LLMBenchmark.ai

Enter opens the highlighted result. Esc closes.

Claude Sonnet 5.5 vs GPT-5.1

Updated October 21, 2026. 56 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-5.1
Claude Sonnet 5.5Anthropic
Coding
88.9
Overall
56.0
Output $/M
$10.00
54
GPT-5.1OpenAI
Coding
53.3
Overall
24.7
Output $/M
$10.00
2
vs boards won of 56 shared

Decision reading

Pick Claude Sonnet 5.5 for coding: it scores 88.9 on the Vibe Coding Index against 53.3 for GPT-5.1.

Pick GPT-5.1 when what matters is SimpleQA Verified or LMArena Vision: creative writing, where it leads.

Model AClaude Sonnet 5.5Anthropic88.9/1002 independent benchmarksNo cost per solved taskModel BGPT-5.1OpenAI53.3/1002 independent benchmarks$1.02 per solved task
Shared results
56
Claude Sonnet 5.5 only
39
GPT-5.1 only
44
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-5.1 53.3 from 2 benchmarks.
Widest category
Agentic work, 60.6 points apart on average over 1 shared benchmark.
Widest single gap
Vibe Code Bench (Vals AI): Claude Sonnet 5.5 92.4% against GPT-5.1 24.6%, 67.8 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-5.1 400K.

