GPT-5.6 Terra vs GPT-6.1 Terra
GPT-6.1 Terra leads GPT-5.6 Terra on coding, 77.4 to 63.8 on the Vibe Coding Index, and GPT-6.1 Terra costs 2.4x less per output token ($5.00 vs $12.00 per million). Updated October 29, 2026; 30 benchmarks have a result for both.
vs boards won of 30 shared
GPT-5.6 Terra or GPT-6.1 Terra: which to pick
Pick GPT-6.1 Terra for coding: it scores 77.4 on the Vibe Coding Index against 63.8 for GPT-5.6 Terra, though on 4 benchmarks against 6.
Pick GPT-5.6 Terra for work measured by Tax Agent Bench (Vals AI) or Legal Research Bench (Vals AI), where it leads.
Model AGPT-5.6 TerraOpenAI63.8/1006 independent benchmarks$0.42 per solved taskModel BGPT-6.1 TerraOpenAI77.4/1004 independent benchmarksNo cost per solved task
- Shared results
- 30
- GPT-5.6 Terra only
- 99
- GPT-6.1 Terra only
- 6
- Like-for-like categories
- 7 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 63.8.
6 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
No call
Only GPT-6.1 Terra has a AA Intelligence Index result, 51.0.
Directional only
Agentic work
AA Agentic Index
No call
Only GPT-5.6 Terra has a AA Agentic Index result, 43.2.
Directional only
Reasoning
GPQA Diamond
No call
Only GPT-5.6 Terra has a GPQA Diamond result, 90.9%.
Directional only
Knowledge
MMLU Pro
No call
Only GPT-5.6 Terra has a MMLU Pro result, 86.7%.
Directional only
Web design
Design Arena: websites
GPT-6.1 Terra
GPT-6.1 Terra leads, 1283 against 1267.
Same board, both measured
General
Vals Index
No call
Only GPT-6.1 Terra has a Vals Index result, 60.5%.
Directional only
Long documents
Listed context window
No call
Both take 1.05M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-6.1 Terra
GPT-5.6 Terra $0.0080, GPT-6.1 Terra $0.0035 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5.6 Terra has the number, $0.42.
Directional only
At a glance
- Coding index
- GPT-5.6 Terra 63.8 from 6 benchmarks, GPT-6.1 Terra 77.4 from 4 benchmarks.
- Widest category
- Coding, 15.6 points apart on average over 8 shared benchmarks.
- Widest single gap
- Mystery game puzzles: GPT-5.6 Terra 35.0% against GPT-6.1 Terra 74.0%, 39.0 points apart on a 0 to 100 scale.
- Output price
- GPT-5.6 Terra $12.00 against GPT-6.1 Terra $5.00 per million output tokens, 2.4x 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-5.6 Terra | Bars | GPT-6.1 Terra | Ties |
|---|---|---|---|---|
| Coding | 0 | 8 | ||
| Agentic work | 2 | 4 | ||
| Reasoning | 1 | 3 | ||
| Math | 0 | 3 | ||
| Knowledge | 0 | 1 | ||
| Web design | 0 | 5 | ||
| General | 1 | 2 | ||
| All shared boards | 4 | 26 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index08
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | Leader |
|---|---|---|---|
| LiveBench coding | 86.2% | 94.3% | GPT-6.1 Terra |
| LMArena WebDev | 1520 | 1673 | GPT-6.1 Terra |
| AA Coding Index | 76.7 | Not measured | Only GPT-5.6 Terra measured |
| LiveCodeBench (Vals AI) | 85.9% | Not measured | Only GPT-5.6 Terra measured |
| SWE-bench Verified (Vals AI) | 95.4% | Not measured | Only GPT-5.6 Terra measured |
| Terminal-Bench 4 (Vals AI) | 22.7% | 49.5% | GPT-6.1 Terra |
| Vibe Code Bench (Vals AI) | 74.6% | 84.0% | GPT-6.1 Terra |
| Code migration (Vals AI) | 47.8% | Not measured | Only GPT-5.6 Terra measured |
| ProgramBench (Vals AI) | 0.5% | Not measured | Only GPT-5.6 Terra measured |
| IOI (Vals AI) | 87.6% | Not measured | Only GPT-5.6 Terra measured |
| Terminal-Bench 2.1 (Vals AI) | 77.5% | Not measured | Only GPT-5.6 Terra measured |
| Vibe Code Bench 1-100 (Vals AI) | 14.8% | Not measured | Only GPT-5.6 Terra measured |
| SkillsBench (Vals AI) | 58.9% | Not measured | Only GPT-5.6 Terra measured |
| CyberBench (Vals AI) | 72.1% | Not measured | Only GPT-5.6 Terra measured |
| SciCode | 55.0% | 55.1% | GPT-6.1 Terra |
| Terminal-Bench Hard (Artificial Analysis run) | 62.9% | Not measured | Only GPT-5.6 Terra measured |
