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Claude Opus 4.6 vs GPT-5.6 Terra

Updated October 21, 2026. 93 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Opus 4.6 Replace GPT-5.6 Terra
Claude Opus 4.6Anthropic
Coding
66.9
Overall
31.9
Output $/M
$25.00
66
GPT-5.6 TerraOpenAI
Coding
69.0
Overall
42.1
Output $/M
$12.00
27
vs boards won of 93 shared

Decision reading

Pick GPT-5.6 Terra for coding: it scores 69.0 on the Vibe Coding Index against 66.9 for Claude Opus 4.6.

Pick Claude Opus 4.6 when what matters is LMArena WebDev or LMArena Text: coding, where it leads.

Model AClaude Opus 4.6Anthropic66.9/1002 independent benchmarks$1.56 per solved taskModel BGPT-5.6 TerraOpenAI69.0/1002 independent benchmarks$0.42 per solved task
Shared results
93
Claude Opus 4.6 only
15
GPT-5.6 Terra only
31
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

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.

At a glance

Coding index
Claude Opus 4.6 66.9 from 2 benchmarks, GPT-5.6 Terra 69.0 from 2 benchmarks.
Widest category
Math, 18.3 points apart on average over 6 shared benchmarks.
Widest single gap
FrontierMath, tier 4: Claude Opus 4.6 26.8% against GPT-5.6 Terra 70.7%, 43.9 points apart on a 0 to 100 scale.
Output price
Claude Opus 4.6 $25.00 against GPT-5.6 Terra $12.00 per million output tokens, 2.1x apart.
Context window
Claude Opus 4.6 takes 1M tokens, GPT-5.6 Terra 1.05M.

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.