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-5.1Ties
Coding70
Intelligence20
Agentic work10
Reasoning90
Math30
Knowledge51
Web design60
General211
All shared boards542
CodingLike-for-likeFour of these boards feed the Vibe Coding Index70
Coding benchmarks for Claude Sonnet 5.5 and GPT-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
SWE-bench VerifiedNot measured66.0%Only GPT-5.1 measured
LiveBench coding94.7%Not measuredOnly Claude Sonnet 5.5 measured
LMArena WebDev17681396Claude Sonnet 5.5
AA Coding IndexNot measured49.4Only GPT-5.1 measured
LiveCodeBench (Vals AI)Not measured86.5%Only GPT-5.1 measured
SWE-bench Verified (Vals AI)Not measured69.8%Only GPT-5.1 measured
Terminal-Bench 4 (Vals AI)64.1%Not measuredOnly Claude Sonnet 5.5 measured
Vibe Code Bench (Vals AI)92.4%24.6%Claude Sonnet 5.5
Code migration (Vals AI)69.8%Not measuredOnly Claude Sonnet 5.5 measured
ProgramBench (Vals AI)6.5%Not measuredOnly Claude Sonnet 5.5 measured
IOI (Vals AI)83.1%Not measuredOnly Claude Sonnet 5.5 measured
Terminal-Bench 2.1 (Vals AI)83.2%Not measuredOnly Claude Sonnet 5.5 measured
SWE-bench Multimodal (Vals AI)58.3%Not measuredOnly Claude Sonnet 5.5 measured
CyberBench (Vals AI)59.6%Not measuredOnly Claude Sonnet 5.5 measured
LiveCodeBench (Artificial Analysis run)Not measured86.8%Only GPT-5.1 measured
SciCode61.0%Not measuredOnly Claude Sonnet 5.5 measured
Terminal-Bench Hard (Artificial Analysis run)Not measured45.5%Only GPT-5.1 measured
Terminal-BenchNot measured47.6%Only GPT-5.1 measured
FrontierCode52.1%Not measuredOnly Claude Sonnet 5.5 measured
FrontierSWE61.9%Not measuredOnly Claude Sonnet 5.5 measured
GSO-BenchNot measured13.7%Only GPT-5.1 measured
WeirdMLNot measured60.8%Only GPT-5.1 measured
ALE-Bench1819.1Not measuredOnly Claude Sonnet 5.5 measured
LMArena Text: coding15131453Claude Sonnet 5.5
LMArena Text: software and IT15041454Claude Sonnet 5.5
LMArena WebDev: React18171307Claude Sonnet 5.5
LMArena WebDev: HTML17411405Claude Sonnet 5.5
LMArena WebDev: from an image17371421Claude 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-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
AA Intelligence Index56.024.7Claude Sonnet 5.5
Epoch Capabilities Index166.2149.8Claude Sonnet 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
Agentic work benchmarks for Claude Sonnet 5.5 and GPT-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
Design Arena: agents building web apps1303Not measuredOnly Claude Sonnet 5.5 measured
Design Arena: agents building mobile apps1265Not measuredOnly Claude Sonnet 5.5 measured
Design Arena: spreadsheets1245Not measuredOnly Claude Sonnet 5.5 measured
LiveBench research83.6%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench browser84.0%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench long agentic78.8%Not measuredOnly Claude Sonnet 5.5 measured
SREBench (Vals AI)30.1%Not measuredOnly Claude Sonnet 5.5 measured
Finance Agent (Vals AI)58.1%Not measuredOnly Claude Sonnet 5.5 measured
Tax Agent Bench (Vals AI)42.0%Not measuredOnly Claude Sonnet 5.5 measured
Legal Research Bench (Vals AI)48.1%Not measuredOnly Claude Sonnet 5.5 measured
Harvey's Legal Agent Benchmark (Vals AI)10.4%Not measuredOnly Claude Sonnet 5.5 measured
Excel Modeling Benchmark (Vals AI)75.7%Not measuredOnly Claude Sonnet 5.5 measured
BioMysteryBench (Vals AI)81.1%Not measuredOnly Claude Sonnet 5.5 measured
Terminal-Bench-Science (Vals AI)47.1%Not measuredOnly Claude Sonnet 5.5 measured
Vals Science Index59.1%Not measuredOnly Claude Sonnet 5.5 measured
τ²-Bench TelecomNot measured81.9%Only GPT-5.1 measured
APEX-Agents75.5%Not measuredOnly Claude Sonnet 5.5 measured
DeepResearch BenchNot measured42.8%Only GPT-5.1 measured
SpireClimb1.3%Not measuredOnly Claude Sonnet 5.5 measured
Vending-Bench 2$11,165$1,473Claude Sonnet 5.5
Neither model has a result on the other 19 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
Reasoning benchmarks for Claude Sonnet 5.5 and GPT-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
GPQA DiamondNot measured86.6%Only GPT-5.1 measured
LiveBench reasoning91.6%Not measuredOnly Claude Sonnet 5.5 measured
MysteryMechanism (Vals AI)49.1%Not measuredOnly Claude Sonnet 5.5 measured
MMMU Pro (Vals AI)Not measured83.2%Only GPT-5.1 measured
GPQA Diamond (Artificial Analysis run)Not measured87.3%Only GPT-5.1 measured
Humanity's Last Exam (Artificial Analysis run)55.0%28.5%Claude Sonnet 5.5
GPQA Diamond (Epoch AI run)95.6%87.6%Claude Sonnet 5.5
ARC-AGINot measured72.8%Only GPT-5.1 measured
ARC-AGI-2Not measured17.6%Only GPT-5.1 measured
SimpleBenchNot measured53.2%Only GPT-5.1 measured
Chess puzzles59.0%42.0%Claude Sonnet 5.5
Mystery game puzzles65.0%19.0%Claude Sonnet 5.5
VPCTNot measured58.7%Only GPT-5.1 measured
LMArena Text: hard prompts14941457Claude Sonnet 5.5
LMArena Text: expert15311470Claude Sonnet 5.5
LMArena Text: hard prompts in English15021462Claude Sonnet 5.5
LMArena Vision: diagrams13291264Claude Sonnet 5.5
LMArena Vision: homework13311272Claude 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 index30
Math benchmarks for Claude Sonnet 5.5 and GPT-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
AIMENot measured93.3%Only GPT-5.1 measured
MGSM (Vals AI)Not measured93.0%Only GPT-5.1 measured
AA Math IndexNot measured94.0Only GPT-5.1 measured
AIME 2025 (Artificial Analysis run)Not measured94.0%Only GPT-5.1 measured
OTIS Mock AIME100.0%88.6%Claude Sonnet 5.5
FrontierMath, tiers 1 to 388.8%Not measuredOnly Claude Sonnet 5.5 measured
FrontierMath, tier 480.5%Not measuredOnly Claude Sonnet 5.5 measured
ProofBench100.0%Not measuredOnly Claude Sonnet 5.5 measured
LMArena Text: math14971446Claude Sonnet 5.5
LMArena Text: mathematical work15101449Claude Sonnet 5.5
Neither model has a result on the other 3 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index51
Knowledge benchmarks for Claude Sonnet 5.5 and GPT-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
MMLU ProNot measured86.4%Only GPT-5.1 measured
LegalBench (Vals AI)Not measured85.7%Only GPT-5.1 measured
CaseLaw (Vals AI)Not measured73.4%Only GPT-5.1 measured
CorpFin (Vals AI)Not measured63.8%Only GPT-5.1 measured
TaxEval (Vals AI)Not measured74.9%Only GPT-5.1 measured
MortgageTax (Vals AI)Not measured61.4%Only GPT-5.1 measured
MedQA (Vals AI)Not measured96.4%Only GPT-5.1 measured
MedCode (Vals AI)52.9%52.7%Claude Sonnet 5.5
MMLU Pro (Artificial Analysis run)Not measured87.0%Only GPT-5.1 measured
SimpleQA Verified46.5%48.0%GPT-5.1
LMArena Text: science14831459Claude Sonnet 5.5
LMArena Text: medicine and healthcare14641456Claude Sonnet 5.5
LMArena Text: legal and government14831459Claude Sonnet 5.5
LMArena Text: business and finance14681431Claude Sonnet 5.5
Neither model has a result on the other 3 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index60
Web design benchmarks for Claude Sonnet 5.5 and GPT-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
Design Arena: websites13261187Claude Sonnet 5.5
Design Arena: UI components13671166Claude Sonnet 5.5
Design Arena: game dev14691179Claude Sonnet 5.5
Design Arena: data viz13891204Claude Sonnet 5.5
Design Arena: 3D14581061Claude Sonnet 5.5
Design Arena: all code categories13641171Claude Sonnet 5.5
Design Arena: SVGNot measured1149Only GPT-5.1 measured
Design Arena: ASCII artNot measured1118Only GPT-5.1 measured
LiveBench design85.0%Not measuredOnly Claude Sonnet 5.5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index211
General benchmarks for Claude Sonnet 5.5 and GPT-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
Vals Index70.8%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench data analysis59.5%Not measuredOnly Claude Sonnet 5.5 measured
Public Benefits Bench (Vals AI)67.2%Not measuredOnly Claude Sonnet 5.5 measured
SAGE (Vals AI)51.8%43.2%Claude Sonnet 5.5
MedScribe (Vals AI)91.1%88.1%Claude Sonnet 5.5
IFBenchNot measured72.9%Only GPT-5.1 measured
Long context reasoning (AA-LCR)82.7%80.0%Claude Sonnet 5.5
DTBench97.3%90.1%Claude Sonnet 5.5
LMCA68.3%43.9%Claude Sonnet 5.5
CL-benchNot measured23.7%Only GPT-5.1 measured
Furniture assembly75.0%Not measuredOnly Claude Sonnet 5.5 measured
CL-bench LifeNot measured17.3%Only GPT-5.1 measured
LMArena Text14731443Claude Sonnet 5.5
LMArena Text: instruction following14921443Claude Sonnet 5.5
LMArena Text: creative writing14671427Claude Sonnet 5.5
LMArena Vision12871250Claude Sonnet 5.5
LMArena Text: English14841451Claude Sonnet 5.5
LMArena Text: non-English14561431Claude Sonnet 5.5
LMArena Text: Chinese15351495Claude Sonnet 5.5
LMArena Text: GermanNot measured1438Only GPT-5.1 measured
LMArena Text: JapaneseNot measured1453Only GPT-5.1 measured
LMArena Text: KoreanNot measured1401Only GPT-5.1 measured
LMArena Text: French14991450Claude Sonnet 5.5
LMArena Text: Spanish14511433Claude Sonnet 5.5
LMArena Text: Russian14541435Claude Sonnet 5.5
LMArena Text: PolishNot measured1440Only GPT-5.1 measured
LMArena Text: multi-turn14651450Claude Sonnet 5.5
LMArena Text: longer queries14951448Claude Sonnet 5.5
LMArena Text: writing and language14741428Claude Sonnet 5.5
LMArena Text: entertainment and media14611415Claude Sonnet 5.5
LMArena Vision: English12891252Claude Sonnet 5.5
LMArena Vision: ChineseNot measured1270Only GPT-5.1 measured
LMArena Vision: reading text12971255Claude Sonnet 5.5
LMArena Vision: humorNot measured1263Only GPT-5.1 measured
LMArena Vision: captioningNot measured1252Only GPT-5.1 measured
LMArena Vision: recognizing thingsNot measured1232Only GPT-5.1 measured
LMArena Vision: creative writing12421266GPT-5.1
LMArena DocumentNot measured1403Only GPT-5.1 measured
Neither model has a result on the other 8 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-5.1
BenchmarkClaude Sonnet 5.5GPT-5.1Leader
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-5.1$0.0063Fits in one request

