GPT-6.1 Terra vs GPT-6 Luna
GPT-6.1 Terra leads GPT-6 Luna on coding, 77.4 to 57.4 on the Vibe Coding Index, and GPT-6 Luna costs 10.0x less per output token ($0.50 vs $5.00 per million). Updated October 29, 2026; 33 benchmarks have a result for both.
GPT-6.1 Terra or GPT-6 Luna: which to pick
Pick GPT-6.1 Terra for coding: it scores 77.4 on the Vibe Coding Index against 57.4 for GPT-6 Luna, though on 4 benchmarks against 5.
Pick GPT-6 Luna for output tokens 10.0x cheaper ($0.50 vs $5.00 per million) and work measured by Tax Agent Bench (Vals AI) or Legal Research Bench (Vals AI), where it leads.
- Shared results
- 33
- GPT-6.1 Terra only
- 3
- GPT-6 Luna only
- 72
- Like-for-like categories
- 8 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
GPT-6.1 Terra
GPT-6.1 Terra scores 77.4 against 57.4.
4 and 5 benchmarks behind the scores
Intelligence
AA Intelligence Index
GPT-6.1 Terra
GPT-6.1 Terra leads, 51.0 against 27.8.
Same board, both measured
Web design
Design Arena: websites
GPT-6.1 Terra
GPT-6.1 Terra leads, 1283 against 1266.
Same board, both measured
General
Vals Index
GPT-6.1 Terra
GPT-6.1 Terra leads, 60.5% against 52.3%.
Same board, both measured
Long documents
Listed context window
No call
Both take 1.05M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-6 Luna
GPT-6.1 Terra $0.0035, GPT-6 Luna $0.0003 per turn.
List prices
At a glance
- Coding index
- GPT-6.1 Terra 77.4 from 4 benchmarks, GPT-6 Luna 57.4 from 5 benchmarks.
- Widest category
- Intelligence, 23.2 points apart on average over 1 shared benchmark.
- Widest single gap
- Mystery game puzzles: GPT-6.1 Terra 74.0% against GPT-6 Luna 7.0%, 67.0 points apart on a 0 to 100 scale.
- Output price
- GPT-6.1 Terra $5.00 against GPT-6 Luna $0.50 per million output tokens, 10.0x apart.
- Context window
- Both take 1.05M tokens.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | GPT-6.1 Terra | Bars | GPT-6 Luna | Ties |
|---|---|---|---|---|
| Coding | 8 | 0 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 4 | 3 | ||
| Reasoning | 4 | 0 | ||
| Math | 3 | 0 | ||
| Knowledge | 1 | 0 | ||
| Web design | 3 | 2 | ||
| General | 3 | 1 | ||
| All shared boards | 27 | 6 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index80
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| LiveBench coding | 94.3% | 84.5% | GPT-6.1 Terra |
| LMArena WebDev | 1673 | 1579 | GPT-6.1 Terra |
| Terminal-Bench 4 (Vals AI) | 49.5% | 13.6% | GPT-6.1 Terra |
| Vibe Code Bench (Vals AI) | 84.0% | 81.7% | GPT-6.1 Terra |
| Code migration (Vals AI) | Not measured | 42.5% | Only GPT-6 Luna measured |
| ProgramBench (Vals AI) | Not measured | 0.5% | Only GPT-6 Luna measured |
| IOI (Vals AI) | Not measured | 55.6% | Only GPT-6 Luna measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 73.0% | Only GPT-6 Luna measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 37.5% | Only GPT-6 Luna measured |
| CyberBench (Vals AI) | Not measured | 76.3% | Only GPT-6 Luna measured |
| SciCode | 55.1% | 54.6% | GPT-6.1 Terra |
| FrontierCode | Not measured | 42.4% | Only GPT-6 Luna measured |
| MirrorCode | Not measured | 26.7% | Only GPT-6 Luna measured |
| ALE-Bench | 2608.8 | 1576.9 | GPT-6.1 Terra |
| LMArena Text: coding | Not measured | 1437 | Only GPT-6 Luna measured |
| LMArena Text: software and IT | Not measured | 1425 | Only GPT-6 Luna measured |
| LMArena WebDev: React | 1657 | 1575 | GPT-6.1 Terra |
| LMArena WebDev: HTML | 1719 | 1595 | GPT-6.1 Terra |
| LMArena WebDev: from an image | Not measured | 1571 | Only GPT-6 Luna measured |
| Neither model has a result on the other 24 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| AA Intelligence Index | 51.0 | 27.8 | GPT-6.1 Terra |
| Epoch Capabilities Index | Not measured | 156.8 | Only GPT-6 Luna measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index43
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | Not measured | 1188 | Only GPT-6 Luna measured |
| Design Arena: agents building full-stack apps | Not measured | 1158 | Only GPT-6 Luna measured |
| Design Arena: agents building mobile apps | Not measured | 1134 | Only GPT-6 Luna measured |
