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Claude Sonnet 4.5 vs GLM 5.3 Flash

GLM 5.3 Flash leads Claude Sonnet 4.5 on coding, 57.7 to 39.5 on the Vibe Coding Index, and GLM 5.3 Flash costs 30.0x less per output token ($0.50 vs $15.00 per million). Updated October 22, 2026; 61 benchmarks have a result for both.

Replace Claude Sonnet 4.5 Replace GLM 5.3 Flash
Claude Sonnet 4.5Anthropic
Coding
39.5
Overall
49.5
Output $/M
$15.00
4
GLM 5.3 FlashZ.ai
Coding
57.7
Overall
66.0
Output $/M
$0.50
57
vs boards won of 61 shared

Claude Sonnet 4.5 or GLM 5.3 Flash: which to pick

Pick GLM 5.3 Flash for coding: it scores 57.7 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5.

Pick Claude Sonnet 4.5 for work measured by Mystery game puzzles or MMLU Pro, where it leads.

Model AClaude Sonnet 4.5Anthropic39.5/1003 independent benchmarks$1.16 per solved taskModel BGLM 5.3 FlashZ.ai57.7/1006 independent benchmarks$0.02 per solved task
Shared results
61
Claude Sonnet 4.5 only
34
GLM 5.3 Flash only
41
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 4.5 39.5 from 3 benchmarks, GLM 5.3 Flash 57.7 from 6 benchmarks.
Widest category
Agentic work, 35.1 points apart on average over 1 shared benchmark.
Widest single gap
ARC-AGI-2: Claude Sonnet 4.5 13.6% against GLM 5.3 Flash 65.8%, 52.2 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 4.5 $15.00 against GLM 5.3 Flash $0.50 per million output tokens, 30.0x apart.
Context window
Claude Sonnet 4.5 takes 1M tokens, GLM 5.3 Flash 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 4.5BarsGLM 5.3 FlashTies
Coding09
Intelligence02
Agentic work01
Reasoning19
Math06
Knowledge25
Web design08
General117
All shared boards457
CodingLike-for-likeSix of these boards feed the Vibe Coding Index09
Coding benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
SWE-bench Verified74.8%Not measuredOnly Claude Sonnet 4.5 measured
SWE-bench Multilingual67.0%Not measuredOnly Claude Sonnet 4.5 measured
LiveBench codingNot measured80.6%Only GLM 5.3 Flash measured
LMArena WebDev13941607GLM 5.3 Flash
AA Coding Index52.171.5GLM 5.3 Flash
LiveCodeBench (Vals AI)73.0%80.5%GLM 5.3 Flash
SWE-bench Verified (Vals AI)70.0%92.0%GLM 5.3 Flash
Terminal-Bench 4 (Vals AI)Not measured37.4%Only GLM 5.3 Flash measured
Vibe Code Bench (Vals AI)22.6%30.8%GLM 5.3 Flash
Code migration (Vals AI)Not measured20.5%Only GLM 5.3 Flash measured
ProgramBench (Vals AI)Not measured0.0%Only GLM 5.3 Flash measured
IOI (Vals AI)Not measured52.5%Only GLM 5.3 Flash measured
Terminal-Bench 2.1 (Vals AI)Not measured62.9%Only GLM 5.3 Flash measured
Vibe Code Bench 1-100 (Vals AI)Not measured16.0%Only GLM 5.3 Flash measured
SkillsBench (Vals AI)Not measured40.2%Only GLM 5.3 Flash measured
CyberBench (Vals AI)Not measured67.9%Only GLM 5.3 Flash measured
SciCodeNot measured51.6%Only GLM 5.3 Flash measured
Terminal-Bench46.5%Not measuredOnly Claude Sonnet 4.5 measured
FrontierCodeNot measured31.8%Only GLM 5.3 Flash measured
FrontierSWENot measured18.1%Only GLM 5.3 Flash measured
GSO-Bench14.7%Not measuredOnly Claude Sonnet 4.5 measured
WeirdML47.7%Not measuredOnly Claude Sonnet 4.5 measured
Cybench60.0%Not measuredOnly Claude Sonnet 4.5 measured
ALE-BenchNot measured303.6Only GLM 5.3 Flash measured
LMArena Text: coding14881507GLM 5.3 Flash
LMArena Text: software and IT14731500GLM 5.3 Flash
LMArena WebDev: React13861624GLM 5.3 Flash
LMArena WebDev: HTML13991577GLM 5.3 Flash
LMArena WebDev: from an imageNot measured1578Only GLM 5.3 Flash measured
Neither model has a result on the other 10 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
AA Intelligence Index20.741.8GLM 5.3 Flash
Epoch Capabilities Index146.7153.1GLM 5.3 Flash
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
Agentic work benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
AA Agentic Index15.850.9GLM 5.3 Flash
Design Arena: agents building web apps1060Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: agents building full-stack apps1050Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: agents building mobile apps1137Not measuredOnly Claude Sonnet 4.5 measured
LiveBench researchNot measured70.1%Only GLM 5.3 Flash measured
LiveBench browserNot measured84.0%Only GLM 5.3 Flash measured
LiveBench long agenticNot measured28.4%Only GLM 5.3 Flash measured
SREBench (Vals AI)Not measured0.8%Only GLM 5.3 Flash measured
Finance Agent (Vals AI)Not measured57.9%Only GLM 5.3 Flash measured
Tax Agent Bench (Vals AI)Not measured31.6%Only GLM 5.3 Flash measured
Legal Research Bench (Vals AI)Not measured45.2%Only GLM 5.3 Flash measured
Harvey's Legal Agent Benchmark (Vals AI)Not measured10.4%Only GLM 5.3 Flash measured
Excel Modeling Benchmark (Vals AI)Not measured55.9%Only GLM 5.3 Flash measured
Terminal-Bench-Science (Vals AI)Not measured2.9%Only GLM 5.3 Flash measured
APEX-AgentsNot measured52.8%Only GLM 5.3 Flash measured
METR time horizons67.4%Not measuredOnly Claude Sonnet 4.5 measured
Remote Labor Index2.1%Not measuredOnly Claude Sonnet 4.5 measured
GDPval42.5%Not measuredOnly Claude Sonnet 4.5 measured
DeepResearch Bench52.6%Not measuredOnly Claude Sonnet 4.5 measured
OSWorld62.9%Not measuredOnly Claude Sonnet 4.5 measured
Vending-Bench 2$3,839Not measuredOnly Claude Sonnet 4.5 measured
