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Claude Sonnet 5.5 vs GPT-5.6 Sol

Updated October 21, 2026. 89 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Sonnet 5.5 Replace GPT-5.6 Sol
Claude Sonnet 5.5Anthropic
Coding
88.9
Overall
56.0
Output $/M
$10.00
71
GPT-5.6 SolOpenAI
Coding
76.7
Overall
47.0
Output $/M
$20.00
15
vs boards won of 89 shared, 3 tied

Decision reading

Pick Claude Sonnet 5.5 for coding: it scores 88.9 on the Vibe Coding Index against 76.7 for GPT-5.6 Sol.

Pick GPT-5.6 Sol when the context window is larger, 1.05M against 1M tokens, or when what matters is IOI (Vals AI) or Terminal-Bench 2.1 (Vals AI), where it leads.

Model AClaude Sonnet 5.5Anthropic88.9/1002 independent benchmarksNo cost per solved taskModel BGPT-5.6 SolOpenAI76.7/1002 independent benchmarks$1.20 per solved task
Shared results
89
Claude Sonnet 5.5 only
6
GPT-5.6 Sol only
47
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 Sonnet 5.5 88.9 from 2 benchmarks, GPT-5.6 Sol 76.7 from 2 benchmarks.
Widest category
Agentic work, 11.1 points apart on average over 14 shared benchmarks.
Widest single gap
LiveBench long agentic: Claude Sonnet 5.5 78.8% against GPT-5.6 Sol 48.5%, 30.3 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 5.5 $10.00 against GPT-5.6 Sol $20.00 per million output tokens, 2.0x apart.
Context window
Claude Sonnet 5.5 takes 1M tokens, GPT-5.6 Sol 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 5.5BarsGPT-5.6 SolTies
Coding144
Intelligence20
Agentic work1121 tie
Reasoning911 tie
Math321 tie
Knowledge51
Web design70
General205
All shared boards71153 ties
CodingLike-for-likeFour of these boards feed the Vibe Coding Index144
Coding benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
LiveBench coding94.7%89.7%Claude Sonnet 5.5
LMArena WebDev17681616Claude Sonnet 5.5
AA Coding IndexNot measured77.4Only GPT-5.6 Sol measured
LiveCodeBench (Vals AI)Not measured82.6%Only GPT-5.6 Sol measured
SWE-bench Verified (Vals AI)Not measured96.2%Only GPT-5.6 Sol measured
Terminal-Bench 4 (Vals AI)64.1%37.9%Claude Sonnet 5.5
Vibe Code Bench (Vals AI)92.4%80.5%Claude Sonnet 5.5
Code migration (Vals AI)69.8%52.9%Claude Sonnet 5.5
ProgramBench (Vals AI)6.5%1.5%Claude Sonnet 5.5
IOI (Vals AI)83.1%91.2%GPT-5.6 Sol
Terminal-Bench 2.1 (Vals AI)83.2%85.8%GPT-5.6 Sol
SWE-bench Multimodal (Vals AI)58.3%Not measuredOnly Claude Sonnet 5.5 measured
Vibe Code Bench 1-100 (Vals AI)Not measured20.0%Only GPT-5.6 Sol measured
SkillsBench (Vals AI)Not measured54.1%Only GPT-5.6 Sol measured
CyberBench (Vals AI)59.6%76.3%GPT-5.6 Sol
SciCode61.0%57.8%Claude Sonnet 5.5
Terminal-Bench Hard (Artificial Analysis run)Not measured65.9%Only GPT-5.6 Sol measured
FrontierCode52.1%47.5%Claude Sonnet 5.5
FrontierSWE61.9%32.2%Claude Sonnet 5.5
GSO-BenchNot measured76.5%Only GPT-5.6 Sol measured
WeirdMLNot measured88.8%Only GPT-5.6 Sol measured
MirrorCodeNot measured20.0%Only GPT-5.6 Sol measured
ALE-Bench1819.12176.9GPT-5.6 Sol
LMArena Text: coding15131496Claude Sonnet 5.5
LMArena Text: software and IT15041489Claude Sonnet 5.5
LMArena WebDev: React18171620Claude Sonnet 5.5
LMArena WebDev: HTML17411618Claude Sonnet 5.5
LMArena WebDev: from an image17371609Claude Sonnet 5.5
Neither model has a result on the other 10 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
AA Intelligence Index56.047.0Claude Sonnet 5.5
Epoch Capabilities Index166.2162.8Claude Sonnet 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index112
Agentic work benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
AA Agentic IndexNot measured50.2Only GPT-5.6 Sol measured
Design Arena: agents building web apps13031245Claude Sonnet 5.5
Design Arena: agents building full-stack appsNot measured1261Only GPT-5.6 Sol measured
Design Arena: agents building mobile apps12651249Claude Sonnet 5.5
Design Arena: agents building Android appsNot measured1246Only GPT-5.6 Sol measured
Design Arena: agents building Godot gamesNot measured1260Only GPT-5.6 Sol measured
Design Arena: agents building gamesNot measured1267Only GPT-5.6 Sol measured
Design Arena: HTML slidesNot measured1286Only GPT-5.6 Sol measured
Design Arena: PowerPoint slidesNot measured1240Only GPT-5.6 Sol measured
Design Arena: spreadsheets1245Not measuredOnly Claude Sonnet 5.5 measured
LiveBench research83.6%54.5%Claude Sonnet 5.5
LiveBench browser84.0%88.0%GPT-5.6 Sol
LiveBench long agentic78.8%48.5%Claude Sonnet 5.5
SREBench (Vals AI)30.1%30.5%GPT-5.6 Sol
Finance Agent (Vals AI)58.1%53.8%Claude Sonnet 5.5
Tax Agent Bench (Vals AI)42.0%31.1%Claude Sonnet 5.5
Legal Research Bench (Vals AI)48.1%48.1%Tie
Harvey's Legal Agent Benchmark (Vals AI)10.4%Not measuredOnly Claude Sonnet 5.5 measured
Excel Modeling Benchmark (Vals AI)75.7%72.3%Claude Sonnet 5.5
BioMysteryBench (Vals AI)81.1%71.1%Claude Sonnet 5.5
Terminal-Bench-Science (Vals AI)47.1%20.0%Claude Sonnet 5.5
Vals Science Index59.1%41.5%Claude Sonnet 5.5
Time Horizon Index (Vals AI)Not measured23.8%Only GPT-5.6 Sol measured
CUA-bench (Vals AI)Not measured8.3%Only GPT-5.6 Sol measured
τ²-Bench TelecomNot measured85.1%Only GPT-5.6 Sol measured
APEX-Agents75.5%Not measuredOnly Claude Sonnet 5.5 measured
OSWorld 2.0Not measured27.3%Only GPT-5.6 Sol measured
BALROGNot measured60.0%Only GPT-5.6 Sol measured
PostTrainBenchNot measured36.2%Only GPT-5.6 Sol measured