| LiveBench research | 73.9% | 43.5% | GPT-6.1 Terra |
| LiveBench browser | 93.1% | 70.3% | GPT-6.1 Terra |
| LiveBench long agentic | 48.6% | 30.9% | GPT-6.1 Terra |
| SREBench (Vals AI) | Not measured | 2.7% | Only GPT-6 Luna measured |
| Finance Agent (Vals AI) | Not measured | 49.9% | Only GPT-6 Luna measured |
| Tax Agent Bench (Vals AI) | 15.2% | 19.9% | GPT-6 Luna |
| Legal Research Bench (Vals AI) | 26.0% | 30.3% | GPT-6 Luna |
| Harvey's Legal Agent Benchmark (Vals AI) | 1.7% | 4.2% | GPT-6 Luna |
| Excel Modeling Benchmark (Vals AI) | Not measured | 68.5% | Only GPT-6 Luna measured |
| BioMysteryBench (Vals AI) | Not measured | 61.5% | Only GPT-6 Luna measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 4.3% | Only GPT-6 Luna measured |
| Vals Science Index | Not measured | 28.4% | Only GPT-6 Luna measured |
| APEX-Agents | 68.3% | 44.3% | GPT-6.1 Terra |
| SpireClimb | Not measured | 0.0% | Only GPT-6 Luna measured |
| Neither model has a result on the other 25 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| LiveBench reasoning | 88.7% | 81.8% | GPT-6.1 Terra |
| MysteryMechanism (Vals AI) | Not measured | 19.4% | Only GPT-6 Luna measured |
| Humanity's Last Exam (Artificial Analysis run) | 46.2% | 38.5% | GPT-6.1 Terra |
| GPQA Diamond (Epoch AI run) | 94.3% | 90.5% | GPT-6.1 Terra |
| ARC-AGI | Not measured | 86.7% | Only GPT-6 Luna measured |
| ARC-AGI-2 | Not measured | 59.3% | Only GPT-6 Luna measured |
| Chess puzzles | Not measured | 36.0% | Only GPT-6 Luna measured |
| Mystery game puzzles | 74.0% | 7.0% | GPT-6.1 Terra |
| EBR-bench | 78.1% | Not measured | Only GPT-6.1 Terra measured |
| LMArena Text: hard prompts | Not measured | 1408 | Only GPT-6 Luna measured |
| LMArena Text: expert | Not measured | 1441 | Only GPT-6 Luna measured |
| LMArena Text: hard prompts in English | Not measured | 1410 | Only GPT-6 Luna measured |
| LMArena Vision: diagrams | Not measured | 1245 | Only GPT-6 Luna measured |
| LMArena Vision: homework | Not measured | 1261 | Only GPT-6 Luna measured |
| Humanity's Last Exam (Scale run) | 35.7% | Not measured | Only GPT-6.1 Terra measured |
| Neither model has a result on the other 8 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | 98.9% | GPT-6.1 Terra |
| FrontierMath, tiers 1 to 3 | 90.9% | 78.9% | GPT-6.1 Terra |
| FrontierMath, tier 4 | 92.7% | 56.1% | GPT-6.1 Terra |
| ProofBench | Not measured | 64.0% | Only GPT-6 Luna measured |
| LMArena Text: math | Not measured | 1410 | Only GPT-6 Luna measured |
| LMArena Text: mathematical work | Not measured | 1429 | Only GPT-6 Luna measured |
| Neither model has a result on the other 8 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| MedCode (Vals AI) | Not measured | 44.7% | Only GPT-6 Luna measured |
| SimpleQA Verified | 57.3% | 41.4% | GPT-6.1 Terra |
| LMArena Text: science | Not measured | 1387 | Only GPT-6 Luna measured |
| LMArena Text: medicine and healthcare | Not measured | 1355 | Only GPT-6 Luna measured |
| LMArena Text: legal and government | Not measured | 1396 | Only GPT-6 Luna measured |
| LMArena Text: business and finance | Not measured | 1384 | Only GPT-6 Luna measured |
| FACTS Benchmark Suite | Not measured | 62.3% | Only GPT-6 Luna measured |
| PRBench Legal | Not measured | 42.9% | Only GPT-6 Luna measured |
| Neither model has a result on the other 12 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index32
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| Design Arena: websites | 1283 | 1266 | GPT-6.1 Terra |
| Design Arena: UI components | 1277 | 1292 | GPT-6 Luna |
| Design Arena: game dev | 1348 | 1260 | GPT-6.1 Terra |
| Design Arena: data viz | Not measured | 1214 | Only GPT-6 Luna measured |
| Design Arena: 3D | Not measured | 1210 | Only GPT-6 Luna measured |
| Design Arena: all code categories | 1295 | 1265 | GPT-6.1 Terra |
| Design Arena: SVG | Not measured | 1246 | Only GPT-6 Luna measured |
| Design Arena: ASCII art | Not measured | 1147 | Only GPT-6 Luna measured |
| LiveBench design | 82.3% | 82.5% | GPT-6 Luna |
GeneralLike-for-likePublic boards, shown as published, kept out of the index31