Berkeley Function Calling Leaderboard (BFCL)73.2%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 19 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index19
Reasoning benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
GPQA Diamond81.6%86.4%GLM 5.3 Flash
LiveBench reasoningNot measured77.6%Only GLM 5.3 Flash measured
MMMU Pro (Vals AI)79.3%86.0%GLM 5.3 Flash
GPQA Diamond (Artificial Analysis run)Not measured91.2%Only GLM 5.3 Flash measured
Humanity's Last Exam (Artificial Analysis run)Not measured39.9%Only GLM 5.3 Flash measured
GPQA Diamond (Epoch AI run)82.3%90.2%GLM 5.3 Flash
ARC-AGI63.7%91.0%GLM 5.3 Flash
ARC-AGI-213.6%65.8%GLM 5.3 Flash
SimpleBench54.3%Not measuredOnly Claude Sonnet 4.5 measured
Chess puzzles10.0%21.0%GLM 5.3 Flash
Mystery game puzzles17.0%8.0%Claude Sonnet 4.5
EBR-bench2.4%Not measuredOnly Claude Sonnet 4.5 measured
VPCT39.8%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: hard prompts14621490GLM 5.3 Flash
LMArena Text: expert14831511GLM 5.3 Flash
LMArena Text: hard prompts in English14711488GLM 5.3 Flash
LMArena Vision: diagramsNot measured1317Only GLM 5.3 Flash measured
LMArena Vision: homeworkNot measured1318Only GLM 5.3 Flash measured
Kagi LLM Benchmark57.9%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index06
Math benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
AIME88.2%Not measuredOnly Claude Sonnet 4.5 measured
MGSM (Vals AI)94.3%Not measuredOnly Claude Sonnet 4.5 measured
OTIS Mock AIME77.8%93.9%GLM 5.3 Flash
FrontierMath, tiers 1 to 323.9%55.8%GLM 5.3 Flash
FrontierMath, tier 42.4%17.1%GLM 5.3 Flash
ProofBench19.0%21.0%GLM 5.3 Flash
MATH level 597.7%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: math14491503GLM 5.3 Flash
LMArena Text: mathematical work14621497GLM 5.3 Flash
Neither model has a result on the other 4 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index25
Knowledge benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
MMLU Pro87.4%86.1%Claude Sonnet 4.5
LegalBench (Vals AI)84.1%83.9%Claude Sonnet 4.5
CaseLaw (Vals AI)62.2%Not measuredOnly Claude Sonnet 4.5 measured
CorpFin (Vals AI)62.0%Not measuredOnly Claude Sonnet 4.5 measured
TaxEval (Vals AI)73.3%75.6%GLM 5.3 Flash
MortgageTax (Vals AI)64.0%Not measuredOnly Claude Sonnet 4.5 measured
MedQA (Vals AI)94.7%Not measuredOnly Claude Sonnet 4.5 measured
MedCode (Vals AI)44.1%Not measuredOnly Claude Sonnet 4.5 measured
SimpleQA Verified30.7%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: science14481484GLM 5.3 Flash
LMArena Text: medicine and healthcare14441475GLM 5.3 Flash
LMArena Text: legal and government14511473GLM 5.3 Flash
LMArena Text: business and finance14401460GLM 5.3 Flash
FACTS Benchmark Suite40.6%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index08
Web design benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
Design Arena: websites11891272GLM 5.3 Flash
Design Arena: UI components11701316GLM 5.3 Flash
Design Arena: game dev11661278GLM 5.3 Flash
Design Arena: data viz11671262GLM 5.3 Flash
Design Arena: 3D11571316GLM 5.3 Flash
Design Arena: all code categories11821282GLM 5.3 Flash
Design Arena: SVG11151285GLM 5.3 Flash
Design Arena: ASCII art12051267GLM 5.3 Flash
LiveBench designNot measured77.2%Only GLM 5.3 Flash measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index117
General benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
Vals IndexNot measured50.9%Only GLM 5.3 Flash measured
LiveBench data analysisNot measured76.4%Only GLM 5.3 Flash measured
SAGE (Vals AI)36.1%Not measuredOnly Claude Sonnet 4.5 measured
MedScribe (Vals AI)84.5%88.9%GLM 5.3 Flash
Long context reasoning (AA-LCR)Not measured80.0%Only GLM 5.3 Flash measured
DTBench83.2%Not measuredOnly Claude Sonnet 4.5 measured
LMCA38.8%Not measuredOnly Claude Sonnet 4.5 measured
Surface Evolver BenchNot measured52.5%Only GLM 5.3 Flash measured
LMArena Text14381471GLM 5.3 Flash
LMArena Text: instruction following14591478GLM 5.3 Flash
LMArena Text: creative writing14421441Claude Sonnet 4.5
LMArena VisionNot measured1294Only GLM 5.3 Flash measured
LMArena Text: English14501474GLM 5.3 Flash
LMArena Text: non-English14251462GLM 5.3 Flash
LMArena Text: Chinese14601531GLM 5.3 Flash
LMArena Text: German14271462GLM 5.3 Flash
LMArena Text: Japanese13901444GLM 5.3 Flash
LMArena Text: Korean14021436GLM 5.3 Flash
LMArena Text: French14591491GLM 5.3 Flash
LMArena Text: Spanish14581475GLM 5.3 Flash
LMArena Text: Russian14371465GLM 5.3 Flash
LMArena Text: Polish14231450GLM 5.3 Flash
LMArena Text: multi-turn14651469GLM 5.3 Flash
LMArena Text: longer queries14751481GLM 5.3 Flash
LMArena Text: writing and language14421455GLM 5.3 Flash
LMArena Text: entertainment and media14281440GLM 5.3 Flash
LMArena Vision: EnglishNot measured1295Only GLM 5.3 Flash measured
LMArena Vision: ChineseNot measured1363Only GLM 5.3 Flash measured
LMArena Vision: reading textNot measured1299Only GLM 5.3 Flash measured
LMArena Vision: humorNot measured1279Only GLM 5.3 Flash measured
LMArena Vision: creative writingNot measured1270Only GLM 5.3 Flash measured
LMArena Document1450Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 14 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Sonnet 4.5 and GLM 5.3 Flash
BenchmarkClaude Sonnet 4.5GLM 5.3 FlashLeader
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 4.5$0.011Fits in one request
GLM 5.3 Flash$0.0004Fits in one request

