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Claude Opus 5 vs GPT-5.6 Terra

Claude Opus 5 leads GPT-5.6 Terra on coding, 83.0 to 63.9 on the Vibe Coding Index, and GPT-5.6 Terra costs 2.1x less per output token ($12.00 vs $25.00 per million). Updated October 22, 2026; 120 benchmarks have a result for both.

Replace Claude Opus 5 Replace GPT-5.6 Terra
Claude Opus 5Anthropic
Coding
83.0
Overall
81.6
Output $/M
$25.00
111
GPT-5.6 TerraOpenAI
Coding
63.9
Overall
68.1
Output $/M
$12.00
8
vs boards won of 120 shared, 1 tied

Claude Opus 5 or GPT-5.6 Terra: which to pick

Pick Claude Opus 5 for coding: it scores 83.0 on the Vibe Coding Index against 63.9 for GPT-5.6 Terra.

Pick GPT-5.6 Terra for output tokens 2.1x cheaper ($12.00 vs $25.00 per million) and a lower cost per solved task ($0.42 against $1.33).

Model AClaude Opus 5Anthropic83.0/1006 independent benchmarks$1.33 per solved taskModel BGPT-5.6 TerraOpenAI63.9/1006 independent benchmarks$0.42 per solved task
Shared results
120
Claude Opus 5 only
11
GPT-5.6 Terra only
7
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 Opus 5 83.0 from 6 benchmarks, GPT-5.6 Terra 63.9 from 6 benchmarks.
Widest category
Agentic work, 15.8 points apart on average over 19 shared benchmarks.
Widest single gap
Terminal-Bench 4 (Vals AI): Claude Opus 5 53.5% against GPT-5.6 Terra 22.7%, 41.1 points apart on a 0 to 100 scale.
Output price
Claude Opus 5 $25.00 against GPT-5.6 Terra $12.00 per million output tokens, 2.1x apart.
Context window
Claude Opus 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 Opus 5BarsGPT-5.6 TerraTies
Coding222
Intelligence20
Agentic work1801 tie
Reasoning151
Math42
Knowledge101
Web design90
General312
All shared boards11181 tie
CodingLike-for-likeSix of these boards feed the Vibe Coding Index222
Coding benchmarks for Claude Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 5GPT-5.6 TerraLeader
LiveBench coding90.8%86.2%Claude Opus 5
LMArena WebDev16891522Claude Opus 5
AA Coding Index78.076.7Claude Opus 5
LiveCodeBench (Vals AI)89.0%85.9%Claude Opus 5
SWE-bench Verified (Vals AI)97.0%95.4%Claude Opus 5
Terminal-Bench 4 (Vals AI)53.5%22.7%Claude Opus 5
Vibe Code Bench (Vals AI)88.4%74.6%Claude Opus 5
Code migration (Vals AI)57.5%47.8%Claude Opus 5
ProgramBench (Vals AI)3.0%0.5%Claude Opus 5
IOI (Vals AI)84.3%87.6%GPT-5.6 Terra
Terminal-Bench 2.1 (Vals AI)84.6%77.5%Claude Opus 5
Vibe Code Bench 1-100 (Vals AI)28.5%14.8%Claude Opus 5
SkillsBench (Vals AI)60.4%58.9%Claude Opus 5
CyberBench (Vals AI)65.4%72.1%GPT-5.6 Terra
SciCode56.4%55.0%Claude Opus 5
Terminal-Bench Hard (Artificial Analysis run)Not measured62.9%Only GPT-5.6 Terra measured
FrontierCode53.4%41.3%Claude Opus 5
FrontierSWE52.0%Not measuredOnly Claude Opus 5 measured
WeirdML91.8%78.3%Claude Opus 5
ALE-Bench2164.61951.4Claude Opus 5
LMArena Text: coding15331485Claude Opus 5
LMArena Text: software and IT15271482Claude Opus 5
LMArena WebDev: React17111513Claude Opus 5
LMArena WebDev: HTML16801526Claude Opus 5
LMArena WebDev: from an image16621541Claude Opus 5
SciCode13.8%10.8%Claude Opus 5
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 5GPT-5.6 TerraLeader
AA Intelligence Index50.842.1Claude Opus 5
Epoch Capabilities Index163.9160.1Claude Opus 5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index180
Agentic work benchmarks for Claude Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 5GPT-5.6 TerraLeader
AA Agentic Index56.543.2Claude Opus 5
Design Arena: agents building web apps12661120Claude Opus 5
Design Arena: agents building full-stack apps13061061Claude Opus 5
Design Arena: agents building mobile apps13481111Claude Opus 5
Design Arena: agents building Android apps12571062Claude Opus 5