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| Vals Index | 60.5% | 52.3% | GPT-6.1 Terra |
| LiveBench data analysis | 82.3% | 73.4% | GPT-6.1 Terra |
| Public Benefits Bench (Vals AI) | Not measured | 57.6% | Only GPT-6 Luna measured |
| SAGE (Vals AI) | Not measured | 83.4% | Only GPT-6 Luna measured |
| MedScribe (Vals AI) | Not measured | 83.7% | Only GPT-6 Luna measured |
| Long context reasoning (AA-LCR) | 82.7% | 83.3% | GPT-6 Luna |
| DTBench | Not measured | 90.1% | Only GPT-6 Luna measured |
| LMCA | Not measured | 44.5% | Only GPT-6 Luna measured |
| Furniture assembly | 79.2% | 44.2% | GPT-6.1 Terra |
| LMArena Text | Not measured | 1389 | Only GPT-6 Luna measured |
| LMArena Text: instruction following | Not measured | 1406 | Only GPT-6 Luna measured |
| LMArena Text: creative writing | Not measured | 1362 | Only GPT-6 Luna measured |
| LMArena Vision | Not measured | 1216 | Only GPT-6 Luna measured |
| LMArena Text: English | Not measured | 1394 | Only GPT-6 Luna measured |
| LMArena Text: non-English | Not measured | 1380 | Only GPT-6 Luna measured |
| LMArena Text: Chinese | Not measured | 1430 | Only GPT-6 Luna measured |
| LMArena Text: German | Not measured | 1378 | Only GPT-6 Luna measured |
| LMArena Text: Japanese | Not measured | 1368 | Only GPT-6 Luna measured |
| LMArena Text: Korean | Not measured | 1356 | Only GPT-6 Luna measured |
| LMArena Text: French | Not measured | 1406 | Only GPT-6 Luna measured |
| LMArena Text: Spanish | Not measured | 1391 | Only GPT-6 Luna measured |
| LMArena Text: Russian | Not measured | 1390 | Only GPT-6 Luna measured |
| LMArena Text: Polish | Not measured | 1380 | Only GPT-6 Luna measured |
| LMArena Text: multi-turn | Not measured | 1393 | Only GPT-6 Luna measured |
| LMArena Text: longer queries | Not measured | 1407 | Only GPT-6 Luna measured |
| LMArena Text: writing and language | Not measured | 1383 | Only GPT-6 Luna measured |
| LMArena Text: entertainment and media | Not measured | 1362 | Only GPT-6 Luna measured |
| LMArena Vision: English | Not measured | 1204 | Only GPT-6 Luna measured |
| LMArena Vision: Chinese | Not measured | 1266 | Only GPT-6 Luna measured |
| LMArena Vision: reading text | Not measured | 1225 | Only GPT-6 Luna measured |
| LMArena Vision: creative writing | Not measured | 1205 | Only GPT-6 Luna measured |
| MultiChallenge | 74.2% | Not measured | Only GPT-6.1 Terra measured |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-6.1 Terra | GPT-6 Luna | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
GPT-6 Luna costs less
Repository review
50K input + 3K output tokens
GPT-6 Luna costs less
Agent loop
200K input + 10K output tokens
GPT-6 Luna costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | OpenAI GPT-6.1 Terra | OpenAI GPT-6 Luna |
|---|---|---|
| Maker | OpenAI | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | October 26, 2026 | September 22, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $1.00 | $0.10 |
| Output $/Mtok | $5.00 | $0.50 |
| Coding index | 77.4 | 57.4 |
| Independent measurements behind it | 4 | 5 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-6.1 Terra better than GPT-6 Luna for coding?
Pick GPT-6.1 Terra for coding: it scores 77.4 on the Vibe Coding Index against 57.4 for GPT-6 Luna, though on 4 benchmarks against 5. Pick GPT-6 Luna for output tokens 10.0x cheaper ($0.50 vs $5.00 per million) and work measured by Tax Agent Bench (Vals AI) or Legal Research Bench (Vals AI), where it leads.
Which is cheaper, GPT-6.1 Terra or GPT-6 Luna?
GPT-6.1 Terra costs $1.00 per million input tokens and $5.00 per million output tokens; GPT-6 Luna costs $0.10 and $0.50. Cost per solved task is known for neither of them.
Which has the bigger context window, GPT-6.1 Terra or GPT-6 Luna?
Neither: both take 1.05M tokens.
How many benchmarks is the GPT-6.1 Terra vs GPT-6 Luna comparison based on?
33 benchmarks have a result for both models as of October 29, 2026. GPT-6.1 Terra's coding index rests on 4 independent benchmarks and GPT-6 Luna's on 5. Where only one model has a result, the page says so instead of naming a winner.