GPT-5.1 costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 5.5$0.130Fits in one request
GPT-5.1$0.092Fits in one request

GPT-5.1 costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 5.5$0.500Fits in one request
GPT-5.1$0.350Fits in one request

GPT-5.1 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-5.1
SpecificationAnthropic Claude Sonnet 5.5OpenAI GPT-5.1
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 28, 2026November 13, 2025
Context window1M400K
Input $/Mtok$2.00$1.25
Output $/Mtok$10.00$10.00
Coding index88.953.3
Independent measurements behind it22
Cost per solved taskNot computable$1.02
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 5.5 better than GPT-5.1 for coding?

Pick Claude Sonnet 5.5 for coding: it scores 88.9 on the Vibe Coding Index against 53.3 for GPT-5.1. Pick GPT-5.1 when what matters is SimpleQA Verified or LMArena Vision: creative writing, where it leads.

Which is cheaper, Claude Sonnet 5.5 or GPT-5.1?

Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; GPT-5.1 costs $1.25 and $10.00. Cost per solved task is known for GPT-5.1 only.

Which has the bigger context window, Claude Sonnet 5.5 or GPT-5.1?

Claude Sonnet 5.5, with 1M tokens against 400K.

How many benchmarks is the Claude Sonnet 5.5 vs GPT-5.1 comparison based on?

56 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-5.1's on 2. Where only one model has a result, the page says so instead of naming a winner.

Compare next

Embed this comparison on your site

Free under CC BY 4.0, while the source link stays visible. Preview the frame · Terms and other embeds

<iframe src="https://llmbenchmark.ai/embed/compare/claude-sonnet-5-5-vs-gpt-5-1" title="Claude Sonnet 5.5 vs GPT-5.1, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/claude-sonnet-5-5-vs-gpt-5-1">LLMBenchmark.ai, Claude Sonnet 5.5 vs GPT-5.1</a></p>