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Claude Opus 5 vs GLM 5.3 Flash

Claude Opus 5 leads GLM 5.3 Flash on coding, 83.0 to 57.7 on the Vibe Coding Index, and GLM 5.3 Flash costs 50.0x less per output token ($0.50 vs $25.00 per million). Updated October 22, 2026; 99 benchmarks have a result for both.

Replace Claude Opus 5 Replace GLM 5.3 Flash
Claude Opus 5Anthropic
Coding
83.0
Overall
81.6
Output $/M
$25.00
95
GLM 5.3 FlashZ.ai
Coding
57.7
Overall
66.0
Output $/M
$0.50
3
vs boards won of 99 shared, 1 tied

Claude Opus 5 or GLM 5.3 Flash: which to pick

Pick Claude Opus 5 for coding: it scores 83.0 on the Vibe Coding Index against 57.7 for GLM 5.3 Flash.

Pick GLM 5.3 Flash for output tokens 50.0x cheaper ($0.50 vs $25.00 per million) and a lower cost per solved task ($0.02 against $1.33).

Model AClaude Opus 5Anthropic83.0/1006 independent benchmarks$1.33 per solved taskModel BGLM 5.3 FlashZ.ai57.7/1006 independent benchmarks$0.02 per solved task
Shared results
99
Claude Opus 5 only
32
GLM 5.3 Flash only
3
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 Opus 5 83.0 from 6 benchmarks, GLM 5.3 Flash 57.7 from 6 benchmarks.
Widest category
Math, 30.3 points apart on average over 6 shared benchmarks.
Widest single gap
ProofBench: Claude Opus 5 99.0% against GLM 5.3 Flash 21.0%, 78.0 points apart on a 0 to 100 scale.
Output price
Claude Opus 5 $25.00 against GLM 5.3 Flash $0.50 per million output tokens, 50.0x apart.
Context window
Claude Opus 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 Opus 5BarsGLM 5.3 FlashTies
Coding221
Intelligence20
Agentic work1001 tie
Reasoning150
Math60
Knowledge61
Web design90
General251
All shared boards9531 tie
CodingLike-for-likeSix of these boards feed the Vibe Coding Index221
Coding benchmarks for Claude Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 5GLM 5.3 FlashLeader
LiveBench coding90.8%80.6%Claude Opus 5
LMArena WebDev16891607Claude Opus 5
AA Coding Index78.071.5Claude Opus 5
LiveCodeBench (Vals AI)89.0%80.5%Claude Opus 5
SWE-bench Verified (Vals AI)97.0%92.0%Claude Opus 5
Terminal-Bench 4 (Vals AI)53.5%37.4%Claude Opus 5
Vibe Code Bench (Vals AI)88.4%30.8%Claude Opus 5
Code migration (Vals AI)57.5%20.5%Claude Opus 5
ProgramBench (Vals AI)3.0%0.0%Claude Opus 5
IOI (Vals AI)84.3%52.5%Claude Opus 5
Terminal-Bench 2.1 (Vals AI)84.6%62.9%Claude Opus 5
Vibe Code Bench 1-100 (Vals AI)28.5%16.0%Claude Opus 5
SkillsBench (Vals AI)60.4%40.2%Claude Opus 5
CyberBench (Vals AI)65.4%67.9%GLM 5.3 Flash
SciCode56.4%51.6%Claude Opus 5
FrontierCode53.4%31.8%Claude Opus 5
FrontierSWE52.0%18.1%Claude Opus 5
WeirdML91.8%Not measuredOnly Claude Opus 5 measured
ALE-Bench2164.6303.6Claude Opus 5
LMArena Text: coding15331507Claude Opus 5
LMArena Text: software and IT15271500Claude Opus 5
LMArena WebDev: React17111624Claude Opus 5
LMArena WebDev: HTML16801577Claude Opus 5
LMArena WebDev: from an image16621578Claude Opus 5
SciCode13.8%Not measuredOnly Claude Opus 5 measured
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 Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 5GLM 5.3 FlashLeader
AA Intelligence Index50.841.8Claude Opus 5
Epoch Capabilities Index163.9153.1Claude Opus 5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index100
Agentic work benchmarks for Claude Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 5GLM 5.3 FlashLeader
AA Agentic Index56.550.9Claude Opus 5
Design Arena: agents building web apps1266Not measuredOnly Claude Opus 5 measured
Design Arena: agents building full-stack apps1306Not measuredOnly Claude Opus 5 measured
Design Arena: agents building mobile apps1348Not measuredOnly Claude Opus 5 measured
Design Arena: agents building Android apps1257Not measuredOnly Claude Opus 5 measured
Design Arena: agents building Godot games1279Not measuredOnly Claude Opus 5 measured
