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GLM 5.3 Flash vs GPT-6 Astra

GPT-6 Astra leads GLM 5.3 Flash on coding, 85.1 to 57.7 on the Vibe Coding Index, and GLM 5.3 Flash costs 100.0x less per output token ($0.50 vs $50.00 per million). Updated October 22, 2026; 92 benchmarks have a result for both.

Replace GLM 5.3 Flash Replace GPT-6 Astra
GLM 5.3 FlashZ.ai
Coding
57.7
Overall
66.0
Output $/M
$0.50
39
GPT-6 AstraOpenAI
Coding
85.1
Overall
83.0
Output $/M
$50.00
52
vs boards won of 92 shared, 1 tied

GLM 5.3 Flash or GPT-6 Astra: which to pick

Pick GPT-6 Astra for coding: it scores 85.1 on the Vibe Coding Index against 57.7 for GLM 5.3 Flash, though on 5 benchmarks against 6.

Pick GLM 5.3 Flash for output tokens 100.0x cheaper ($0.50 vs $50.00 per million) and work measured by CyberBench (Vals AI) or LMArena Text: coding, where it leads.

Model AGLM 5.3 FlashZ.ai57.7/1006 independent benchmarks$0.02 per solved taskModel BGPT-6 AstraOpenAI85.1/1005 independent benchmarksNo cost per solved task
Shared results
92
GLM 5.3 Flash only
10
GPT-6 Astra only
29
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
GLM 5.3 Flash 57.7 from 6 benchmarks, GPT-6 Astra 85.1 from 5 benchmarks.
Widest category
Math, 35.1 points apart on average over 6 shared benchmarks.
Widest single gap
ALE-Bench: GLM 5.3 Flash 303.6 against GPT-6 Astra 2951.3, 88.3 points apart on a 0 to 100 scale.
Output price
GLM 5.3 Flash $0.50 against GPT-6 Astra $50.00 per million output tokens, 100.0x apart.
Context window
GLM 5.3 Flash takes 1.05M tokens, GPT-6 Astra 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
CategoryGLM 5.3 FlashBarsGPT-6 AstraTies
Coding317
Intelligence02
Agentic work471 tie
Reasoning49
Math24
Knowledge40
Web design09
General224
All shared boards39521 tie
CodingLike-for-likeSix of these boards feed the Vibe Coding Index317
Coding benchmarks for GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
LiveBench coding80.6%93.7%GPT-6 Astra
LMArena WebDev16071774GPT-6 Astra
AA Coding Index71.576.9GPT-6 Astra
LiveCodeBench (Vals AI)80.5%Not measuredOnly GLM 5.3 Flash measured
SWE-bench Verified (Vals AI)92.0%Not measuredOnly GLM 5.3 Flash measured
Terminal-Bench 4 (Vals AI)37.4%59.6%GPT-6 Astra
Vibe Code Bench (Vals AI)30.8%89.6%GPT-6 Astra
Code migration (Vals AI)20.5%67.7%GPT-6 Astra
ProgramBench (Vals AI)0.0%5.5%GPT-6 Astra
IOI (Vals AI)52.5%100.0%GPT-6 Astra
Terminal-Bench 2.1 (Vals AI)62.9%87.3%GPT-6 Astra
SWE-bench Multimodal (Vals AI)Not measured43.3%Only GPT-6 Astra measured
Vibe Code Bench 1-100 (Vals AI)16.0%27.6%GPT-6 Astra
SkillsBench (Vals AI)40.2%Not measuredOnly GLM 5.3 Flash measured
CyberBench (Vals AI)67.9%41.1%GLM 5.3 Flash
SciCode51.6%56.5%GPT-6 Astra
FrontierCode31.8%53.3%GPT-6 Astra
FrontierSWE18.1%65.5%GPT-6 Astra
GSO-BenchNot measured79.4%Only GPT-6 Astra measured
WeirdMLNot measured93.3%Only GPT-6 Astra measured
MirrorCodeNot measured46.7%Only GPT-6 Astra measured
ALE-Bench303.62951.3GPT-6 Astra
LMArena Text: coding15071489GLM 5.3 Flash
LMArena Text: software and IT15001474GLM 5.3 Flash
LMArena WebDev: React16241798GPT-6 Astra
LMArena WebDev: HTML15771775GPT-6 Astra
LMArena WebDev: from an image15781726GPT-6 Astra
SciCodeNot measured12.3%Only GPT-6 Astra measured
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
AA Intelligence Index41.852.7GPT-6 Astra
Epoch Capabilities Index153.1168.8GPT-6 Astra
Agentic workLike-for-likePublic boards, shown as published, kept out of the index47
Agentic work benchmarks for GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
AA Agentic Index50.951.0GPT-6 Astra
Design Arena: agents building web appsNot measured1373Only GPT-6 Astra measured
Design Arena: agents building full-stack appsNot measured1357Only GPT-6 Astra measured
Design Arena: agents building mobile appsNot measured1312Only GPT-6 Astra measured
Design Arena: agents building Godot gamesNot measured1348Only GPT-6 Astra measured
Design Arena: PowerPoint slidesNot measured1219Only GPT-6 Astra measured
Design Arena: spreadsheetsNot measured1365Only GPT-6 Astra measured
LiveBench research70.1%85.2%GPT-6 Astra
LiveBench browser84.0%84.0%Tie
LiveBench long agentic28.4%82.4%GPT-6 Astra
SREBench (Vals AI)0.8%56.9%GPT-6 Astra
Finance Agent (Vals AI)57.9%53.5%GLM 5.3 Flash
Tax Agent Bench (Vals AI)31.6%20.7%GLM 5.3 Flash
Legal Research Bench (Vals AI)45.2%39.4%GLM 5.3 Flash
Harvey's Legal Agent Benchmark (Vals AI)10.4%7.1%GLM 5.3 Flash
Excel Modeling Benchmark (Vals AI)55.9%71.7%GPT-6 Astra
BioMysteryBench (Vals AI)Not measured79.3%Only GPT-6 Astra measured
Terminal-Bench-Science (Vals AI)2.9%62.9%GPT-6 Astra
Vals Science IndexNot measured65.1%Only GPT-6 Astra measured
Time Horizon Index (Vals AI)Not measured90.5%Only GPT-6 Astra measured
CUA-bench (Vals AI)Not measured19.2%Only GPT-6 Astra measured
Robo-bench (Vals AI)Not measured23.3%Only GPT-6 Astra measured