| FrontierCode | 41.3% | Not measured | Only GPT-5.6 Terra measured |
| WeirdML | 78.3% | Not measured | Only GPT-5.6 Terra measured |
| ALE-Bench | 1951.4 | 2608.8 | GPT-6.1 Terra |
| LMArena Text: coding | 1485 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: software and IT | 1482 | Not measured | Only GPT-5.6 Terra measured |
| LMArena WebDev: React | 1510 | 1657 | GPT-6.1 Terra |
| LMArena WebDev: HTML | 1524 | 1719 | GPT-6.1 Terra |
| LMArena WebDev: from an image | 1541 | Not measured | Only GPT-5.6 Terra measured |
| SciCode | 10.8% | Not measured | Only GPT-5.6 Terra measured |
| SWE-Bench Pro V2 | 92.4% | Not measured | Only GPT-5.6 Terra measured |
| Neither model has a result on the other 17 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 51.0 | Only GPT-6.1 Terra measured |
| Epoch Capabilities Index | 160.1 | Not measured | Only GPT-5.6 Terra measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index24
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | Leader |
|---|---|---|---|
| AA Agentic Index | 43.2 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: agents building web apps | 1121 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: agents building full-stack apps | 1061 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: agents building mobile apps | 1103 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: agents building Android apps | 1057 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: agents building games | 1047 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: HTML slides | 1004 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: PowerPoint slides | 1083 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: spreadsheets | 1081 | Not measured | Only GPT-5.6 Terra measured |
| LiveBench research | 60.4% | 73.9% | GPT-6.1 Terra |
| LiveBench browser | 70.3% | 93.1% | GPT-6.1 Terra |
| LiveBench long agentic | 33.1% | 48.6% | GPT-6.1 Terra |
| SREBench (Vals AI) | 9.5% | Not measured | Only GPT-5.6 Terra measured |
| Finance Agent (Vals AI) | 54.4% | Not measured | Only GPT-5.6 Terra measured |
| Tax Agent Bench (Vals AI) | 30.0% | 15.2% | GPT-5.6 Terra |
| Legal Research Bench (Vals AI) | 41.4% | 26.0% | GPT-5.6 Terra |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 1.7% | Only GPT-6.1 Terra measured |
| Excel Modeling Benchmark (Vals AI) | 66.2% | Not measured | Only GPT-5.6 Terra measured |
| Terminal-Bench-Science (Vals AI) | 10.0% | Not measured | Only GPT-5.6 Terra measured |
| τ²-Bench Telecom | 86.3% | Not measured | Only GPT-5.6 Terra measured |
| APEX-Agents | 58.2% | 68.3% | GPT-6.1 Terra |
| BALROG | 53.2% | Not measured | Only GPT-5.6 Terra measured |
| Vending-Bench 2 | $7,343 | Not measured | Only GPT-5.6 Terra measured |
| Neither model has a result on the other 19 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index13
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | Leader |
|---|---|---|---|
| GPQA Diamond | 90.9% | Not measured | Only GPT-5.6 Terra measured |
| LiveBench reasoning | 90.6% | 88.7% | GPT-5.6 Terra |
| MMMU Pro (Vals AI) | 86.5% | Not measured | Only GPT-5.6 Terra measured |
| GPQA Diamond (Artificial Analysis run) | 92.5% | Not measured | Only GPT-5.6 Terra measured |
| Humanity's Last Exam (Artificial Analysis run) | 42.9% | 46.2% | GPT-6.1 Terra |
| GPQA Diamond (Epoch AI run) | 93.3% | 94.3% | GPT-6.1 Terra |
| ARC-AGI | 96.5% | Not measured | Only GPT-5.6 Terra measured |
| ARC-AGI-2 | 83.9% | Not measured | Only GPT-5.6 Terra measured |
| SimpleBench | 48.9% | Not measured | Only GPT-5.6 Terra measured |
| Chess puzzles | 47.0% | Not measured | Only GPT-5.6 Terra measured |
| Mystery game puzzles | 35.0% | 74.0% | GPT-6.1 Terra |
| EBR-bench | Not measured | 78.1% | Only GPT-6.1 Terra measured |
