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Claude Sonnet 4.6 vs GPT-5.6 Terra

GPT-5.6 Terra leads Claude Sonnet 4.6 on coding, 63.9 to 57.3 on the Vibe Coding Index, and GPT-5.6 Terra costs 1.3x less per output token ($12.00 vs $15.00 per million). Updated October 22, 2026; 109 benchmarks have a result for both.

Replace Claude Sonnet 4.6 Replace GPT-5.6 Terra
Claude Sonnet 4.6Anthropic
Coding
57.3
Overall
60.3
Output $/M
$15.00
45
GPT-5.6 TerraOpenAI
Coding
63.9
Overall
68.1
Output $/M
$12.00
62
vs boards won of 109 shared, 2 tied

Claude Sonnet 4.6 or GPT-5.6 Terra: which to pick

Pick GPT-5.6 Terra for coding: it scores 63.9 on the Vibe Coding Index against 57.3 for Claude Sonnet 4.6.

Pick Claude Sonnet 4.6 for work measured by LMArena WebDev or LMArena Text: coding, where it leads.

Model AClaude Sonnet 4.6Anthropic57.3/1005 independent benchmarks$1.68 per solved taskModel BGPT-5.6 TerraOpenAI63.9/1006 independent benchmarks$0.42 per solved task
Shared results
109
Claude Sonnet 4.6 only
14
GPT-5.6 Terra only
20
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.

