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Claude Sonnet 5.5 vs Grok 4.5

Claude Sonnet 5.5 leads Grok 4.5 on coding, 87.3 to 58.6 on the Vibe Coding Index, and Grok 4.5 costs 1.7x less per output token ($6.00 vs $10.00 per million). Updated October 22, 2026; 84 benchmarks have a result for both.

Replace Claude Sonnet 5.5 Replace Grok 4.5
Claude Sonnet 5.5Anthropic
Coding
87.3
Overall
82.8
Output $/M
$10.00
78
Grok 4.5xAI
Coding
58.6
Overall
62.1
Output $/M
$6.00
6
vs boards won of 84 shared

Claude Sonnet 5.5 or Grok 4.5: which to pick

Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 58.6 for Grok 4.5, though on 5 benchmarks against 6.

Pick Grok 4.5 for output tokens 1.7x cheaper ($6.00 vs $10.00 per million) and work measured by CyberBench (Vals AI) or LiveBench research, where it leads.

Model AClaude Sonnet 5.5Anthropic87.3/1005 independent benchmarksNo cost per solved taskModel BGrok 4.5xAI58.6/1006 independent benchmarks$0.62 per solved task
Shared results
84
Claude Sonnet 5.5 only
12
Grok 4.5 only
39
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 4.5 58.6 from 6 benchmarks.
Widest category
Math, 28.3 points apart on average over 6 shared benchmarks.
Widest single gap
Terminal-Bench 4 (Vals AI): Claude Sonnet 5.5 64.1% against Grok 4.5 8.6%, 74.1 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 5.5 $10.00 against Grok 4.5 $6.00 per million output tokens, 1.7x apart.
Context window
Claude Sonnet 5.5 takes 1M tokens, Grok 4.5 500K.