| LMArena Text: hard prompts | 1469 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: expert | 1495 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: hard prompts in English | 1465 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Vision: diagrams | 1295 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Vision: homework | 1312 | Not measured | Only GPT-5.6 Terra measured |
| Kagi LLM Benchmark | 51.3% | Not measured | Only GPT-5.6 Terra measured |
| Humanity's Last Exam (Scale run) | Not measured | 35.7% | Only GPT-6.1 Terra measured |
| Neither model has a result on the other 4 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | Leader |
|---|---|---|---|
| OTIS Mock AIME | 99.7% | 100.0% | GPT-6.1 Terra |
| FrontierMath, tiers 1 to 3 | 86.0% | 90.9% | GPT-6.1 Terra |
| FrontierMath, tier 4 | 70.7% | 92.7% | GPT-6.1 Terra |
| ProofBench | 74.0% | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: math | 1464 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: mathematical work | 1477 | Not measured | Only GPT-5.6 Terra measured |
| Neither model has a result on the other 8 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | Leader |
|---|---|---|---|
| MMLU Pro | 86.7% | Not measured | Only GPT-5.6 Terra measured |
| LegalBench (Vals AI) | 85.1% | Not measured | Only GPT-5.6 Terra measured |
| CorpFin (Vals AI) | 65.3% | Not measured | Only GPT-5.6 Terra measured |
| TaxEval (Vals AI) | 76.2% | Not measured | Only GPT-5.6 Terra measured |
| MortgageTax (Vals AI) | 67.3% | Not measured | Only GPT-5.6 Terra measured |
| MedCode (Vals AI) | 43.4% | Not measured | Only GPT-5.6 Terra measured |
| SimpleQA Verified | 43.2% | 57.3% | GPT-6.1 Terra |
| LMArena Text: science | 1453 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: medicine and healthcare | 1432 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: legal and government | 1461 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: business and finance | 1447 | Not measured | Only GPT-5.6 Terra measured |
| FACTS Benchmark Suite | 50.0% | Not measured | Only GPT-5.6 Terra measured |
| Neither model has a result on the other 8 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | Leader |
|---|---|---|---|
| Design Arena: websites | 1267 | 1283 | GPT-6.1 Terra |
| Design Arena: UI components | 1254 | 1277 | GPT-6.1 Terra |
| Design Arena: game dev | 1229 | 1348 | GPT-6.1 Terra |
| Design Arena: data viz | 1240 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: 3D | 1131 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: all code categories | 1240 | 1295 | GPT-6.1 Terra |
| Design Arena: SVG | 1217 | Not measured | Only GPT-5.6 Terra measured |
| Design Arena: ASCII art | 1176 | Not measured | Only GPT-5.6 Terra measured |
| LiveBench design | 76.0% | 82.3% | GPT-6.1 Terra |
GeneralLike-for-likePublic boards, shown as published, kept out of the index12
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | Leader |
|---|---|---|---|
| Vals Index | Not measured | 60.5% | Only GPT-6.1 Terra measured |
| LiveBench data analysis | 79.3% | 82.3% | GPT-6.1 Terra |
| Public Benefits Bench (Vals AI) | 62.4% | Not measured | Only GPT-5.6 Terra measured |
| SAGE (Vals AI) | 87.0% | Not measured | Only GPT-5.6 Terra measured |
| MedScribe (Vals AI) | 82.9% | Not measured | Only GPT-5.6 Terra measured |
| Vals Multimodal Index | 65.1% | Not measured | Only GPT-5.6 Terra measured |
| IFBench | 71.2% | Not measured | Only GPT-5.6 Terra measured |
| Long context reasoning (AA-LCR) | 83.0% | 82.7% | GPT-5.6 Terra |
| DTBench | 93.3% | Not measured | Only GPT-5.6 Terra measured |
| LMCA | 54.9% | Not measured | Only GPT-5.6 Terra measured |
| Surface Evolver Bench | 83.8% | Not measured | Only GPT-5.6 Terra measured |
| Furniture assembly | 54.2% | 79.2% | GPT-6.1 Terra |