Design Arena: agents building Godot games1279Not measuredOnly Claude Opus 5 measured
Design Arena: agents building games12611083Claude Opus 5
Design Arena: HTML slidesNot measured1058Only GPT-5.6 Terra measured
Design Arena: PowerPoint slides12401105Claude Opus 5
LiveBench research88.9%60.4%Claude Opus 5
LiveBench browser84.0%84.0%Tie
LiveBench long agentic62.1%48.4%Claude Opus 5
SREBench (Vals AI)12.2%9.5%Claude Opus 5
Finance Agent (Vals AI)58.6%54.4%Claude Opus 5
Tax Agent Bench (Vals AI)45.5%30.0%Claude Opus 5
Legal Research Bench (Vals AI)55.3%41.4%Claude Opus 5
Excel Modeling Benchmark (Vals AI)73.6%66.2%Claude Opus 5
BioMysteryBench (Vals AI)79.3%Not measuredOnly Claude Opus 5 measured
Terminal-Bench-Science (Vals AI)27.1%10.0%Claude Opus 5
Vals Science Index47.9%Not measuredOnly Claude Opus 5 measured
Time Horizon Index (Vals AI)18.8%Not measuredOnly Claude Opus 5 measured
CUA-bench (Vals AI)9.0%Not measuredOnly Claude Opus 5 measured
τ²-Bench TelecomNot measured86.3%Only GPT-5.6 Terra measured
APEX-Agents65.8%58.2%Claude Opus 5
OSWorld 2.031.4%Not measuredOnly Claude Opus 5 measured
BALROG63.4%53.2%Claude Opus 5
PostTrainBench35.0%Not measuredOnly Claude Opus 5 measured
Vending-Bench 2$11,182$7,343Claude Opus 5
LMArena Search1242Not measuredOnly Claude Opus 5 measured
Neither model has a result on the other 12 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index151
Reasoning benchmarks for Claude Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 5GPT-5.6 TerraLeader
GPQA Diamond93.4%90.9%Claude Opus 5
LiveBench reasoning91.2%90.6%Claude Opus 5
MysteryMechanism (Vals AI)37.4%Not measuredOnly Claude Opus 5 measured
MMMU Pro (Vals AI)89.9%86.5%Claude Opus 5
GPQA Diamond (Artificial Analysis run)93.7%92.5%Claude Opus 5
Humanity's Last Exam (Artificial Analysis run)54.9%42.9%Claude Opus 5
GPQA Diamond (Epoch AI run)93.9%93.3%Claude Opus 5
ARC-AGI97.5%96.5%Claude Opus 5
ARC-AGI-290.4%83.9%Claude Opus 5
SimpleBench80.6%48.9%Claude Opus 5
Chess puzzles43.0%47.0%GPT-5.6 Terra
Mystery game puzzles59.0%35.0%Claude Opus 5
EBR-bench45.7%Not measuredOnly Claude Opus 5 measured
LMArena Text: hard prompts15271469Claude Opus 5
LMArena Text: expert15541496Claude Opus 5
LMArena Text: hard prompts in English15231465Claude Opus 5
LMArena Vision: diagrams13481295Claude Opus 5
LMArena Vision: homework13381312Claude Opus 5
Kagi LLM BenchmarkNot measured51.3%Only GPT-5.6 Terra measured
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index42
Math benchmarks for Claude Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 5GPT-5.6 TerraLeader
OTIS Mock AIME98.9%99.7%GPT-5.6 Terra
FrontierMath, tiers 1 to 385.6%86.0%GPT-5.6 Terra
FrontierMath, tier 473.2%70.7%Claude Opus 5
ProofBench99.0%74.0%Claude Opus 5
LMArena Text: math15331465Claude Opus 5
LMArena Text: mathematical work15441478Claude Opus 5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index101
Knowledge benchmarks for Claude Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 5GPT-5.6 TerraLeader
MMLU Pro91.6%86.7%Claude Opus 5
LegalBench (Vals AI)87.0%85.1%Claude Opus 5
CorpFin (Vals AI)73.2%65.3%Claude Opus 5
TaxEval (Vals AI)75.1%76.2%GPT-5.6 Terra
MortgageTax (Vals AI)72.1%67.3%Claude Opus 5
MedCode (Vals AI)63.6%43.4%Claude Opus 5
SimpleQA Verified59.9%43.2%Claude Opus 5
LMArena Text: science15311452Claude Opus 5
LMArena Text: medicine and healthcare15251430Claude Opus 5
LMArena Text: legal and government15301461Claude Opus 5
LMArena Text: business and finance15011448Claude Opus 5
FACTS Benchmark SuiteNot measured52.0%Only GPT-5.6 Terra measured
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index90
Web design benchmarks for Claude Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 5GPT-5.6 TerraLeader