Design Arena: agents building games1261Not measuredOnly Claude Opus 5 measured
Design Arena: PowerPoint slides1240Not measuredOnly Claude Opus 5 measured
LiveBench research88.9%70.1%Claude Opus 5
LiveBench browser84.0%84.0%Tie
LiveBench long agentic62.1%28.4%Claude Opus 5
SREBench (Vals AI)12.2%0.8%Claude Opus 5
Finance Agent (Vals AI)58.6%57.9%Claude Opus 5
Tax Agent Bench (Vals AI)45.5%31.6%Claude Opus 5
Legal Research Bench (Vals AI)55.3%45.2%Claude Opus 5
Harvey's Legal Agent Benchmark (Vals AI)Not measured10.4%Only GLM 5.3 Flash measured
Excel Modeling Benchmark (Vals AI)73.6%55.9%Claude Opus 5
BioMysteryBench (Vals AI)79.3%Not measuredOnly Claude Opus 5 measured
Terminal-Bench-Science (Vals AI)27.1%2.9%Claude Opus 5
Vals Science Index47.9%Not measuredOnly Claude Opus 5 measured
Time Horizon Index (Vals AI)18.8%Not measuredOnly Claude Opus 5 measured
CUA-bench (Vals AI)9.0%Not measuredOnly Claude Opus 5 measured
APEX-Agents65.8%52.8%Claude Opus 5
OSWorld 2.031.4%Not measuredOnly Claude Opus 5 measured
BALROG63.4%Not measuredOnly Claude Opus 5 measured
PostTrainBench35.0%Not measuredOnly Claude Opus 5 measured
Vending-Bench 2$11,182Not measuredOnly Claude Opus 5 measured
LMArena Search1242Not measuredOnly Claude Opus 5 measured
Neither model has a result on the other 13 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index150
Reasoning benchmarks for Claude Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 5GLM 5.3 FlashLeader
GPQA Diamond93.4%86.4%Claude Opus 5
LiveBench reasoning91.2%77.6%Claude Opus 5
MysteryMechanism (Vals AI)37.4%Not measuredOnly Claude Opus 5 measured
MMMU Pro (Vals AI)89.9%86.0%Claude Opus 5
GPQA Diamond (Artificial Analysis run)93.7%91.2%Claude Opus 5
Humanity's Last Exam (Artificial Analysis run)54.9%39.9%Claude Opus 5
GPQA Diamond (Epoch AI run)93.9%90.2%Claude Opus 5
ARC-AGI97.5%91.0%Claude Opus 5
ARC-AGI-290.4%65.8%Claude Opus 5
SimpleBench80.6%Not measuredOnly Claude Opus 5 measured
Chess puzzles43.0%21.0%Claude Opus 5
Mystery game puzzles59.0%8.0%Claude Opus 5
EBR-bench45.7%Not measuredOnly Claude Opus 5 measured
LMArena Text: hard prompts15271490Claude Opus 5
LMArena Text: expert15541511Claude Opus 5
LMArena Text: hard prompts in English15231488Claude Opus 5
LMArena Vision: diagrams13481317Claude Opus 5
LMArena Vision: homework13381318Claude Opus 5
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 Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 5GLM 5.3 FlashLeader
OTIS Mock AIME98.9%93.9%Claude Opus 5
FrontierMath, tiers 1 to 385.6%55.8%Claude Opus 5
FrontierMath, tier 473.2%17.1%Claude Opus 5
ProofBench99.0%21.0%Claude Opus 5
LMArena Text: math15331503Claude Opus 5
LMArena Text: mathematical work15441497Claude Opus 5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index61
Knowledge benchmarks for Claude Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 5GLM 5.3 FlashLeader
MMLU Pro91.6%86.1%Claude Opus 5
LegalBench (Vals AI)87.0%83.9%Claude Opus 5
CorpFin (Vals AI)73.2%Not measuredOnly Claude Opus 5 measured
TaxEval (Vals AI)75.1%75.6%GLM 5.3 Flash
MortgageTax (Vals AI)72.1%Not measuredOnly Claude Opus 5 measured
MedCode (Vals AI)63.6%Not measuredOnly Claude Opus 5 measured
SimpleQA Verified59.9%Not measuredOnly Claude Opus 5 measured
LMArena Text: science15311484Claude Opus 5
LMArena Text: medicine and healthcare15251475Claude Opus 5
LMArena Text: legal and government15301473Claude Opus 5
LMArena Text: business and finance15011460Claude Opus 5
Neither model has a result on the other 7 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index90
Web design benchmarks for Claude Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 5GLM 5.3 FlashLeader
Design Arena: websites13091272Claude Opus 5
Design Arena: UI components13461316Claude Opus 5
Design Arena: game dev13371278Claude Opus 5
Design Arena: data viz13291262Claude Opus 5