APEX-Agents52.8%64.7%GPT-6 Astra
Remote Labor IndexNot measured20.8%Only GPT-6 Astra measured
BALROGNot measured68.3%Only GPT-6 Astra measured
SpireClimbNot measured25.7%Only GPT-6 Astra measured
Vending-Bench 2Not measured$15,515Only GPT-6 Astra measured
Neither model has a result on the other 14 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index49
Reasoning benchmarks for GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
GPQA Diamond86.4%Not measuredOnly GLM 5.3 Flash measured
LiveBench reasoning77.6%92.7%GPT-6 Astra
MysteryMechanism (Vals AI)Not measured53.1%Only GPT-6 Astra measured
MMMU Pro (Vals AI)86.0%Not measuredOnly GLM 5.3 Flash measured
GPQA Diamond (Artificial Analysis run)91.2%96.3%GPT-6 Astra
Humanity's Last Exam (Artificial Analysis run)39.9%54.7%GPT-6 Astra
GPQA Diamond (Epoch AI run)90.2%95.8%GPT-6 Astra
ARC-AGI91.0%98.5%GPT-6 Astra
ARC-AGI-265.8%95.0%GPT-6 Astra
Chess puzzles21.0%74.0%GPT-6 Astra
Mystery game puzzles8.0%84.0%GPT-6 Astra
EBR-benchNot measured76.2%Only GPT-6 Astra measured
LMArena Text: hard prompts14901463GLM 5.3 Flash
LMArena Text: expert15111489GLM 5.3 Flash
LMArena Text: hard prompts in English14881464GLM 5.3 Flash
LMArena Vision: diagrams13171297GLM 5.3 Flash
LMArena Vision: homework13181337GPT-6 Astra
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index24
Math benchmarks for GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
OTIS Mock AIME93.9%100.0%GPT-6 Astra
FrontierMath, tiers 1 to 355.8%93.7%GPT-6 Astra
FrontierMath, tier 417.1%97.6%GPT-6 Astra
ProofBench21.0%99.0%GPT-6 Astra
LMArena Text: math15031465GLM 5.3 Flash
LMArena Text: mathematical work14971484GLM 5.3 Flash
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
Knowledge benchmarks for GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
MMLU Pro86.1%Not measuredOnly GLM 5.3 Flash measured
LegalBench (Vals AI)83.9%Not measuredOnly GLM 5.3 Flash measured
TaxEval (Vals AI)75.6%Not measuredOnly GLM 5.3 Flash measured
MedCode (Vals AI)Not measured48.5%Only GPT-6 Astra measured
SimpleQA VerifiedNot measured75.6%Only GPT-6 Astra measured
LMArena Text: science14841451GLM 5.3 Flash
LMArena Text: medicine and healthcare14751425GLM 5.3 Flash
LMArena Text: legal and government14731462GLM 5.3 Flash
LMArena Text: business and finance14601439GLM 5.3 Flash
FACTS Benchmark SuiteNot measured75.7%Only GPT-6 Astra measured
Neither model has a result on the other 8 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index09
Web design benchmarks for GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
Design Arena: websites12721336GPT-6 Astra
Design Arena: UI components13161393GPT-6 Astra
Design Arena: game dev12781478GPT-6 Astra
Design Arena: data viz12621335GPT-6 Astra
Design Arena: 3D13161500GPT-6 Astra
Design Arena: all code categories12821379GPT-6 Astra
Design Arena: SVG12851431GPT-6 Astra
Design Arena: ASCII art12671353GPT-6 Astra
LiveBench design77.2%82.0%GPT-6 Astra
GeneralLike-for-likePublic boards, shown as published, kept out of the index224
General benchmarks for GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
Vals Index50.9%65.0%GPT-6 Astra
LiveBench data analysis76.4%83.0%GPT-6 Astra
SAGE (Vals AI)Not measured46.4%Only GPT-6 Astra measured
MedScribe (Vals AI)88.9%87.9%GLM 5.3 Flash
Long context reasoning (AA-LCR)80.0%80.7%GPT-6 Astra
DTBenchNot measured97.3%Only GPT-6 Astra measured
LMCANot measured64.4%Only GPT-6 Astra measured
Surface Evolver Bench52.5%Not measuredOnly GLM 5.3 Flash measured
Furniture assemblyNot measured80.0%Only GPT-6 Astra measured
LMArena Text14711441GLM 5.3 Flash
LMArena Text: instruction following14781455GLM 5.3 Flash
LMArena Text: creative writing14411420GLM 5.3 Flash
LMArena Vision12941280GLM 5.3 Flash
LMArena Text: English14741447GLM 5.3 Flash
LMArena Text: non-English14621432GLM 5.3 Flash
LMArena Text: Chinese15311489GLM 5.3 Flash
LMArena Text: German14621459GLM 5.3 Flash
LMArena Text: Japanese14441405GLM 5.3 Flash
LMArena Text: Korean14361428GLM 5.3 Flash
LMArena Text: French14911432GLM 5.3 Flash
LMArena Text: Spanish14751422GLM 5.3 Flash
LMArena Text: Russian14651438GLM 5.3 Flash
LMArena Text: Polish14501422GLM 5.3 Flash
LMArena Text: multi-turn14691447GLM 5.3 Flash
LMArena Text: longer queries14811460GLM 5.3 Flash
LMArena Text: writing and language14551437GLM 5.3 Flash
LMArena Text: entertainment and media14401427GLM 5.3 Flash
LMArena Vision: English12951280GLM 5.3 Flash
LMArena Vision: Chinese13631361GLM 5.3 Flash
LMArena Vision: reading text12991292GLM 5.3 Flash
LMArena Vision: humor1279Not measuredOnly GLM 5.3 Flash measured
LMArena Vision: creative writing12701286GPT-6 Astra
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 GLM 5.3 Flash and GPT-6 Astra
BenchmarkGLM 5.3 FlashGPT-6 AstraLeader
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

