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Claude Sonnet 5.5 vs GPT-6.1 Sol

Updated October 21, 2026. 91 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-6.1 Sol
Claude Sonnet 5.5Anthropic
Coding
88.9
Overall
56.0
Output $/M
$10.00
64
GPT-6.1 SolOpenAI
Coding
88.7
Overall
51.8
Output $/M
$10.00
26
vs boards won of 91 shared, 1 tied

Decision reading

Claude Sonnet 5.5 and GPT-6.1 Sol are level for coding, 88.9 against 88.7 on the Vibe Coding Index, so price and context decide.

Pick GPT-6.1 Sol when the context window is larger, 1.05M against 1M tokens, or when what matters is LiveBench coding or IOI (Vals AI), where it leads. Pick Claude Sonnet 5.5 when what matters is LMArena WebDev or Terminal-Bench 4 (Vals AI), where it leads.

Model AClaude Sonnet 5.5Anthropic88.9/1002 independent benchmarksNo cost per solved taskModel BGPT-6.1 SolOpenAI88.7/1002 independent benchmarksNo cost per solved task
Shared results
91
Claude Sonnet 5.5 only
4
GPT-6.1 Sol only
4
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-6.1 Sol 88.7 from 2 benchmarks.
Widest category
Agentic work, 8.3 points apart on average over 16 shared benchmarks.
Widest single gap
ALE-Bench: Claude Sonnet 5.5 1819.1 against GPT-6.1 Sol 2743.8, 30.8 points apart on a 0 to 100 scale.
Output price
Both cost $10.00 per million output tokens.
Context window
Claude Sonnet 5.5 takes 1M tokens, GPT-6.1 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-6.1 SolTies
Coding134
Intelligence11
Agentic work106
Reasoning74
Math231 tie
Knowledge51
Web design61
General206
All shared boards64261 tie
CodingLike-for-likeFour of these boards feed the Vibe Coding Index134
Coding benchmarks for Claude Sonnet 5.5 and GPT-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 SolLeader
LiveBench coding94.7%96.0%GPT-6.1 Sol
LMArena WebDev17681753Claude Sonnet 5.5
Terminal-Bench 4 (Vals AI)64.1%55.0%Claude Sonnet 5.5
Vibe Code Bench (Vals AI)92.4%88.9%Claude Sonnet 5.5
Code migration (Vals AI)69.8%65.1%Claude Sonnet 5.5
ProgramBench (Vals AI)6.5%3.0%Claude Sonnet 5.5
IOI (Vals AI)83.1%96.9%GPT-6.1 Sol
Terminal-Bench 2.1 (Vals AI)83.2%Not measuredOnly Claude Sonnet 5.5 measured
SWE-bench Multimodal (Vals AI)58.3%43.5%Claude Sonnet 5.5
CyberBench (Vals AI)59.6%39.3%Claude Sonnet 5.5
SciCode61.0%55.8%Claude Sonnet 5.5
FrontierCode52.1%50.2%Claude Sonnet 5.5
FrontierSWE61.9%Not measuredOnly Claude Sonnet 5.5 measured
ALE-Bench1819.12743.8GPT-6.1 Sol
LMArena Text: coding15131478Claude Sonnet 5.5
LMArena Text: software and IT15041476Claude Sonnet 5.5
LMArena WebDev: React18171754Claude Sonnet 5.5
LMArena WebDev: HTML17411800GPT-6.1 Sol
LMArena WebDev: from an image17371702Claude Sonnet 5.5
Neither model has a result on the other 19 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11
Intelligence benchmarks for Claude Sonnet 5.5 and GPT-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 SolLeader
AA Intelligence Index56.051.8Claude Sonnet 5.5
Epoch Capabilities Index166.2168.4GPT-6.1 Sol
Agentic workLike-for-likePublic boards, shown as published, kept out of the index106
Agentic work benchmarks for Claude Sonnet 5.5 and GPT-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 SolLeader
Design Arena: agents building web apps1303Not measuredOnly Claude Sonnet 5.5 measured
Design Arena: agents building mobile apps12651190Claude Sonnet 5.5
Design Arena: spreadsheets12451250GPT-6.1 Sol
LiveBench research83.6%83.5%Claude Sonnet 5.5
LiveBench browser84.0%88.0%GPT-6.1 Sol
LiveBench long agentic78.8%73.0%Claude Sonnet 5.5
SREBench (Vals AI)30.1%50.8%GPT-6.1 Sol
Finance Agent (Vals AI)58.1%52.0%Claude Sonnet 5.5
Tax Agent Bench (Vals AI)42.0%21.8%Claude Sonnet 5.5
Legal Research Bench (Vals AI)48.1%38.5%Claude Sonnet 5.5
Harvey's Legal Agent Benchmark (Vals AI)10.4%6.3%Claude Sonnet 5.5
Excel Modeling Benchmark (Vals AI)75.7%70.8%Claude Sonnet 5.5
BioMysteryBench (Vals AI)81.1%79.6%Claude Sonnet 5.5
Terminal-Bench-Science (Vals AI)47.1%52.9%GPT-6.1 Sol
Vals Science Index59.1%59.6%GPT-6.1 Sol
Robo-bench (Vals AI)Not measured28.3%Only GPT-6.1 Sol measured
APEX-Agents75.5%60.0%Claude Sonnet 5.5
SpireClimb1.3%24.7%GPT-6.1 Sol