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 4.5Ties
Coding171
Intelligence20
Agentic work111
Reasoning90
Math60
Knowledge51
Web design70
General213
All shared boards786
CodingLike-for-likeSix of these boards feed the Vibe Coding Index171
Coding benchmarks for Claude Sonnet 5.5 and Grok 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
LiveBench coding94.7%94.3%Claude Sonnet 5.5
LMArena WebDev17681553Claude Sonnet 5.5
AA Coding IndexNot measured72.4Only Grok 4.5 measured
LiveCodeBench (Vals AI)Not measured87.3%Only Grok 4.5 measured
SWE-bench Verified (Vals AI)Not measured86.6%Only Grok 4.5 measured
Terminal-Bench 4 (Vals AI)64.1%8.6%Claude Sonnet 5.5
Vibe Code Bench (Vals AI)92.4%69.0%Claude Sonnet 5.5
Code migration (Vals AI)69.8%36.6%Claude Sonnet 5.5
ProgramBench (Vals AI)6.5%0.0%Claude Sonnet 5.5
IOI (Vals AI)83.1%40.6%Claude Sonnet 5.5
Terminal-Bench 2.1 (Vals AI)83.2%67.8%Claude Sonnet 5.5
SWE-bench Multimodal (Vals AI)58.3%Not measuredOnly Claude Sonnet 5.5 measured
SkillsBench (Vals AI)Not measured66.0%Only Grok 4.5 measured
CyberBench (Vals AI)59.6%71.0%Grok 4.5
SciCode61.0%55.0%Claude Sonnet 5.5
FrontierCode52.1%42.4%Claude Sonnet 5.5
FrontierSWE61.9%Not measuredOnly Claude Sonnet 5.5 measured
WeirdMLNot measured46.4%Only Grok 4.5 measured
ALE-Bench1819.11309.3Claude Sonnet 5.5
LMArena Text: coding15131474Claude Sonnet 5.5
LMArena Text: software and IT15041471Claude Sonnet 5.5
LMArena WebDev: React18171556Claude Sonnet 5.5
LMArena WebDev: HTML17411567Claude Sonnet 5.5
LMArena WebDev: from an image17371562Claude Sonnet 5.5
SciCode13.8%6.5%Claude Sonnet 5.5
Neither model has a result on the other 14 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Sonnet 5.5 and Grok 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
AA Intelligence Index56.038.8Claude Sonnet 5.5
Epoch Capabilities Index166.2154.1Claude Sonnet 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index111
Agentic work benchmarks for Claude Sonnet 5.5 and Grok 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
AA Agentic IndexNot measured41.2Only Grok 4.5 measured
Design Arena: agents building web apps13051218Claude Sonnet 5.5
Design Arena: agents building full-stack appsNot measured1249Only Grok 4.5 measured
Design Arena: agents building mobile apps12601220Claude Sonnet 5.5
Design Arena: agents building Android appsNot measured1236Only Grok 4.5 measured
Design Arena: agents building Godot gamesNot measured1229Only Grok 4.5 measured
Design Arena: agents building gamesNot measured1236Only Grok 4.5 measured
Design Arena: HTML slidesNot measured1205Only Grok 4.5 measured
Design Arena: PowerPoint slidesNot measured1230Only Grok 4.5 measured
Design Arena: spreadsheets1260Not measuredOnly Claude Sonnet 5.5 measured
LiveBench research83.6%85.9%Grok 4.5
LiveBench browser84.0%44.0%Claude Sonnet 5.5
LiveBench long agentic78.8%27.9%Claude Sonnet 5.5
SREBench (Vals AI)30.1%0.8%Claude Sonnet 5.5
Finance Agent (Vals AI)58.1%48.4%Claude Sonnet 5.5
Tax Agent Bench (Vals AI)42.0%24.9%Claude Sonnet 5.5
Legal Research Bench (Vals AI)48.1%38.0%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%52.9%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
Time Horizon Index (Vals AI)Not measured6.3%Only Grok 4.5 measured
APEX-Agents75.5%56.2%Claude Sonnet 5.5
PostTrainBenchNot measured23.4%Only Grok 4.5 measured
SpireClimb1.3%Not measuredOnly Claude Sonnet 5.5 measured
Vending-Bench 2$11,165$3,887Claude Sonnet 5.5
LMArena SearchNot measured1216Only Grok 4.5 measured
Neither model has a result on the other 13 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
Reasoning benchmarks for Claude Sonnet 5.5 and Grok 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
GPQA DiamondNot measured92.9%Only Grok 4.5 measured
LiveBench reasoning91.6%87.2%Claude Sonnet 5.5
MysteryMechanism (Vals AI)49.1%Not measuredOnly Claude Sonnet 5.5 measured
MMMU Pro (Vals AI)Not measured61.8%Only Grok 4.5 measured
GPQA Diamond (Artificial Analysis run)Not measured93.1%Only Grok 4.5 measured
Humanity's Last Exam (Artificial Analysis run)55.0%42.7%Claude Sonnet 5.5
GPQA Diamond (Epoch AI run)95.6%93.4%Claude Sonnet 5.5
ARC-AGINot measured87.2%Only Grok 4.5 measured
ARC-AGI-2Not measured52.6%Only Grok 4.5 measured
SimpleBenchNot measured70.0%Only Grok 4.5 measured
Chess puzzles59.0%35.0%Claude Sonnet 5.5
Mystery game puzzles65.0%Not measuredOnly Claude Sonnet 5.5 measured
LMArena Text: hard prompts14941462Claude Sonnet 5.5
LMArena Text: expert15311465Claude Sonnet 5.5
LMArena Text: hard prompts in English15021464Claude Sonnet 5.5
LMArena Vision: diagrams13291304Claude Sonnet 5.5
LMArena Vision: homework13311295Claude Sonnet 5.5
Kagi LLM BenchmarkNot measured83.5%Only Grok 4.5 measured
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for Claude Sonnet 5.5 and Grok 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
OTIS Mock AIME100.0%97.8%Claude Sonnet 5.5
FrontierMath, tiers 1 to 388.8%57.2%Claude Sonnet 5.5
FrontierMath, tier 480.5%24.4%Claude Sonnet 5.5
ProofBench100.0%31.0%Claude Sonnet 5.5
LMArena Text: math14971460Claude Sonnet 5.5
LMArena Text: mathematical work15101482Claude 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 Grok 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
MMLU ProNot measured89.2%Only Grok 4.5 measured
LegalBench (Vals AI)Not measured86.0%Only Grok 4.5 measured
CorpFin (Vals AI)Not measured67.4%Only Grok 4.5 measured
TaxEval (Vals AI)Not measured71.7%Only Grok 4.5 measured
MortgageTax (Vals AI)Not measured61.8%Only Grok 4.5 measured
MedCode (Vals AI)52.9%43.3%Claude Sonnet 5.5
SimpleQA Verified46.5%48.3%Grok 4.5
LMArena Text: science14831464Claude Sonnet 5.5
LMArena Text: medicine and healthcare14641440Claude Sonnet 5.5
LMArena Text: legal and government14831463Claude Sonnet 5.5
LMArena Text: business and finance14681441Claude Sonnet 5.5
FACTS Benchmark SuiteNot measured50.2%Only Grok 4.5 measured
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 Grok 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
Design Arena: websites13261281Claude Sonnet 5.5
Design Arena: UI components13681280Claude Sonnet 5.5
Design Arena: game dev14711264Claude Sonnet 5.5
Design Arena: data viz13921266Claude Sonnet 5.5
Design Arena: 3D14451257Claude Sonnet 5.5
Design Arena: all code categories13641275Claude Sonnet 5.5
Design Arena: SVGNot measured1215Only Grok 4.5 measured
Design Arena: ASCII artNot measured1256Only Grok 4.5 measured
LiveBench design85.0%78.1%Claude Sonnet 5.5
GeneralLike-for-likePublic boards, shown as published, kept out of the index213
General benchmarks for Claude Sonnet 5.5 and Grok 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
Vals Index70.8%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench data analysis59.5%73.0%Grok 4.5
Public Benefits Bench (Vals AI)67.2%Not measuredOnly Claude Sonnet 5.5 measured
SAGE (Vals AI)51.8%35.0%Claude Sonnet 5.5
MedScribe (Vals AI)91.1%86.9%Claude Sonnet 5.5
Vals Multimodal IndexNot measured63.4%Only Grok 4.5 measured
Long context reasoning (AA-LCR)82.7%79.3%Claude Sonnet 5.5
DTBench97.3%96.5%Claude Sonnet 5.5
LMCA68.3%45.2%Claude Sonnet 5.5
Surface Evolver BenchNot measured74.4%Only Grok 4.5 measured
Furniture assembly75.0%22.5%Claude Sonnet 5.5
LMArena Text14731448Claude Sonnet 5.5
LMArena Text: instruction following14921445Claude Sonnet 5.5
LMArena Text: creative writing14671442Claude Sonnet 5.5
LMArena Vision12871287Claude Sonnet 5.5
LMArena Text: English14841453Claude Sonnet 5.5
LMArena Text: non-English14561440Claude Sonnet 5.5
LMArena Text: Chinese15351495Claude Sonnet 5.5
LMArena Text: GermanNot measured1448Only Grok 4.5 measured
LMArena Text: JapaneseNot measured1430Only Grok 4.5 measured
LMArena Text: KoreanNot measured1406Only Grok 4.5 measured
LMArena Text: French14991457Claude Sonnet 5.5
LMArena Text: Spanish14511451Grok 4.5
LMArena Text: Russian14541449Claude Sonnet 5.5
LMArena Text: PolishNot measured1432Only Grok 4.5 measured
LMArena Text: multi-turn14651456Claude Sonnet 5.5
LMArena Text: longer queries14951462Claude Sonnet 5.5
LMArena Text: writing and language14741445Claude Sonnet 5.5
LMArena Text: entertainment and media14611434Claude Sonnet 5.5
LMArena Vision: English12891285Claude Sonnet 5.5
LMArena Vision: ChineseNot measured1345Only Grok 4.5 measured
LMArena Vision: reading text12971293Claude Sonnet 5.5
LMArena Vision: humorNot measured1276Only Grok 4.5 measured
LMArena Vision: creative writing12421293Grok 4.5
LMArena DocumentNot measured1452Only Grok 4.5 measured
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 4.5
BenchmarkClaude Sonnet 5.5Grok 4.5Leader
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 4.5$0.0050Fits in one request