SpireClimb1.3%Not measuredOnly Claude Sonnet 5.5 measured
Vending-Bench 2$11,165$9,619Claude Sonnet 5.5
LMArena SearchNot measured1261Only GPT-5.6 Sol measured
Neither model has a result on the other 7 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index91
Reasoning benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
GPQA DiamondNot measured95.2%Only GPT-5.6 Sol measured
LiveBench reasoning91.6%91.7%GPT-5.6 Sol
MysteryMechanism (Vals AI)49.1%33.3%Claude Sonnet 5.5
MMMU Pro (Vals AI)Not measured88.8%Only GPT-5.6 Sol measured
GPQA Diamond (Artificial Analysis run)Not measured94.1%Only GPT-5.6 Sol measured
Humanity's Last Exam (Artificial Analysis run)55.0%49.5%Claude Sonnet 5.5
GPQA Diamond (Epoch AI run)95.6%93.5%Claude Sonnet 5.5
ARC-AGINot measured97.5%Only GPT-5.6 Sol measured
ARC-AGI-2Not measured92.5%Only GPT-5.6 Sol measured
SimpleBenchNot measured64.8%Only GPT-5.6 Sol measured
Chess puzzles59.0%59.0%Tie
Mystery game puzzles65.0%58.0%Claude Sonnet 5.5
EBR-benchNot measured44.8%Only GPT-5.6 Sol measured
LMArena Text: hard prompts14941483Claude Sonnet 5.5
LMArena Text: expert15311517Claude Sonnet 5.5
LMArena Text: hard prompts in English15021477Claude Sonnet 5.5
LMArena Vision: diagrams13291305Claude Sonnet 5.5
LMArena Vision: homework13311305Claude Sonnet 5.5
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index32
Math benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
OTIS Mock AIME100.0%100.0%Tie
FrontierMath, tiers 1 to 388.8%89.1%GPT-5.6 Sol
FrontierMath, tier 480.5%82.9%GPT-5.6 Sol
ProofBench100.0%83.0%Claude Sonnet 5.5
LMArena Text: math14971473Claude Sonnet 5.5
LMArena Text: mathematical work15101496Claude Sonnet 5.5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index51
Knowledge benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
MMLU ProNot measured89.1%Only GPT-5.6 Sol measured
LegalBench (Vals AI)Not measured87.0%Only GPT-5.6 Sol measured
CorpFin (Vals AI)Not measured64.4%Only GPT-5.6 Sol measured
TaxEval (Vals AI)Not measured74.8%Only GPT-5.6 Sol measured
MortgageTax (Vals AI)Not measured67.3%Only GPT-5.6 Sol measured
MedCode (Vals AI)52.9%44.0%Claude Sonnet 5.5
SimpleQA Verified46.5%69.7%GPT-5.6 Sol
LMArena Text: science14831455Claude Sonnet 5.5
LMArena Text: medicine and healthcare14641431Claude Sonnet 5.5
LMArena Text: legal and government14831476Claude Sonnet 5.5
LMArena Text: business and finance14681457Claude Sonnet 5.5
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index70
Web design benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
Design Arena: websites13261321Claude Sonnet 5.5
Design Arena: UI components13671338Claude Sonnet 5.5
Design Arena: game dev14691368Claude Sonnet 5.5
Design Arena: data viz13891323Claude Sonnet 5.5
Design Arena: 3D14581385Claude Sonnet 5.5
Design Arena: all code categories13641341Claude Sonnet 5.5
Design Arena: SVGNot measured1316Only GPT-5.6 Sol measured
Design Arena: ASCII artNot measured1302Only GPT-5.6 Sol measured
LiveBench design85.0%81.6%Claude Sonnet 5.5
GeneralLike-for-likePublic boards, shown as published, kept out of the index205
General benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
Vals Index70.8%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench data analysis59.5%79.8%GPT-5.6 Sol
Public Benefits Bench (Vals AI)67.2%66.5%Claude Sonnet 5.5
SAGE (Vals AI)51.8%52.6%GPT-5.6 Sol
MedScribe (Vals AI)91.1%85.2%Claude Sonnet 5.5
Vals Multimodal IndexNot measured72.6%Only GPT-5.6 Sol measured
IFBenchNot measured72.7%Only GPT-5.6 Sol measured
Long context reasoning (AA-LCR)82.7%84.0%GPT-5.6 Sol
DTBench97.3%95.7%Claude Sonnet 5.5
LMCA68.3%58.5%Claude Sonnet 5.5
Surface Evolver BenchNot measured93.1%Only GPT-5.6 Sol measured
Furniture assembly75.0%56.7%Claude Sonnet 5.5
LMArena Text14731457Claude Sonnet 5.5
LMArena Text: instruction following14921483Claude Sonnet 5.5
LMArena Text: creative writing14671449Claude Sonnet 5.5
LMArena Vision12871281Claude Sonnet 5.5
LMArena Text: English14841457Claude Sonnet 5.5
LMArena Text: non-English14561451Claude Sonnet 5.5
LMArena Text: Chinese15351525Claude Sonnet 5.5
LMArena Text: GermanNot measured1476Only GPT-5.6 Sol measured
LMArena Text: JapaneseNot measured1472Only GPT-5.6 Sol measured
LMArena Text: KoreanNot measured1442Only GPT-5.6 Sol measured
LMArena Text: French14991472Claude Sonnet 5.5
LMArena Text: Spanish14511443Claude Sonnet 5.5
LMArena Text: Russian14541471GPT-5.6 Sol
LMArena Text: PolishNot measured1459Only GPT-5.6 Sol measured
LMArena Text: multi-turn14651461Claude Sonnet 5.5
LMArena Text: longer queries14951481Claude Sonnet 5.5
LMArena Text: writing and language14741462Claude Sonnet 5.5
LMArena Text: entertainment and media14611450Claude Sonnet 5.5
LMArena Vision: English12891280Claude Sonnet 5.5
LMArena Vision: ChineseNot measured1313Only GPT-5.6 Sol measured
LMArena Vision: reading text12971290Claude Sonnet 5.5
LMArena Vision: humorNot measured1246Only GPT-5.6 Sol measured
LMArena Vision: creative writing12421283GPT-5.6 Sol
LMArena DocumentNot measured1483Only GPT-5.6 Sol 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
Image generation benchmarks for Claude Sonnet 5.5 and GPT-5.6 Sol
BenchmarkClaude Sonnet 5.5GPT-5.6 SolLeader
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 5.5$0.0070Fits in one request
GPT-5.6 Sol$0.014Fits in one request

