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Claude Sonnet 5.5 vs Grok 4.3

Claude Sonnet 5.5 leads Grok 4.3 on coding, 87.3 to 37.4 on the Vibe Coding Index, and Grok 4.3 costs 4.0x less per output token ($2.50 vs $10.00 per million). Updated October 22, 2026; 70 benchmarks have a result for both.

Replace Claude Sonnet 5.5 Replace Grok 4.3
Claude Sonnet 5.5Anthropic
Coding
87.3
Overall
82.8
Output $/M
$10.00
70
Grok 4.3xAI
Coding
37.4
Overall
53.1
Output $/M
$2.50
0
vs boards won of 70 shared

Claude Sonnet 5.5 or Grok 4.3: which to pick

Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 37.4 for Grok 4.3.

Pick Grok 4.3 for output tokens 4.0x cheaper ($2.50 vs $10.00 per million).

Model AClaude Sonnet 5.5Anthropic87.3/1005 independent benchmarksNo cost per solved taskModel BGrok 4.3xAI37.4/1003 independent benchmarks$0.31 per solved task
Shared results
70
Claude Sonnet 5.5 only
26
Grok 4.3 only
35
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 5.5 87.3 from 5 benchmarks, Grok 4.3 37.4 from 3 benchmarks.
Widest category
Math, 40.8 points apart on average over 6 shared benchmarks.
Widest single gap
ProofBench: Claude Sonnet 5.5 100.0% against Grok 4.3 11.0%, 89.0 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 5.5 $10.00 against Grok 4.3 $2.50 per million output tokens, 4.0x apart.
Context window
Both take 1M tokens.