Grok 4.5 costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 5.5$0.130Fits in one request
Grok 4.5$0.118Fits in one request

Grok 4.5 costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 5.5$0.500Fits in one request
Grok 4.5$0.460Fits in one request

Grok 4.5 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 Grok 4.5
SpecificationAnthropic Claude Sonnet 5.5SpaceXAI Grok 4.5
MakerAnthropicxAI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 28, 2026July 8, 2026
Context window1M500K
Input $/Mtok$2.00$2.00
Output $/Mtok$10.00$6.00
Coding index87.358.6
Independent measurements behind it56
Cost per solved taskNot computable$0.62
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 5.5 better than Grok 4.5 for coding?

Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 58.6 for Grok 4.5, though on 5 benchmarks against 6. Pick Grok 4.5 for output tokens 1.7x cheaper ($6.00 vs $10.00 per million) and work measured by CyberBench (Vals AI) or LiveBench research, where it leads.

Which is cheaper, Claude Sonnet 5.5 or Grok 4.5?

Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; Grok 4.5 costs $2.00 and $6.00. Cost per solved task is known for Grok 4.5 only.

Which has the bigger context window, Claude Sonnet 5.5 or Grok 4.5?

Claude Sonnet 5.5, with 1M tokens against 500K.

How many benchmarks is the Claude Sonnet 5.5 vs Grok 4.5 comparison based on?

84 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 4.5's on 6. Where only one model has a result, the page says so instead of naming a winner.

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