Vending-Bench 2$11,165Not measuredOnly Claude Sonnet 5.5 measured
Neither model has a result on the other 20 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index74
Reasoning benchmarks for Claude Sonnet 5.5 and GPT-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 SolLeader
LiveBench reasoning91.6%92.6%GPT-6.1 Sol
MysteryMechanism (Vals AI)49.1%46.4%Claude Sonnet 5.5
Humanity's Last Exam (Artificial Analysis run)55.0%52.9%Claude Sonnet 5.5
GPQA Diamond (Epoch AI run)95.6%95.4%Claude Sonnet 5.5
ARC-AGINot measured98.5%Only GPT-6.1 Sol measured
ARC-AGI-2Not measured94.2%Only GPT-6.1 Sol measured
Chess puzzles59.0%68.0%GPT-6.1 Sol
Mystery game puzzles65.0%80.0%GPT-6.1 Sol
EBR-benchNot measured54.3%Only GPT-6.1 Sol measured
LMArena Text: hard prompts14941463Claude Sonnet 5.5
LMArena Text: expert15311489Claude Sonnet 5.5
LMArena Text: hard prompts in English15021465Claude Sonnet 5.5
LMArena Vision: diagrams13291306Claude Sonnet 5.5
LMArena Vision: homework13311356GPT-6.1 Sol
Neither model has a result on the other 7 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index23
Math benchmarks for Claude Sonnet 5.5 and GPT-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 SolLeader
OTIS Mock AIME100.0%100.0%Tie
FrontierMath, tiers 1 to 388.8%93.7%GPT-6.1 Sol
FrontierMath, tier 480.5%100.0%GPT-6.1 Sol
ProofBench100.0%99.0%Claude Sonnet 5.5
LMArena Text: math14971489Claude Sonnet 5.5
LMArena Text: mathematical work15101513GPT-6.1 Sol
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-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 SolLeader
MedCode (Vals AI)52.9%48.8%Claude Sonnet 5.5
SimpleQA Verified46.5%73.9%GPT-6.1 Sol
LMArena Text: science14831444Claude Sonnet 5.5
LMArena Text: medicine and healthcare14641433Claude Sonnet 5.5
LMArena Text: legal and government14831471Claude Sonnet 5.5
LMArena Text: business and finance14681445Claude Sonnet 5.5
Neither model has a result on the other 11 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index61
Web design benchmarks for Claude Sonnet 5.5 and GPT-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 SolLeader
Design Arena: websites13261321Claude Sonnet 5.5
Design Arena: UI components13671321Claude Sonnet 5.5
Design Arena: game dev14691389Claude Sonnet 5.5
Design Arena: data viz13891278Claude Sonnet 5.5
Design Arena: 3D14581461GPT-6.1 Sol
Design Arena: all code categories13641345Claude Sonnet 5.5
LiveBench design85.0%82.1%Claude Sonnet 5.5
Neither model has a result on the other 2 boards here
GeneralLike-for-likePublic boards, shown as published, kept out of the index206
General benchmarks for Claude Sonnet 5.5 and GPT-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 SolLeader
Vals Index70.8%63.9%Claude Sonnet 5.5
LiveBench data analysis59.5%82.7%GPT-6.1 Sol
Public Benefits Bench (Vals AI)67.2%59.3%Claude Sonnet 5.5
SAGE (Vals AI)51.8%46.5%Claude Sonnet 5.5
MedScribe (Vals AI)91.1%86.5%Claude Sonnet 5.5
Long context reasoning (AA-LCR)82.7%84.0%GPT-6.1 Sol
DTBench97.3%96.5%Claude Sonnet 5.5
LMCA68.3%62.8%Claude Sonnet 5.5
Furniture assembly75.0%80.0%GPT-6.1 Sol
LMArena Text14731443Claude Sonnet 5.5
LMArena Text: instruction following14921466Claude Sonnet 5.5
LMArena Text: creative writing14671425Claude Sonnet 5.5
LMArena Vision12871288GPT-6.1 Sol
LMArena Text: English14841450Claude Sonnet 5.5
LMArena Text: non-English14561433Claude Sonnet 5.5
LMArena Text: Chinese15351487Claude Sonnet 5.5
LMArena Text: French14991460Claude Sonnet 5.5
LMArena Text: Spanish14511439Claude Sonnet 5.5
LMArena Text: Russian14541457GPT-6.1 Sol
LMArena Text: multi-turn14651442Claude Sonnet 5.5
LMArena Text: longer queries14951458Claude Sonnet 5.5
LMArena Text: writing and language14741444Claude Sonnet 5.5
LMArena Text: entertainment and media14611426Claude Sonnet 5.5
LMArena Vision: English12891274Claude Sonnet 5.5
LMArena Vision: reading text12971289Claude Sonnet 5.5
LMArena Vision: creative writing12421301GPT-6.1 Sol
Neither model has a result on the other 20 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-6.1 Sol
BenchmarkClaude Sonnet 5.5GPT-6.1 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-6.1 Sol$0.0070Fits in one request