Boards won, where both have a result
CategoryClaude Opus 4.6BarsGPT-5.6 TerraTies
Coding66
Intelligence02
Agentic work71
Reasoning69
Math24
Knowledge101
Web design80
General274
All shared boards6627
CodingLike-for-likeFour of these boards feed the Vibe Coding Index66
Coding benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
SWE-bench Verified75.6%Not measuredOnly Claude Opus 4.6 measured
SWE-bench Multilingual72.0%Not measuredOnly Claude Opus 4.6 measured
LiveBench codingNot measured86.2%Only GPT-5.6 Terra measured
LMArena WebDev15471522Claude Opus 4.6
AA Coding IndexNot measured76.7Only GPT-5.6 Terra measured
LiveCodeBench (Vals AI)84.7%85.9%GPT-5.6 Terra
SWE-bench Verified (Vals AI)78.2%95.4%GPT-5.6 Terra
Terminal-Bench 4 (Vals AI)Not measured22.7%Only GPT-5.6 Terra measured
Vibe Code Bench (Vals AI)57.6%74.6%GPT-5.6 Terra
Code migration (Vals AI)Not measured47.8%Only GPT-5.6 Terra measured
ProgramBench (Vals AI)Not measured0.5%Only GPT-5.6 Terra measured
IOI (Vals AI)Not measured87.6%Only GPT-5.6 Terra measured
Terminal-Bench 2.1 (Vals AI)Not measured77.5%Only GPT-5.6 Terra measured
Vibe Code Bench 1-100 (Vals AI)Not measured14.8%Only GPT-5.6 Terra measured
SkillsBench (Vals AI)Not measured58.9%Only GPT-5.6 Terra measured
CyberBench (Vals AI)Not measured72.1%Only GPT-5.6 Terra measured
SciCodeNot measured55.0%Only GPT-5.6 Terra measured
Terminal-Bench Hard (Artificial Analysis run)48.5%62.9%GPT-5.6 Terra
Terminal-Bench79.8%Not measuredOnly Claude Opus 4.6 measured
FrontierCode26.6%41.3%GPT-5.6 Terra
GSO-Bench41.2%Not measuredOnly Claude Opus 4.6 measured
WeirdML78.0%78.3%GPT-5.6 Terra
Cybench93.0%Not measuredOnly Claude Opus 4.6 measured
ALE-BenchNot measured1951.4Only GPT-5.6 Terra measured
LMArena Text: coding15341485Claude Opus 4.6
LMArena Text: software and IT15271482Claude Opus 4.6
LMArena WebDev: React15391513Claude Opus 4.6
LMArena WebDev: HTML15591526Claude Opus 4.6
LMArena WebDev: from an image15431541Claude Opus 4.6
Neither model has a result on the other 9 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
AA Intelligence Index31.942.1GPT-5.6 Terra
Epoch Capabilities Index155.7160.1GPT-5.6 Terra
Agentic workLike-for-likePublic boards, shown as published, kept out of the index71
Agentic work benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
AA Agentic IndexNot measured43.2Only GPT-5.6 Terra measured
Design Arena: agents building web apps12061120Claude Opus 4.6
Design Arena: agents building full-stack apps12201061Claude Opus 4.6
Design Arena: agents building mobile apps12071112Claude Opus 4.6
Design Arena: agents building Android apps12041066Claude Opus 4.6
Design Arena: agents building games12141082Claude Opus 4.6
Design Arena: HTML slidesNot measured1108Only GPT-5.6 Terra measured
Design Arena: PowerPoint slidesNot measured1130Only GPT-5.6 Terra measured
LiveBench researchNot measured60.4%Only GPT-5.6 Terra measured
LiveBench browserNot measured84.0%Only GPT-5.6 Terra measured
LiveBench long agenticNot measured48.4%Only GPT-5.6 Terra measured
SREBench (Vals AI)Not measured9.5%Only GPT-5.6 Terra measured
Finance Agent (Vals AI)Not measured54.4%Only GPT-5.6 Terra measured
Tax Agent Bench (Vals AI)Not measured30.0%Only GPT-5.6 Terra measured
Legal Research Bench (Vals AI)Not measured41.4%Only GPT-5.6 Terra measured
Excel Modeling Benchmark (Vals AI)Not measured66.2%Only GPT-5.6 Terra measured
Terminal-Bench-Science (Vals AI)Not measured10.0%Only GPT-5.6 Terra measured
τ²-Bench Telecom92.1%86.3%Claude Opus 4.6
APEX-Agents46.3%58.2%GPT-5.6 Terra
METR time horizons78.9%Not measuredOnly Claude Opus 4.6 measured
Remote Labor Index4.2%Not measuredOnly Claude Opus 4.6 measured
BALROGNot measured53.2%Only GPT-5.6 Terra measured
DeepResearch Bench55.3%Not measuredOnly Claude Opus 4.6 measured
Vending-Bench 2$8,018$7,343Claude Opus 4.6
Neither model has a result on the other 15 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index69
Reasoning benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
GPQA Diamond89.7%90.9%GPT-5.6 Terra
LiveBench reasoningNot measured90.6%Only GPT-5.6 Terra measured
MMMU Pro (Vals AI)83.9%86.5%GPT-5.6 Terra
GPQA Diamond (Artificial Analysis run)89.6%92.5%GPT-5.6 Terra
Humanity's Last Exam (Artificial Analysis run)39.9%42.9%GPT-5.6 Terra
GPQA Diamond (Epoch AI run)90.5%93.3%GPT-5.6 Terra
ARC-AGI94.0%96.5%GPT-5.6 Terra
ARC-AGI-269.2%83.9%GPT-5.6 Terra
SimpleBench67.6%48.9%Claude Opus 4.6
Chess puzzles21.0%47.0%GPT-5.6 Terra
Mystery game puzzles25.0%35.0%GPT-5.6 Terra
EBR-bench12.7%Not measuredOnly Claude Opus 4.6 measured
LMArena Text: hard prompts15251469Claude Opus 4.6
LMArena Text: expert15441496Claude Opus 4.6
LMArena Text: hard prompts in English15301465Claude Opus 4.6
LMArena Vision: diagrams13401295Claude Opus 4.6
LMArena Vision: homework13371312Claude Opus 4.6
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index24
Math benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
AIME95.6%Not measuredOnly Claude Opus 4.6 measured
OTIS Mock AIME94.4%99.7%GPT-5.6 Terra
FrontierMath, tiers 1 to 366.0%86.0%GPT-5.6 Terra
FrontierMath, tier 426.8%70.7%GPT-5.6 Terra
ProofBench50.0%74.0%GPT-5.6 Terra
LMArena Text: math15181465Claude Opus 4.6
LMArena Text: mathematical work15251478Claude Opus 4.6
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index101
Knowledge benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
MMLU Pro89.1%86.7%Claude Opus 4.6
LegalBench (Vals AI)85.3%85.1%Claude Opus 4.6
CaseLaw (Vals AI)62.1%Not measuredOnly Claude Opus 4.6 measured
CorpFin (Vals AI)67.0%65.3%Claude Opus 4.6
TaxEval (Vals AI)76.0%76.2%GPT-5.6 Terra
MortgageTax (Vals AI)68.5%67.3%Claude Opus 4.6
MedQA (Vals AI)95.4%Not measuredOnly Claude Opus 4.6 measured
MedCode (Vals AI)49.1%43.4%Claude Opus 4.6
SimpleQA Verified47.0%43.2%Claude Opus 4.6
LMArena Text: science15191452Claude Opus 4.6
LMArena Text: medicine and healthcare15041430Claude Opus 4.6
LMArena Text: legal and government15121461Claude Opus 4.6
LMArena Text: business and finance14971448Claude Opus 4.6
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index80
Web design benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
Design Arena: websites12911269Claude Opus 4.6
Design Arena: UI components12841259Claude Opus 4.6
Design Arena: game dev12781230Claude Opus 4.6
Design Arena: data viz12791240Claude Opus 4.6
Design Arena: 3D12741135Claude Opus 4.6
Design Arena: all code categories12891241Claude Opus 4.6
Design Arena: SVG12271220Claude Opus 4.6
Design Arena: ASCII art12541177Claude Opus 4.6
LiveBench designNot measured76.0%Only GPT-5.6 Terra measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index274
General benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
LiveBench data analysisNot measured79.3%Only GPT-5.6 Terra measured
Public Benefits Bench (Vals AI)Not measured62.4%Only GPT-5.6 Terra measured
SAGE (Vals AI)51.6%47.0%Claude Opus 4.6
MedScribe (Vals AI)86.7%82.9%Claude Opus 4.6
Vals Multimodal IndexNot measured65.1%Only GPT-5.6 Terra measured
IFBench53.1%71.2%GPT-5.6 Terra
Long context reasoning (AA-LCR)78.0%83.0%GPT-5.6 Terra
DTBench91.2%93.3%GPT-5.6 Terra
LMCA55.8%54.9%Claude Opus 4.6
CL-bench20.7%Not measuredOnly Claude Opus 4.6 measured
Surface Evolver BenchNot measured83.8%Only GPT-5.6 Terra measured
Furniture assembly28.3%54.2%GPT-5.6 Terra
CL-bench Life17.0%Not measuredOnly Claude Opus 4.6 measured
LMArena Text15011448Claude Opus 4.6
LMArena Text: instruction following15211456Claude Opus 4.6
LMArena Text: creative writing15051413Claude Opus 4.6
LMArena Vision13161271Claude Opus 4.6
LMArena Text: English15111449Claude Opus 4.6
LMArena Text: non-English14881441Claude Opus 4.6
LMArena Text: Chinese15511514Claude Opus 4.6
LMArena Text: German15001460Claude Opus 4.6
LMArena Text: Japanese14881454Claude Opus 4.6
LMArena Text: Korean14641427Claude Opus 4.6
LMArena Text: French15121466Claude Opus 4.6
LMArena Text: Spanish15101451Claude Opus 4.6
LMArena Text: Russian14971452Claude Opus 4.6
LMArena Text: Polish14991446Claude Opus 4.6
LMArena Text: multi-turn15111453Claude Opus 4.6
LMArena Text: longer queries15181454Claude Opus 4.6
LMArena Text: writing and language15021431Claude Opus 4.6
LMArena Text: entertainment and media14921418Claude Opus 4.6
LMArena Vision: English13241272Claude Opus 4.6
LMArena Vision: Chinese13701337Claude Opus 4.6
LMArena Vision: reading text13261278Claude Opus 4.6
LMArena Vision: humor13141236Claude Opus 4.6
LMArena Vision: recognizing things1274Not measuredOnly Claude Opus 4.6 measured
LMArena Vision: creative writing13311248Claude Opus 4.6
LMArena Document15071472Claude Opus 4.6
Neither model has a result on the other 8 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Opus 4.6 and GPT-5.6 Terra
BenchmarkClaude Opus 4.6GPT-5.6 TerraLeader
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