| LMArena Text | 1448 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: instruction following | 1455 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: creative writing | 1413 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Vision | 1271 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: English | 1449 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: non-English | 1441 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: Chinese | 1514 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: German | 1460 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: Japanese | 1445 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: Korean | 1426 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: French | 1468 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: Spanish | 1448 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: Russian | 1453 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: Polish | 1449 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: multi-turn | 1455 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: longer queries | 1453 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: writing and language | 1432 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Text: entertainment and media | 1419 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Vision: English | 1272 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Vision: Chinese | 1337 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Vision: reading text | 1278 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Vision: humor | 1236 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Vision: creative writing | 1248 | Not measured | Only GPT-5.6 Terra measured |
| LMArena Document | 1472 | Not measured | Only GPT-5.6 Terra measured |
| MultiChallenge | Not measured | 74.2% | Only GPT-6.1 Terra measured |
| EQ-Bench 4 | 1220 | Not measured | Only GPT-5.6 Terra measured |
| Neither model has a result on the other 10 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-5.6 Terra | GPT-6.1 Terra | 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-5.6 Terra$0.0080Fits in one request
GPT-6.1 Terra$0.0035Fits in one request
GPT-6.1 Terra costs less
Repository review
50K input + 3K output tokens
GPT-5.6 Terra$0.136Fits in one request
GPT-6.1 Terra$0.065Fits in one request
GPT-6.1 Terra costs less
Agent loop
200K input + 10K output tokens
GPT-5.6 Terra$0.520Fits in one request
GPT-6.1 Terra$0.250Fits in one request
GPT-6.1 Terra 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-5.6 Terra | OpenAI GPT-6.1 Terra |
|---|---|---|
| Maker | OpenAI | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | July 9, 2026 | October 26, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $2.00 | $1.00 |
| Output $/Mtok | $12.00 | $5.00 |
| Coding index | 63.8 | 77.4 |
| Independent measurements behind it | 6 | 4 |
| Cost per solved task | $0.42 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-5.6 Terra better than GPT-6.1 Terra for coding?
Pick GPT-6.1 Terra for coding: it scores 77.4 on the Vibe Coding Index against 63.8 for GPT-5.6 Terra, though on 4 benchmarks against 6. Pick GPT-5.6 Terra for work measured by Tax Agent Bench (Vals AI) or Legal Research Bench (Vals AI), where it leads.
Which is cheaper, GPT-5.6 Terra or GPT-6.1 Terra?
GPT-5.6 Terra costs $2.00 per million input tokens and $12.00 per million output tokens; GPT-6.1 Terra costs $1.00 and $5.00. Cost per solved task is known for GPT-5.6 Terra only.
Which has the bigger context window, GPT-5.6 Terra or GPT-6.1 Terra?
Neither: both take 1.05M tokens.
How many benchmarks is the GPT-5.6 Terra vs GPT-6.1 Terra comparison based on?
30 benchmarks have a result for both models as of October 29, 2026. GPT-5.6 Terra's coding index rests on 6 independent benchmarks and GPT-6.1 Terra's on 4. Where only one model has a result, the page says so instead of naming a winner.