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Claude Sonnet 4.5 vs GPT-5.6 Terra

GPT-5.6 Terra leads Claude Sonnet 4.5 on coding, 63.9 to 39.5 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; 77 benchmarks have a result for both.

Replace Claude Sonnet 4.5 Replace GPT-5.6 Terra
Claude Sonnet 4.5Anthropic
Coding
39.5
Overall
49.5
Output $/M
$15.00
19
GPT-5.6 TerraOpenAI
Coding
63.9
Overall
68.1
Output $/M
$12.00
58
vs boards won of 77 shared

Claude Sonnet 4.5 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 39.5 for Claude Sonnet 4.5.

Pick Claude Sonnet 4.5 for work measured by LMArena Text: coding or Design Arena: agents building mobile apps, where it leads.

Model AClaude Sonnet 4.5Anthropic39.5/1003 independent benchmarks$1.16 per solved taskModel BGPT-5.6 TerraOpenAI63.9/1006 independent benchmarks$0.42 per solved task
Shared results
77
Claude Sonnet 4.5 only
23
GPT-5.6 Terra only
52
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 4.5 39.5 from 3 benchmarks, GPT-5.6 Terra 63.9 from 6 benchmarks.
Widest category
Math, 35.5 points apart on average over 6 shared benchmarks.
Widest single gap
ARC-AGI-2: Claude Sonnet 4.5 13.6% against GPT-5.6 Terra 83.9%, 70.3 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 4.5 $15.00 against GPT-5.6 Terra $12.00 per million output tokens, 1.3x apart.
Context window
Claude Sonnet 4.5 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 4.5BarsGPT-5.6 TerraTies
Coding19
Intelligence02
Agentic work14
Reasoning39
Math06
Knowledge39
Web design26
General913
All shared boards1958
CodingLike-for-likeSix of these boards feed the Vibe Coding Index19
Coding benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-5.6 TerraLeader
SWE-bench Verified74.8%Not measuredOnly Claude Sonnet 4.5 measured
SWE-bench Multilingual67.0%Not measuredOnly Claude Sonnet 4.5 measured
LiveBench codingNot measured86.2%Only GPT-5.6 Terra measured
LMArena WebDev13941522GPT-5.6 Terra
AA Coding Index52.176.7GPT-5.6 Terra
LiveCodeBench (Vals AI)73.0%85.9%GPT-5.6 Terra
SWE-bench Verified (Vals AI)70.0%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)22.6%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)Not measured62.9%Only GPT-5.6 Terra measured
Terminal-Bench46.5%Not measuredOnly Claude Sonnet 4.5 measured
FrontierCodeNot measured41.3%Only GPT-5.6 Terra measured
GSO-Bench14.7%Not measuredOnly Claude Sonnet 4.5 measured
WeirdML47.7%78.3%GPT-5.6 Terra
Cybench60.0%Not measuredOnly Claude Sonnet 4.5 measured
ALE-BenchNot measured1951.4Only GPT-5.6 Terra measured
LMArena Text: coding14881485Claude Sonnet 4.5
LMArena Text: software and IT14731482GPT-5.6 Terra
LMArena WebDev: React13861513GPT-5.6 Terra
LMArena WebDev: HTML13991526GPT-5.6 Terra
LMArena WebDev: from an imageNot measured1541Only GPT-5.6 Terra measured
SciCodeNot measured10.8%Only GPT-5.6 Terra measured
SWE-Bench Pro V2Not measured92.4%Only GPT-5.6 Terra measured
Neither model has a result on the other 12 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-5.6 TerraLeader
AA Intelligence Index20.742.1GPT-5.6 Terra
Epoch Capabilities Index146.7160.1GPT-5.6 Terra
Agentic workLike-for-likePublic boards, shown as published, kept out of the index14
Agentic work benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-5.6 TerraLeader
AA Agentic Index15.843.2GPT-5.6 Terra
Design Arena: agents building web apps10601120GPT-5.6 Terra
Design Arena: agents building full-stack apps10501061GPT-5.6 Terra
Design Arena: agents building mobile apps11361110Claude Sonnet 4.5
Design Arena: agents building Android appsNot measured1060Only GPT-5.6 Terra measured
Design Arena: agents building gamesNot measured1083Only GPT-5.6 Terra measured
Design Arena: HTML slidesNot measured1047Only GPT-5.6 Terra measured