Same cost

Repository review

50K input + 3K output tokens

Claude Sonnet 5.5$0.130Fits in one request
GPT-6.1 Sol$0.130Fits in one request

Same cost

Agent loop

200K input + 10K output tokens

Claude Sonnet 5.5$0.500Fits in one request
GPT-6.1 Sol$0.500Fits in one request

Same cost

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-6.1 Sol
SpecificationAnthropic Claude Sonnet 5.5OpenAI GPT-6.1 Sol
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 28, 2026September 29, 2026
Context window1M1.05M
Input $/Mtok$2.00$2.00
Output $/Mtok$10.00$10.00
Coding index88.988.7
Independent measurements behind it22
Cost per solved taskNot computableNot computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 5.5 better than GPT-6.1 Sol for coding?

Claude Sonnet 5.5 and GPT-6.1 Sol are level for coding, 88.9 against 88.7 on the Vibe Coding Index, so price and context decide. Pick GPT-6.1 Sol when the context window is larger, 1.05M against 1M tokens, or when what matters is LiveBench coding or IOI (Vals AI), where it leads. Pick Claude Sonnet 5.5 when what matters is LMArena WebDev or Terminal-Bench 4 (Vals AI), where it leads.

Which is cheaper, Claude Sonnet 5.5 or GPT-6.1 Sol?

Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; GPT-6.1 Sol costs $2.00 and $10.00. Cost per solved task is known for neither of them.

Which has the bigger context window, Claude Sonnet 5.5 or GPT-6.1 Sol?

GPT-6.1 Sol, with 1.05M tokens against 1M.

How many benchmarks is the Claude Sonnet 5.5 vs GPT-6.1 Sol comparison based on?

91 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-6.1 Sol's on 2. Where only one model has a result, the page says so instead of naming a winner.

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