Claude Opus 4.6$0.018Fits in one request
GPT-5.6 Terra$0.0080Fits in one request

GPT-5.6 Terra costs less

Repository review

50K input + 3K output tokens

Claude Opus 4.6$0.325Fits in one request
GPT-5.6 Terra$0.136Fits in one request

GPT-5.6 Terra costs less

Agent loop

200K input + 10K output tokens

Claude Opus 4.6$1.25Fits in one request
GPT-5.6 Terra$0.520Fits in one request

GPT-5.6 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.

Specifications of Claude Opus 4.6 and GPT-5.6 Terra
SpecificationAnthropic Claude Opus 4.6OpenAI GPT-5.6 Terra
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedFebruary 4, 2026July 9, 2026
Context window1M1.05M
Input $/Mtok$5.00$2.00
Output $/Mtok$25.00$12.00
Coding index66.969.0
Independent measurements behind it22
Cost per solved task$1.56$0.42
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 4.6 better than GPT-5.6 Terra for coding?

Pick GPT-5.6 Terra for coding: it scores 69.0 on the Vibe Coding Index against 66.9 for Claude Opus 4.6. Pick Claude Opus 4.6 when what matters is LMArena WebDev or LMArena Text: coding, where it leads.

Which is cheaper, Claude Opus 4.6 or GPT-5.6 Terra?

Claude Opus 4.6 costs $5.00 per million input tokens and $25.00 per million output tokens; GPT-5.6 Terra costs $2.00 and $12.00. Per solved SWE-bench Verified task, Claude Opus 4.6 costs $1.56 and GPT-5.6 Terra $0.42.

Which has the bigger context window, Claude Opus 4.6 or GPT-5.6 Terra?

GPT-5.6 Terra, with 1.05M tokens against 1M.

How many benchmarks is the Claude Opus 4.6 vs GPT-5.6 Terra comparison based on?

93 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.6's coding index rests on 2 independent benchmarks and GPT-5.6 Terra's on 2. Where only one model has a result, the page says so instead of naming a winner.

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