At a glance

Coding index
Claude Sonnet 4.6 57.3 from 5 benchmarks, GPT-5.6 Terra 63.9 from 6 benchmarks.
Widest category
Math, 11.0 points apart on average over 4 shared benchmarks.
Widest single gap
ProofBench: Claude Sonnet 4.6 45.0% against GPT-5.6 Terra 74.0%, 29.0 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 4.6 $15.00 against GPT-5.6 Terra $12.00 per million output tokens, 1.3x apart.
Context window
Claude Sonnet 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 Sonnet 4.6BarsGPT-5.6 TerraTies
Coding4141 tie
Intelligence02
Agentic work610
Reasoning411
Math13
Knowledge731 tie
Web design72
General1617
All shared boards45622 ties
CodingLike-for-likeSix of these boards feed the Vibe Coding Index414
Coding benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.6GPT-5.6 TerraLeader
LiveBench coding66.6%86.2%GPT-5.6 Terra
LMArena WebDev15231522Claude Sonnet 4.6
AA Coding Index63.076.7GPT-5.6 Terra
LiveCodeBench (Vals AI)82.1%85.9%GPT-5.6 Terra
SWE-bench Verified (Vals AI)77.4%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)55.8%74.6%GPT-5.6 Terra
Code migration (Vals AI)39.9%47.8%GPT-5.6 Terra
ProgramBench (Vals AI)0.5%0.5%Tie
IOI (Vals AI)Not measured87.6%Only GPT-5.6 Terra measured
Terminal-Bench 2.1 (Vals AI)57.3%77.5%GPT-5.6 Terra
Vibe Code Bench 1-100 (Vals AI)Not measured14.8%Only GPT-5.6 Terra measured
SkillsBench (Vals AI)49.0%58.9%GPT-5.6 Terra
CyberBench (Vals AI)Not measured72.1%Only GPT-5.6 Terra measured
SciCode50.1%55.0%GPT-5.6 Terra
Terminal-Bench Hard (Artificial Analysis run)53.0%62.9%GPT-5.6 Terra
Terminal-Bench53.4%Not measuredOnly Claude Sonnet 4.6 measured
FrontierCode24.3%41.3%GPT-5.6 Terra
WeirdML66.1%78.3%GPT-5.6 Terra
ALE-BenchNot measured1951.4Only GPT-5.6 Terra measured
LMArena Text: coding15031485Claude Sonnet 4.6
LMArena Text: software and IT14911482Claude Sonnet 4.6
LMArena WebDev: React15121513GPT-5.6 Terra
LMArena WebDev: HTML15271526Claude Sonnet 4.6
LMArena WebDev: from an image15291541GPT-5.6 Terra
SciCodeNot measured10.8%Only GPT-5.6 Terra measured
SWE-Bench Pro V2Not measured92.4%Only GPT-5.6 Terra measured
SWE Atlas: Codebase QnA31.2%Not measuredOnly Claude Sonnet 4.6 measured
SWE Atlas: Refactoring32.2%Not measuredOnly Claude Sonnet 4.6 measured
SWE Atlas: Test Writing31.8%Not measuredOnly Claude Sonnet 4.6 measured
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.6GPT-5.6 TerraLeader
AA Intelligence Index30.142.1GPT-5.6 Terra
Epoch Capabilities Index152.8160.1GPT-5.6 Terra
Agentic workLike-for-likePublic boards, shown as published, kept out of the index610
Agentic work benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.6GPT-5.6 TerraLeader
AA Agentic Index31.843.2GPT-5.6 Terra
Design Arena: agents building web apps11901120Claude Sonnet 4.6
Design Arena: agents building full-stack apps12131061Claude Sonnet 4.6
Design Arena: agents building mobile apps12111110Claude Sonnet 4.6
Design Arena: agents building Android apps11961060Claude Sonnet 4.6
Design Arena: agents building Godot games1226Not measuredOnly Claude Sonnet 4.6 measured
Design Arena: agents building games11771083Claude Sonnet 4.6
Design Arena: HTML slidesNot measured1047Only GPT-5.6 Terra measured
Design Arena: PowerPoint slidesNot measured1104Only GPT-5.6 Terra measured
LiveBench research63.6%60.4%Claude Sonnet 4.6
LiveBench browser68.0%84.0%GPT-5.6 Terra
LiveBench long agentic23.1%48.4%GPT-5.6 Terra
SREBench (Vals AI)Not measured9.5%Only GPT-5.6 Terra measured
Finance Agent (Vals AI)51.0%54.4%GPT-5.6 Terra
Tax Agent Bench (Vals AI)25.8%30.0%GPT-5.6 Terra
Legal Research Bench (Vals AI)38.5%41.4%GPT-5.6 Terra
Excel Modeling Benchmark (Vals AI)60.2%66.2%GPT-5.6 Terra
Terminal-Bench-Science (Vals AI)Not measured10.0%Only GPT-5.6 Terra measured
τ²-Bench Telecom79.5%86.3%GPT-5.6 Terra
APEX-Agents43.0%58.2%GPT-5.6 Terra
OSWorld 2.09.3%Not measuredOnly Claude Sonnet 4.6 measured
BALROGNot measured53.2%Only GPT-5.6 Terra measured
DeepResearch Bench54.9%Not measuredOnly Claude Sonnet 4.6 measured
OSWorld72.1%Not measuredOnly Claude Sonnet 4.6 measured
Vending-Bench 2$7,204$7,343GPT-5.6 Terra
MCP Atlas69.5%Not measuredOnly Claude Sonnet 4.6 measured
Neither model has a result on the other 16 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index411
Reasoning benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.6GPT-5.6 TerraLeader
GPQA Diamond85.6%90.9%GPT-5.6 Terra
LiveBench reasoning86.4%90.6%GPT-5.6 Terra
MMMU Pro (Vals AI)83.6%86.5%GPT-5.6 Terra
GPQA Diamond (Artificial Analysis run)87.5%92.5%GPT-5.6 Terra
Humanity's Last Exam (Artificial Analysis run)33.6%42.9%GPT-5.6 Terra
GPQA Diamond (Epoch AI run)87.4%93.3%GPT-5.6 Terra
ARC-AGI86.5%96.5%GPT-5.6 Terra
ARC-AGI-260.4%83.9%GPT-5.6 Terra
SimpleBenchNot measured48.9%Only GPT-5.6 Terra measured
Chess puzzles23.0%47.0%GPT-5.6 Terra
Mystery game puzzles16.0%35.0%GPT-5.6 Terra
LMArena Text: hard prompts14851469Claude Sonnet 4.6
LMArena Text: expert15001496Claude Sonnet 4.6
LMArena Text: hard prompts in English14931465Claude Sonnet 4.6
LMArena Vision: diagrams13061295Claude Sonnet 4.6
LMArena Vision: homework13111312GPT-5.6 Terra
Kagi LLM BenchmarkNot measured51.3%Only GPT-5.6 Terra measured
Neither model has a result on the other 6 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index13
Math benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.6GPT-5.6 TerraLeader
AIME92.3%Not measuredOnly Claude Sonnet 4.6 measured
OTIS Mock AIME85.8%99.7%GPT-5.6 Terra
FrontierMath, tiers 1 to 3Not measured86.0%Only GPT-5.6 Terra measured