Claude Sonnet 5.5 costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 5.5$0.130Fits in one request
GPT-5.6 Sol$0.260Fits in one request

Claude Sonnet 5.5 costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 5.5$0.500Fits in one request
GPT-5.6 Sol$1.00Fits in one request

Claude Sonnet 5.5 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 5.5 and GPT-5.6 Sol
SpecificationAnthropic Claude Sonnet 5.5OpenAI GPT-5.6 Sol
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 28, 2026July 9, 2026
Context window1M1.05M
Input $/Mtok$2.00$4.00
Output $/Mtok$10.00$20.00
Coding index88.976.7
Independent measurements behind it22
Cost per solved taskNot computable$1.20
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 5.5 better than GPT-5.6 Sol for coding?

Pick Claude Sonnet 5.5 for coding: it scores 88.9 on the Vibe Coding Index against 76.7 for GPT-5.6 Sol. Pick GPT-5.6 Sol when the context window is larger, 1.05M against 1M tokens, or when what matters is IOI (Vals AI) or Terminal-Bench 2.1 (Vals AI), where it leads.

Which is cheaper, Claude Sonnet 5.5 or GPT-5.6 Sol?

Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; GPT-5.6 Sol costs $4.00 and $20.00. Cost per solved task is known for GPT-5.6 Sol only.

Which has the bigger context window, Claude Sonnet 5.5 or GPT-5.6 Sol?

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

How many benchmarks is the Claude Sonnet 5.5 vs GPT-5.6 Sol comparison based on?

89 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 5.5's coding index rests on 2 independent benchmarks and GPT-5.6 Sol's on 2. Where only one model has a result, the page says so instead of naming a winner.

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