Design Arena: PowerPoint slidesNot measured1104Only 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 TelecomNot measured86.3%Only GPT-5.6 Terra measured
APEX-AgentsNot measured58.2%Only GPT-5.6 Terra measured
METR time horizons67.4%Not measuredOnly Claude Sonnet 4.5 measured
Remote Labor Index2.1%Not measuredOnly Claude Sonnet 4.5 measured
GDPval42.5%Not measuredOnly Claude Sonnet 4.5 measured
BALROGNot measured53.2%Only GPT-5.6 Terra measured
DeepResearch Bench52.6%Not measuredOnly Claude Sonnet 4.5 measured
OSWorld62.9%Not measuredOnly Claude Sonnet 4.5 measured
Vending-Bench 2$3,839$7,343GPT-5.6 Terra
Berkeley Function Calling Leaderboard (BFCL)73.2%Not measuredOnly Claude Sonnet 4.5 measured
MCP Atlas59.5%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 14 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index39
Reasoning benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-5.6 TerraLeader
GPQA Diamond81.6%90.9%GPT-5.6 Terra
LiveBench reasoningNot measured90.6%Only GPT-5.6 Terra measured
MMMU Pro (Vals AI)79.3%86.5%GPT-5.6 Terra
GPQA Diamond (Artificial Analysis run)Not measured92.5%Only GPT-5.6 Terra measured
Humanity's Last Exam (Artificial Analysis run)Not measured42.9%Only GPT-5.6 Terra measured
GPQA Diamond (Epoch AI run)82.3%93.3%GPT-5.6 Terra
ARC-AGI63.7%96.5%GPT-5.6 Terra
ARC-AGI-213.6%83.9%GPT-5.6 Terra
SimpleBench54.3%48.9%Claude Sonnet 4.5
Chess puzzles10.0%47.0%GPT-5.6 Terra
Mystery game puzzles17.0%35.0%GPT-5.6 Terra
EBR-bench2.4%Not measuredOnly Claude Sonnet 4.5 measured
VPCT39.8%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: hard prompts14621469GPT-5.6 Terra
LMArena Text: expert14831496GPT-5.6 Terra
LMArena Text: hard prompts in English14711465Claude Sonnet 4.5
LMArena Vision: diagramsNot measured1295Only GPT-5.6 Terra measured
LMArena Vision: homeworkNot measured1312Only GPT-5.6 Terra measured
Kagi LLM Benchmark57.9%51.3%Claude Sonnet 4.5
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index06
Math benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-5.6 TerraLeader
AIME88.2%Not measuredOnly Claude Sonnet 4.5 measured
MGSM (Vals AI)94.3%Not measuredOnly Claude Sonnet 4.5 measured
OTIS Mock AIME77.8%99.7%GPT-5.6 Terra
FrontierMath, tiers 1 to 323.9%86.0%GPT-5.6 Terra
FrontierMath, tier 42.4%70.7%GPT-5.6 Terra
ProofBench19.0%74.0%GPT-5.6 Terra
MATH level 597.7%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: math14491465GPT-5.6 Terra
LMArena Text: mathematical work14621478GPT-5.6 Terra
MathArena12.6%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 4 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index39
Knowledge benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-5.6 TerraLeader
MMLU Pro87.4%86.7%Claude Sonnet 4.5
LegalBench (Vals AI)84.1%85.1%GPT-5.6 Terra
CaseLaw (Vals AI)62.2%Not measuredOnly Claude Sonnet 4.5 measured
CorpFin (Vals AI)62.0%65.3%GPT-5.6 Terra
TaxEval (Vals AI)73.3%76.2%GPT-5.6 Terra
MortgageTax (Vals AI)64.0%67.3%GPT-5.6 Terra
MedQA (Vals AI)94.7%Not measuredOnly Claude Sonnet 4.5 measured
MedCode (Vals AI)44.1%43.4%Claude Sonnet 4.5
SimpleQA Verified30.7%43.2%GPT-5.6 Terra
LMArena Text: science14481452GPT-5.6 Terra
LMArena Text: medicine and healthcare14441430Claude Sonnet 4.5
LMArena Text: legal and government14511461GPT-5.6 Terra
LMArena Text: business and finance14401448GPT-5.6 Terra
FACTS Benchmark Suite40.6%52.0%GPT-5.6 Terra
PRBench Finance43.8%Not measuredOnly Claude Sonnet 4.5 measured
PRBench Legal40.8%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index26
Web design benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-5.6 TerraLeader
Design Arena: websites11891268GPT-5.6 Terra
Design Arena: UI components11701256GPT-5.6 Terra
Design Arena: game dev11661229GPT-5.6 Terra