FrontierMath, tier 4Not measured70.7%Only GPT-5.6 Terra measured
ProofBench45.0%74.0%GPT-5.6 Terra
LMArena Text: math14621465GPT-5.6 Terra
LMArena Text: mathematical work14831478Claude Sonnet 4.6
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index73
Knowledge benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.6GPT-5.6 TerraLeader
MMLU Pro87.3%86.7%Claude Sonnet 4.6
LegalBench (Vals AI)82.1%85.1%GPT-5.6 Terra
CaseLaw (Vals AI)64.0%Not measuredOnly Claude Sonnet 4.6 measured
CorpFin (Vals AI)65.3%65.3%Tie
TaxEval (Vals AI)77.1%76.2%Claude Sonnet 4.6
MortgageTax (Vals AI)67.7%67.3%Claude Sonnet 4.6
MedQA (Vals AI)92.1%Not measuredOnly Claude Sonnet 4.6 measured
MedCode (Vals AI)Not measured43.4%Only GPT-5.6 Terra measured
SimpleQA Verified35.5%43.2%GPT-5.6 Terra
LMArena Text: science14741452Claude Sonnet 4.6
LMArena Text: medicine and healthcare14511430Claude Sonnet 4.6
LMArena Text: legal and government14701461Claude Sonnet 4.6
LMArena Text: business and finance14641448Claude Sonnet 4.6
FACTS Benchmark Suite37.0%52.0%GPT-5.6 Terra
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index72
Web design benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.6GPT-5.6 TerraLeader
Design Arena: websites12841268Claude Sonnet 4.6
Design Arena: UI components12691256Claude Sonnet 4.6
Design Arena: game dev12581229Claude Sonnet 4.6
Design Arena: data viz12781240Claude Sonnet 4.6
Design Arena: 3D12341134Claude Sonnet 4.6
Design Arena: all code categories12751240Claude Sonnet 4.6
Design Arena: SVG11961219GPT-5.6 Terra
Design Arena: ASCII art12351178Claude Sonnet 4.6
LiveBench design71.8%76.0%GPT-5.6 Terra
GeneralLike-for-likePublic boards, shown as published, kept out of the index1617
General benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.6GPT-5.6 TerraLeader
LiveBench data analysis76.1%79.3%GPT-5.6 Terra
Public Benefits Bench (Vals AI)62.5%62.4%Claude Sonnet 4.6
SAGE (Vals AI)46.6%47.0%GPT-5.6 Terra
MedScribe (Vals AI)Not measured82.9%Only GPT-5.6 Terra measured
Vals Multimodal Index60.6%65.1%GPT-5.6 Terra
IFBench56.6%71.2%GPT-5.6 Terra
Long context reasoning (AA-LCR)80.0%83.0%GPT-5.6 Terra
DTBench89.9%93.3%GPT-5.6 Terra
LMCA46.5%54.9%GPT-5.6 Terra
Surface Evolver BenchNot measured83.8%Only GPT-5.6 Terra measured
Furniture assemblyNot measured54.2%Only GPT-5.6 Terra measured
ExploitBench23.6%Not measuredOnly Claude Sonnet 4.6 measured
LMArena Text14581448Claude Sonnet 4.6
LMArena Text: instruction following14761456Claude Sonnet 4.6
LMArena Text: creative writing14351413Claude Sonnet 4.6
LMArena Vision12831271Claude Sonnet 4.6
LMArena Text: English14721449Claude Sonnet 4.6
LMArena Text: non-English14401441GPT-5.6 Terra
LMArena Text: Chinese14911514GPT-5.6 Terra
LMArena Text: German14281460GPT-5.6 Terra
LMArena Text: Japanese14201454GPT-5.6 Terra
LMArena Text: Korean14101427GPT-5.6 Terra
LMArena Text: French14651466GPT-5.6 Terra
LMArena Text: Spanish14641451Claude Sonnet 4.6
LMArena Text: Russian14401452GPT-5.6 Terra
LMArena Text: Polish14431446GPT-5.6 Terra
LMArena Text: multi-turn14641453Claude Sonnet 4.6
LMArena Text: longer queries14791454Claude Sonnet 4.6
LMArena Text: writing and language14441431Claude Sonnet 4.6
LMArena Text: entertainment and media14311418Claude Sonnet 4.6
LMArena Vision: English12981272Claude Sonnet 4.6
LMArena Vision: Chinese13071337GPT-5.6 Terra
LMArena Vision: reading text12961278Claude Sonnet 4.6
LMArena Vision: humor12481236Claude Sonnet 4.6
LMArena Vision: recognizing things1195Not measuredOnly Claude Sonnet 4.6 measured
LMArena Vision: creative writing12721248Claude Sonnet 4.6
LMArena Document14821472Claude Sonnet 4.6
EQ-Bench 412071234GPT-5.6 Terra
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
Image generation benchmarks for Claude Sonnet 4.6 and GPT-5.6 Terra
BenchmarkClaude Sonnet 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 Sonnet 4.6$0.011Fits 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 Sonnet 4.6$0.195Fits 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 Sonnet 4.6$0.750Fits 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 Sonnet 4.6 and GPT-5.6 Terra
SpecificationAnthropic Claude Sonnet 4.6OpenAI GPT-5.6 Terra
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedFebruary 17, 2026July 9, 2026
Context window1M1.05M
Input $/Mtok$3.00$2.00
Output $/Mtok$15.00$12.00
Coding index57.363.9
Independent measurements behind it56
Cost per solved task$1.68$0.42
SourceOpenRouter listingOpenRouter listing

Questions

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

Pick GPT-5.6 Terra for coding: it scores 63.9 on the Vibe Coding Index against 57.3 for Claude Sonnet 4.6. Pick Claude Sonnet 4.6 for work measured by LMArena WebDev or LMArena Text: coding, where it leads.

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

Claude Sonnet 4.6 costs $3.00 per million input tokens and $15.00 per million output tokens; GPT-5.6 Terra costs $2.00 and $12.00. Per solved SWE-bench Verified task, Claude Sonnet 4.6 costs $1.68 and GPT-5.6 Terra $0.42.

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

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

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

109 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 4.6's coding index rests on 5 independent benchmarks and GPT-5.6 Terra's on 6. Where only one model has a result, the page says so instead of naming a winner.

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