Design Arena: websites13091268Claude Opus 5
Design Arena: UI components13461256Claude Opus 5
Design Arena: game dev13371229Claude Opus 5
Design Arena: data viz13291240Claude Opus 5
Design Arena: 3D13341134Claude Opus 5
Design Arena: all code categories13231241Claude Opus 5
Design Arena: SVG13111219Claude Opus 5
Design Arena: ASCII art13521177Claude Opus 5
LiveBench design83.0%76.0%Claude Opus 5
GeneralLike-for-likePublic boards, shown as published, kept out of the index312
General benchmarks for Claude Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 5GPT-5.6 TerraLeader
LiveBench data analysis74.6%79.3%GPT-5.6 Terra
Public Benefits Bench (Vals AI)76.9%62.4%Claude Opus 5
SAGE (Vals AI)49.4%47.0%Claude Opus 5
MedScribe (Vals AI)91.0%82.9%Claude Opus 5
Vals Multimodal Index73.9%65.1%Claude Opus 5
IFBenchNot measured71.2%Only GPT-5.6 Terra measured
Long context reasoning (AA-LCR)82.0%83.0%GPT-5.6 Terra
DTBench97.9%93.3%Claude Opus 5
LMCA64.5%54.9%Claude Opus 5
Surface Evolver BenchNot measured83.8%Only GPT-5.6 Terra measured
Furniture assembly60.8%54.2%Claude Opus 5
LMArena Text15091448Claude Opus 5
LMArena Text: instruction following15181456Claude Opus 5
LMArena Text: creative writing14931413Claude Opus 5
LMArena Vision13201271Claude Opus 5
LMArena Text: English15081449Claude Opus 5
LMArena Text: non-English15021441Claude Opus 5
LMArena Text: Chinese15731514Claude Opus 5
LMArena Text: German15271460Claude Opus 5
LMArena Text: Japanese15201454Claude Opus 5
LMArena Text: Korean15171427Claude Opus 5
LMArena Text: French15191466Claude Opus 5
LMArena Text: Spanish15231451Claude Opus 5
LMArena Text: Russian15071452Claude Opus 5
LMArena Text: Polish15221446Claude Opus 5
LMArena Text: multi-turn15001453Claude Opus 5
LMArena Text: longer queries15171454Claude Opus 5
LMArena Text: writing and language14991431Claude Opus 5
LMArena Text: entertainment and media14811418Claude Opus 5
LMArena Vision: English13151272Claude Opus 5
LMArena Vision: Chinese14001337Claude Opus 5
LMArena Vision: reading text13291278Claude Opus 5
LMArena Vision: humor12931236Claude Opus 5
LMArena Vision: creative writing13131248Claude Opus 5
LMArena Document15161472Claude Opus 5
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 Opus 5 and GPT-5.6 Terra
BenchmarkClaude Opus 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 Opus 5$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 5$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 5$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 5 and GPT-5.6 Terra
SpecificationAnthropic Claude Opus 5OpenAI GPT-5.6 Terra
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJuly 24, 2026July 9, 2026
Context window1M1.05M
Input $/Mtok$5.00$2.00
Output $/Mtok$25.00$12.00
Coding index83.063.9
Independent measurements behind it66
Cost per solved task$1.33$0.42
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 5 better than GPT-5.6 Terra for coding?

Pick Claude Opus 5 for coding: it scores 83.0 on the Vibe Coding Index against 63.9 for GPT-5.6 Terra. Pick GPT-5.6 Terra for output tokens 2.1x cheaper ($12.00 vs $25.00 per million) and a lower cost per solved task ($0.42 against $1.33).

Which is cheaper, Claude Opus 5 or GPT-5.6 Terra?

Claude Opus 5 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 5 costs $1.33 and GPT-5.6 Terra $0.42.

Which has the bigger context window, Claude Opus 5 or GPT-5.6 Terra?

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

How many benchmarks is the Claude Opus 5 vs GPT-5.6 Terra comparison based on?

120 benchmarks have a result for both models as of October 22, 2026. Claude Opus 5's coding index rests on 6 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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