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 5.5BarsGrok 4.3Ties
Coding120
Intelligence10
Agentic work80
Reasoning80
Math60
Knowledge60
Web design60
General230
All shared boards700
CodingLike-for-likeSix of these boards feed the Vibe Coding Index120
Coding benchmarks for Claude Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
LiveBench coding94.7%Not measuredOnly Claude Sonnet 5.5 measured
LMArena WebDev17681358Claude Sonnet 5.5
AA Coding IndexNot measured42.2Only Grok 4.3 measured
LiveCodeBench (Vals AI)Not measured84.5%Only Grok 4.3 measured
SWE-bench Verified (Vals AI)Not measured71.4%Only Grok 4.3 measured
Terminal-Bench 4 (Vals AI)64.1%Not measuredOnly Claude Sonnet 5.5 measured
Vibe Code Bench (Vals AI)92.4%19.4%Claude Sonnet 5.5
Code migration (Vals AI)69.8%6.8%Claude Sonnet 5.5
ProgramBench (Vals AI)6.5%0.0%Claude Sonnet 5.5
IOI (Vals AI)83.1%Not measuredOnly Claude Sonnet 5.5 measured
Terminal-Bench 2.1 (Vals AI)83.2%42.0%Claude Sonnet 5.5
SWE-bench Multimodal (Vals AI)58.3%Not measuredOnly Claude Sonnet 5.5 measured
SkillsBench (Vals AI)Not measured40.6%Only Grok 4.3 measured
CyberBench (Vals AI)59.6%Not measuredOnly Claude Sonnet 5.5 measured
SciCode61.0%48.3%Claude Sonnet 5.5
Terminal-Bench Hard (Artificial Analysis run)Not measured37.9%Only Grok 4.3 measured
FrontierCode52.1%Not measuredOnly Claude Sonnet 5.5 measured
FrontierSWE61.9%Not measuredOnly Claude Sonnet 5.5 measured
WeirdMLNot measured49.9%Only Grok 4.3 measured
ALE-Bench1819.1944.2Claude Sonnet 5.5
LMArena Text: coding15131415Claude Sonnet 5.5
LMArena Text: software and IT15041416Claude Sonnet 5.5
LMArena WebDev: React18171353Claude Sonnet 5.5
LMArena WebDev: HTML17411367Claude Sonnet 5.5
LMArena WebDev: from an image17371375Claude Sonnet 5.5
SciCode13.8%Not measuredOnly Claude Sonnet 5.5 measured
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
Intelligence benchmarks for Claude Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
AA Intelligence Index56.024.9Claude Sonnet 5.5
Epoch Capabilities Index166.2Not measuredOnly Claude Sonnet 5.5 measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index80
Agentic work benchmarks for Claude Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
AA Agentic IndexNot measured15.5Only Grok 4.3 measured
Design Arena: agents building web apps13051126Claude Sonnet 5.5
Design Arena: agents building full-stack appsNot measured1006Only Grok 4.3 measured
Design Arena: agents building mobile apps12601058Claude Sonnet 5.5
Design Arena: agents building Android appsNot measured962Only Grok 4.3 measured
Design Arena: agents building Godot gamesNot measured914Only Grok 4.3 measured
Design Arena: agents building gamesNot measured1007Only Grok 4.3 measured
Design Arena: HTML slidesNot measured959Only Grok 4.3 measured
Design Arena: PowerPoint slidesNot measured988Only Grok 4.3 measured
Design Arena: spreadsheets1260879Claude Sonnet 5.5
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%37.7%Claude Sonnet 5.5
Tax Agent Bench (Vals AI)42.0%6.2%Claude Sonnet 5.5
Legal Research Bench (Vals AI)48.1%15.4%Claude Sonnet 5.5
Harvey's Legal Agent Benchmark (Vals AI)10.4%Not measuredOnly Claude Sonnet 5.5 measured
Excel Modeling Benchmark (Vals AI)75.7%18.4%Claude Sonnet 5.5
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 measured97.7%Only Grok 4.3 measured
APEX-Agents75.5%Not measuredOnly Claude Sonnet 5.5 measured
SpireClimb1.3%Not measuredOnly Claude Sonnet 5.5 measured
Vending-Bench 2$11,165$35Claude Sonnet 5.5
LMArena SearchNot measured1166Only Grok 4.3 measured
Neither model has a result on the other 14 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index80
Reasoning benchmarks for Claude Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
GPQA DiamondNot measured91.4%Only Grok 4.3 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 measured83.1%Only Grok 4.3 measured
GPQA Diamond (Artificial Analysis run)Not measured90.1%Only Grok 4.3 measured
Humanity's Last Exam (Artificial Analysis run)55.0%37.2%Claude Sonnet 5.5
GPQA Diamond (Epoch AI run)95.6%88.8%Claude Sonnet 5.5
Chess puzzles59.0%18.0%Claude Sonnet 5.5
Mystery game puzzles65.0%Not measuredOnly Claude Sonnet 5.5 measured
LMArena Text: hard prompts14941396Claude Sonnet 5.5
LMArena Text: expert15311384Claude Sonnet 5.5
LMArena Text: hard prompts in English15021402Claude Sonnet 5.5
LMArena Vision: diagrams13291241Claude Sonnet 5.5
LMArena Vision: homework13311241Claude Sonnet 5.5
Neither model has a result on the other 8 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for Claude Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
OTIS Mock AIME100.0%93.3%Claude Sonnet 5.5
FrontierMath, tiers 1 to 388.8%42.8%Claude Sonnet 5.5
FrontierMath, tier 480.5%14.6%Claude Sonnet 5.5
ProofBench100.0%11.0%Claude Sonnet 5.5
LMArena Text: math14971387Claude Sonnet 5.5
LMArena Text: mathematical work15101396Claude 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 index60
Knowledge benchmarks for Claude Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
MMLU ProNot measured85.8%Only Grok 4.3 measured
LegalBench (Vals AI)Not measured84.5%Only Grok 4.3 measured
CaseLaw (Vals AI)Not measured79.3%Only Grok 4.3 measured
CorpFin (Vals AI)Not measured68.5%Only Grok 4.3 measured
TaxEval (Vals AI)Not measured70.8%Only Grok 4.3 measured
MortgageTax (Vals AI)Not measured48.3%Only Grok 4.3 measured
MedCode (Vals AI)52.9%38.1%Claude Sonnet 5.5
SimpleQA Verified46.5%33.2%Claude Sonnet 5.5
LMArena Text: science14831399Claude Sonnet 5.5
LMArena Text: medicine and healthcare14641384Claude Sonnet 5.5
LMArena Text: legal and government14831386Claude Sonnet 5.5
LMArena Text: business and finance14681381Claude 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 index60
Web design benchmarks for Claude Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
Design Arena: websites13261196Claude Sonnet 5.5
Design Arena: UI components13681190Claude Sonnet 5.5
Design Arena: game dev14711173Claude Sonnet 5.5
Design Arena: data viz13921179Claude Sonnet 5.5
Design Arena: 3D14451124Claude Sonnet 5.5
Design Arena: all code categories13641186Claude Sonnet 5.5
Design Arena: SVGNot measured1080Only Grok 4.3 measured
Design Arena: ASCII artNot measured1125Only Grok 4.3 measured
LiveBench design85.0%Not measuredOnly Claude Sonnet 5.5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index230
General benchmarks for Claude Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
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%51.7%Claude Sonnet 5.5
SAGE (Vals AI)51.8%19.7%Claude Sonnet 5.5
MedScribe (Vals AI)91.1%74.4%Claude Sonnet 5.5
Vals Multimodal IndexNot measured43.3%Only Grok 4.3 measured
IFBenchNot measured83.3%Only Grok 4.3 measured
Long context reasoning (AA-LCR)82.7%75.0%Claude Sonnet 5.5
DTBench97.3%90.7%Claude Sonnet 5.5
LMCA68.3%38.3%Claude Sonnet 5.5
Furniture assembly75.0%Not measuredOnly Claude Sonnet 5.5 measured
LMArena Text14731397Claude Sonnet 5.5
LMArena Text: instruction following14921366Claude Sonnet 5.5
LMArena Text: creative writing14671380Claude Sonnet 5.5
LMArena Vision12871229Claude Sonnet 5.5
LMArena Text: English14841404Claude Sonnet 5.5
LMArena Text: non-English14561385Claude Sonnet 5.5
LMArena Text: Chinese15351422Claude Sonnet 5.5
LMArena Text: GermanNot measured1395Only Grok 4.3 measured
LMArena Text: JapaneseNot measured1379Only Grok 4.3 measured
LMArena Text: KoreanNot measured1354Only Grok 4.3 measured
LMArena Text: French14991411Claude Sonnet 5.5
LMArena Text: Spanish14511399Claude Sonnet 5.5
LMArena Text: Russian14541399Claude Sonnet 5.5
LMArena Text: PolishNot measured1398Only Grok 4.3 measured
LMArena Text: multi-turn14651406Claude Sonnet 5.5
LMArena Text: longer queries14951393Claude Sonnet 5.5
LMArena Text: writing and language14741385Claude Sonnet 5.5
LMArena Text: entertainment and media14611370Claude Sonnet 5.5
LMArena Vision: English12891235Claude Sonnet 5.5
LMArena Vision: ChineseNot measured1257Only Grok 4.3 measured
LMArena Vision: reading text12971235Claude Sonnet 5.5
LMArena Vision: humorNot measured1222Only Grok 4.3 measured
LMArena Vision: recognizing thingsNot measured1217Only Grok 4.3 measured
LMArena Vision: creative writing12421237Claude Sonnet 5.5
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 Sonnet 5.5 and Grok 4.3
BenchmarkClaude Sonnet 5.5Grok 4.3Leader
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
Grok 4.3$0.0025Fits in one request