GLM 5.3 Flash costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 4.5$0.195Fits in one request
GLM 5.3 Flash$0.0090Fits in one request

GLM 5.3 Flash costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 4.5$0.750Fits in one request
GLM 5.3 Flash$0.035Fits in one request

GLM 5.3 Flash 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 4.5 and GLM 5.3 Flash
SpecificationAnthropic Claude Sonnet 4.5Z.ai GLM 5.3 Flash
MakerAnthropicZ.ai
WeightsNo public weights listedOpen weights
ReleasedSeptember 29, 2025August 26, 2026
Context window1M1.05M
Input $/Mtok$3.00$0.15
Output $/Mtok$15.00$0.50
Coding index39.557.7
Independent measurements behind it36
Cost per solved task$1.16$0.02
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 4.5 better than GLM 5.3 Flash for coding?

Pick GLM 5.3 Flash for coding: it scores 57.7 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5. Pick Claude Sonnet 4.5 for work measured by Mystery game puzzles or MMLU Pro, where it leads.

Which is cheaper, Claude Sonnet 4.5 or GLM 5.3 Flash?

Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens; GLM 5.3 Flash costs $0.15 and $0.50. Per solved SWE-bench Verified task, Claude Sonnet 4.5 costs $1.16 and GLM 5.3 Flash $0.02.

Which has the bigger context window, Claude Sonnet 4.5 or GLM 5.3 Flash?

GLM 5.3 Flash, with 1.05M tokens against 1M.

How many benchmarks is the Claude Sonnet 4.5 vs GLM 5.3 Flash comparison based on?

61 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 4.5's coding index rests on 3 independent benchmarks and GLM 5.3 Flash's on 6. Where only one model has a result, the page says so instead of naming a winner.

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