Design Arena: data viz11671240GPT-5.6 Terra
Design Arena: 3D11571134Claude Sonnet 4.5
Design Arena: all code categories11821240GPT-5.6 Terra
Design Arena: SVG11141219GPT-5.6 Terra
Design Arena: ASCII art12051178Claude Sonnet 4.5
LiveBench designNot measured76.0%Only GPT-5.6 Terra measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index913
General benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-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)36.1%47.0%GPT-5.6 Terra
MedScribe (Vals AI)84.5%82.9%Claude Sonnet 4.5
Vals Multimodal IndexNot measured65.1%Only GPT-5.6 Terra measured
IFBenchNot measured71.2%Only GPT-5.6 Terra measured
Long context reasoning (AA-LCR)Not measured83.0%Only GPT-5.6 Terra measured
DTBench83.2%93.3%GPT-5.6 Terra
LMCA38.8%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
LMArena Text14381448GPT-5.6 Terra
LMArena Text: instruction following14591456Claude Sonnet 4.5
LMArena Text: creative writing14421413Claude Sonnet 4.5
LMArena VisionNot measured1271Only GPT-5.6 Terra measured
LMArena Text: English14501449Claude Sonnet 4.5
LMArena Text: non-English14251441GPT-5.6 Terra
LMArena Text: Chinese14601514GPT-5.6 Terra
LMArena Text: German14271460GPT-5.6 Terra
LMArena Text: Japanese13901454GPT-5.6 Terra
LMArena Text: Korean14021427GPT-5.6 Terra
LMArena Text: French14591466GPT-5.6 Terra
LMArena Text: Spanish14581451Claude Sonnet 4.5
LMArena Text: Russian14371452GPT-5.6 Terra
LMArena Text: Polish14231446GPT-5.6 Terra
LMArena Text: multi-turn14651453Claude Sonnet 4.5
LMArena Text: longer queries14751454Claude Sonnet 4.5
LMArena Text: writing and language14421431Claude Sonnet 4.5
LMArena Text: entertainment and media14281418Claude Sonnet 4.5
LMArena Vision: EnglishNot measured1272Only GPT-5.6 Terra measured
LMArena Vision: ChineseNot measured1337Only GPT-5.6 Terra measured
LMArena Vision: reading textNot measured1278Only GPT-5.6 Terra measured
LMArena Vision: humorNot measured1236Only GPT-5.6 Terra measured
LMArena Vision: creative writingNot measured1248Only GPT-5.6 Terra measured
LMArena Document14501472GPT-5.6 Terra
MultiChallenge55.3%Not measuredOnly Claude Sonnet 4.5 measured
EQ-Bench 4Not measured1234Only GPT-5.6 Terra measured
Neither model has a result on the other 11 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Sonnet 4.5 and GPT-5.6 Terra
BenchmarkClaude Sonnet 4.5GPT-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 4.5$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 4.5$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 4.5$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 4.5 and GPT-5.6 Terra
SpecificationAnthropic Claude Sonnet 4.5OpenAI GPT-5.6 Terra
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 29, 2025July 9, 2026
Context window1M1.05M
Input $/Mtok$3.00$2.00
Output $/Mtok$15.00$12.00
Coding index39.563.9
Independent measurements behind it36
Cost per solved task$1.16$0.42
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 4.5 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 39.5 for Claude Sonnet 4.5. Pick Claude Sonnet 4.5 for work measured by LMArena Text: coding or Design Arena: agents building mobile apps, where it leads.

Which is cheaper, Claude Sonnet 4.5 or GPT-5.6 Terra?

Claude Sonnet 4.5 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 4.5 costs $1.16 and GPT-5.6 Terra $0.42.

Which has the bigger context window, Claude Sonnet 4.5 or GPT-5.6 Terra?

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

How many benchmarks is the Claude Sonnet 4.5 vs GPT-5.6 Terra comparison based on?

77 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 4.5's coding index rests on 3 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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