Grok 4.3 costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 5.5$0.130Fits in one request
Grok 4.3$0.070Fits in one request

Grok 4.3 costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 5.5$0.500Fits in one request
Grok 4.3$0.275Fits in one request

Grok 4.3 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 Grok 4.3
SpecificationAnthropic Claude Sonnet 5.5SpaceXAI Grok 4.3
MakerAnthropicxAI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 28, 2026April 30, 2026
Context window1M1M
Input $/Mtok$2.00$1.25
Output $/Mtok$10.00$2.50
Coding index87.337.4
Independent measurements behind it53
Cost per solved taskNot computable$0.31
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 5.5 better than Grok 4.3 for coding?

Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 37.4 for Grok 4.3. Pick Grok 4.3 for output tokens 4.0x cheaper ($2.50 vs $10.00 per million).

Which is cheaper, Claude Sonnet 5.5 or Grok 4.3?

Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; Grok 4.3 costs $1.25 and $2.50. Cost per solved task is known for Grok 4.3 only.

Which has the bigger context window, Claude Sonnet 5.5 or Grok 4.3?

Neither: both take 1M tokens.

How many benchmarks is the Claude Sonnet 5.5 vs Grok 4.3 comparison based on?

70 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 5.5's coding index rests on 5 independent benchmarks and Grok 4.3's on 3. Where only one model has a result, the page says so instead of naming a winner.

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<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/claude-sonnet-5-5-vs-grok-4-3">LLMBenchmark.ai, Claude Sonnet 5.5 vs Grok 4.3</a></p>