GLM 5.3 Flash$0.0004Fits in one request
GPT-6 Astra$0.035Fits in one request

GLM 5.3 Flash costs less

Repository review

50K input + 3K output tokens

GLM 5.3 Flash$0.0090Fits in one request
GPT-6 Astra$0.650Fits in one request

GLM 5.3 Flash costs less

Agent loop

200K input + 10K output tokens

GLM 5.3 Flash$0.035Fits in one request
GPT-6 Astra$2.50Fits 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 GLM 5.3 Flash and GPT-6 Astra
SpecificationZ.ai GLM 5.3 FlashOpenAI GPT-6 Astra
MakerZ.aiOpenAI
WeightsOpen weightsNo public weights listed
ReleasedAugust 26, 2026September 4, 2026
Context window1.05M1.05M
Input $/Mtok$0.15$10.00
Output $/Mtok$0.50$50.00
Coding index57.785.1
Independent measurements behind it65
Cost per solved task$0.02Not computable
SourceOpenRouter listingOpenRouter listing

Questions

Is GLM 5.3 Flash better than GPT-6 Astra for coding?

Pick GPT-6 Astra for coding: it scores 85.1 on the Vibe Coding Index against 57.7 for GLM 5.3 Flash, though on 5 benchmarks against 6. Pick GLM 5.3 Flash for output tokens 100.0x cheaper ($0.50 vs $50.00 per million) and work measured by CyberBench (Vals AI) or LMArena Text: coding, where it leads.

Which is cheaper, GLM 5.3 Flash or GPT-6 Astra?

GLM 5.3 Flash costs $0.15 per million input tokens and $0.50 per million output tokens; GPT-6 Astra costs $10.00 and $50.00. Cost per solved task is known for GLM 5.3 Flash only.

Which has the bigger context window, GLM 5.3 Flash or GPT-6 Astra?

GPT-6 Astra, with 1.05M tokens against 1.05M.

How many benchmarks is the GLM 5.3 Flash vs GPT-6 Astra comparison based on?

92 benchmarks have a result for both models as of October 22, 2026. GLM 5.3 Flash's coding index rests on 6 independent benchmarks and GPT-6 Astra's on 5. Where only one model has a result, the page says so instead of naming a winner.

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