT-6.1 Terra and GPT-6 Luna
Articles on GPT-6.1 Terra and GPT-6 Luna
- GPT-6.1 Terra: Price, Benchmarks and When to Use ItOctober 27, 2026
- OpenAI Models on Google Cloud: What Changes for AI TeamsOctober 22, 2026
- Claude Sonnet 5.5 vs GPT-6 Luna: Cost, Speed and AccuracySeptember 29, 2026
- GPT-6 Sol vs Claude Opus 5.5, Plus Luna: Best Value per TaskSeptember 24, 2026
- GPT-6 Sol and Luna: Half the Price, and Where Each One FitsSeptember 23, 2026
Related comparisons
- Claude Haiku 5.5 vs GPT-6.1 Terra
- Claude Haiku 5.5 vs GPT-6 Luna
- Claude Sonnet 5.5 vs GPT-6.1 Terra
- GPT-6 Luna vs Mistral Large 4
- Claude Sonnet 5 vs GPT-6.1 Terra
- GPT-6.1 Sol vs GPT-6 Luna
- DeepSeek-V4.1-Flash vs GPT-6.1 Terra
- Claude Sonnet 5.5 vs GPT-6 Luna
- Gemini 3.8 Flash vs GPT-6.1 Terra
- Claude Opus 5.5 vs GPT-6 Luna
- GPT-6.1 Sol vs GPT-6.1 Terra
- DeepSeek-V4.1-Flash vs GPT-6 Luna
Production evaluation
Choosing between GPT-6.1 Terra and GPT-6 Luna?
Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- A head-to-head evaluation on your real workload
- Routing between models by cost and difficulty