Design Arena: 3D13341316Claude Opus 5
Design Arena: all code categories13231282Claude Opus 5
Design Arena: SVG13111285Claude Opus 5
Design Arena: ASCII art13521267Claude Opus 5
LiveBench design83.0%77.2%Claude Opus 5
GeneralLike-for-likePublic boards, shown as published, kept out of the index251
General benchmarks for Claude Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 5GLM 5.3 FlashLeader
Vals IndexNot measured50.9%Only GLM 5.3 Flash measured
LiveBench data analysis74.6%76.4%GLM 5.3 Flash
Public Benefits Bench (Vals AI)76.9%Not measuredOnly Claude Opus 5 measured
SAGE (Vals AI)49.4%Not measuredOnly Claude Opus 5 measured
MedScribe (Vals AI)91.0%88.9%Claude Opus 5
Vals Multimodal Index73.9%Not measuredOnly Claude Opus 5 measured
Long context reasoning (AA-LCR)82.0%80.0%Claude Opus 5
DTBench97.9%Not measuredOnly Claude Opus 5 measured
LMCA64.5%Not measuredOnly Claude Opus 5 measured
Surface Evolver BenchNot measured52.5%Only GLM 5.3 Flash measured
Furniture assembly60.8%Not measuredOnly Claude Opus 5 measured
LMArena Text15091471Claude Opus 5
LMArena Text: instruction following15181478Claude Opus 5
LMArena Text: creative writing14931441Claude Opus 5
LMArena Vision13201294Claude Opus 5
LMArena Text: English15081474Claude Opus 5
LMArena Text: non-English15021462Claude Opus 5
LMArena Text: Chinese15731531Claude Opus 5
LMArena Text: German15271462Claude Opus 5
LMArena Text: Japanese15201444Claude Opus 5
LMArena Text: Korean15171436Claude Opus 5
LMArena Text: French15191491Claude Opus 5
LMArena Text: Spanish15231475Claude Opus 5
LMArena Text: Russian15071465Claude Opus 5
LMArena Text: Polish15221450Claude Opus 5
LMArena Text: multi-turn15001469Claude Opus 5
LMArena Text: longer queries15171481Claude Opus 5
LMArena Text: writing and language14991455Claude Opus 5
LMArena Text: entertainment and media14811440Claude Opus 5
LMArena Vision: English13151295Claude Opus 5
LMArena Vision: Chinese14001363Claude Opus 5
LMArena Vision: reading text13291299Claude Opus 5
LMArena Vision: humor12931279Claude Opus 5
LMArena Vision: creative writing13131270Claude Opus 5
LMArena Document1516Not measuredOnly Claude Opus 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 Opus 5 and GLM 5.3 Flash
BenchmarkClaude Opus 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 Opus 5$0.018Fits 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 Opus 5$0.325Fits 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 Opus 5$1.25Fits 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 Opus 5 and GLM 5.3 Flash
SpecificationAnthropic Claude Opus 5Z.ai GLM 5.3 Flash
MakerAnthropicZ.ai
WeightsNo public weights listedOpen weights
ReleasedJuly 24, 2026August 26, 2026
Context window1M1.05M
Input $/Mtok$5.00$0.15
Output $/Mtok$25.00$0.50
Coding index83.057.7
Independent measurements behind it66
Cost per solved task$1.33$0.02
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 5 better than GLM 5.3 Flash for coding?

Pick Claude Opus 5 for coding: it scores 83.0 on the Vibe Coding Index against 57.7 for GLM 5.3 Flash. Pick GLM 5.3 Flash for output tokens 50.0x cheaper ($0.50 vs $25.00 per million) and a lower cost per solved task ($0.02 against $1.33).

Which is cheaper, Claude Opus 5 or GLM 5.3 Flash?

Claude Opus 5 costs $5.00 per million input tokens and $25.00 per million output tokens; GLM 5.3 Flash costs $0.15 and $0.50. Per solved SWE-bench Verified task, Claude Opus 5 costs $1.33 and GLM 5.3 Flash $0.02.

Which has the bigger context window, Claude Opus 5 or GLM 5.3 Flash?

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

How many benchmarks is the Claude Opus 5 vs GLM 5.3 Flash comparison based on?

99 benchmarks have a result for both models as of October 22, 2026. Claude Opus 5's coding index rests on 6 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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