Enter opens the highlighted result. Esc closes.

GLM 5.3 Flash vs Grok 4.20

GLM 5.3 Flash leads Grok 4.20 on coding, 57.7 to 33.3 on the Vibe Coding Index, and GLM 5.3 Flash costs 5.0x less per output token ($0.50 vs $2.50 per million). Updated October 21, 2026; 30 benchmarks have a result for both.

Replace GLM 5.3 Flash Replace Grok 4.20
GLM 5.3 FlashZ.ai
Coding
57.7
Overall
41.8
Output $/M
$0.50
27
Grok 4.20xAI
Coding
33.3
Overall
25.7
Output $/M
$2.50
3
vs boards won of 30 shared

GLM 5.3 Flash or Grok 4.20: which to pick

Pick GLM 5.3 Flash for coding: it scores 57.7 on the Vibe Coding Index against 33.3 for Grok 4.20.

Pick Grok 4.20 for a larger context window (2M against 1.05M tokens) and work measured by LiveCodeBench (Vals AI) or GPQA Diamond, where it leads.

Model AGLM 5.3 FlashZ.ai57.7/1006 independent benchmarks$0.02 per solved taskModel BGrok 4.20xAI33.3/1002 independent benchmarks$0.72 per solved task
Shared results
30
GLM 5.3 Flash only
72
Grok 4.20 only
24
Like-for-like categories
7 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, Grok 4.20 33.3 from 2 benchmarks.
Widest category
Agentic work, 32.4 points apart on average over 4 shared benchmarks.
Widest single gap
Excel Modeling Benchmark (Vals AI): GLM 5.3 Flash 55.9% against Grok 4.20 11.7%, 44.2 points apart on a 0 to 100 scale.
Output price
GLM 5.3 Flash $0.50 against Grok 4.20 $2.50 per million output tokens, 5.0x apart.
Context window
GLM 5.3 Flash takes 1.05M tokens, Grok 4.20 2M.

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 FlashBarsGrok 4.20Ties
Coding41
Intelligence20
Agentic work40
Reasoning51
Knowledge21
Web design80
General20
All shared boards273
CodingLike-for-likeSix of these boards feed the Vibe Coding Index41
Coding benchmarks for GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
LiveBench coding80.6%Not measuredOnly GLM 5.3 Flash measured
LMArena WebDev1607Not measuredOnly GLM 5.3 Flash measured
AA Coding Index71.5Not measuredOnly GLM 5.3 Flash measured
LiveCodeBench (Vals AI)80.5%84.3%Grok 4.20
SWE-bench Verified (Vals AI)92.0%72.2%GLM 5.3 Flash
Terminal-Bench 4 (Vals AI)37.4%Not measuredOnly GLM 5.3 Flash measured
Vibe Code Bench (Vals AI)30.8%4.1%GLM 5.3 Flash
Code migration (Vals AI)20.5%0.3%GLM 5.3 Flash
ProgramBench (Vals AI)0.0%Not measuredOnly GLM 5.3 Flash measured
IOI (Vals AI)52.5%Not measuredOnly GLM 5.3 Flash measured
Terminal-Bench 2.1 (Vals AI)62.9%44.2%GLM 5.3 Flash
Vibe Code Bench 1-100 (Vals AI)16.0%Not measuredOnly GLM 5.3 Flash measured
SkillsBench (Vals AI)40.2%Not measuredOnly GLM 5.3 Flash measured
CyberBench (Vals AI)67.9%Not measuredOnly GLM 5.3 Flash measured
SciCode51.6%Not measuredOnly GLM 5.3 Flash measured
Terminal-Bench Hard (Artificial Analysis run)Not measured37.9%Only Grok 4.20 measured
Terminal-BenchNot measured57.3%Only Grok 4.20 measured
FrontierCode31.8%Not measuredOnly GLM 5.3 Flash measured
FrontierSWE18.1%Not measuredOnly GLM 5.3 Flash measured
WeirdMLNot measured52.3%Only Grok 4.20 measured
ALE-Bench303.6Not measuredOnly GLM 5.3 Flash measured
LMArena Text: coding1507Not measuredOnly GLM 5.3 Flash measured
LMArena Text: software and IT1500Not measuredOnly GLM 5.3 Flash measured
LMArena WebDev: React1624Not measuredOnly GLM 5.3 Flash measured
LMArena WebDev: HTML1577Not measuredOnly GLM 5.3 Flash measured
LMArena WebDev: from an image1578Not measuredOnly GLM 5.3 Flash measured
Neither model has a result on the other 12 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
AA Intelligence Index41.825.7GLM 5.3 Flash
Epoch Capabilities Index153.1152.1GLM 5.3 Flash
Agentic workLike-for-likePublic boards, shown as published, kept out of the index40
Agentic work benchmarks for GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
AA Agentic Index50.9Not measuredOnly GLM 5.3 Flash measured
Design Arena: agents building web appsNot measured1144Only Grok 4.20 measured
Design Arena: agents building full-stack appsNot measured1054Only Grok 4.20 measured
Design Arena: agents building mobile appsNot measured1090Only Grok 4.20 measured
Design Arena: agents building Android appsNot measured1052Only Grok 4.20 measured
Design Arena: agents building Godot gamesNot measured1089Only Grok 4.20 measured
Design Arena: HTML slidesNot measured1180Only Grok 4.20 measured
LiveBench research70.1%Not measuredOnly GLM 5.3 Flash measured
LiveBench browser84.0%Not measuredOnly GLM 5.3 Flash measured
LiveBench long agentic28.4%Not measuredOnly GLM 5.3 Flash measured
SREBench (Vals AI)0.8%Not measuredOnly GLM 5.3 Flash measured
Finance Agent (Vals AI)57.9%28.5%GLM 5.3 Flash
Tax Agent Bench (Vals AI)31.6%7.0%GLM 5.3 Flash
Legal Research Bench (Vals AI)45.2%13.9%GLM 5.3 Flash
Harvey's Legal Agent Benchmark (Vals AI)10.4%Not measuredOnly GLM 5.3 Flash measured
Excel Modeling Benchmark (Vals AI)55.9%11.7%GLM 5.3 Flash
Terminal-Bench-Science (Vals AI)2.9%Not measuredOnly GLM 5.3 Flash measured
τ²-Bench TelecomNot measured93.0%Only Grok 4.20 measured
APEX-Agents52.8%Not measuredOnly GLM 5.3 Flash measured
Vending-Bench 2Not measured$4,663Only Grok 4.20 measured
Neither model has a result on the other 19 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index51
Reasoning benchmarks for GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
GPQA Diamond86.4%88.6%Grok 4.20
LiveBench reasoning77.6%Not measuredOnly GLM 5.3 Flash measured
MMMU Pro (Vals AI)86.0%83.5%GLM 5.3 Flash
GPQA Diamond (Artificial Analysis run)91.2%91.1%GLM 5.3 Flash
Humanity's Last Exam (Artificial Analysis run)39.9%34.5%GLM 5.3 Flash
GPQA Diamond (Epoch AI run)90.2%Not measuredOnly GLM 5.3 Flash measured
ARC-AGI91.0%89.5%GLM 5.3 Flash
ARC-AGI-265.8%65.1%GLM 5.3 Flash
Chess puzzles21.0%Not measuredOnly GLM 5.3 Flash measured
Mystery game puzzles8.0%Not measuredOnly GLM 5.3 Flash measured
LMArena Text: hard prompts1490Not measuredOnly GLM 5.3 Flash measured
LMArena Text: expert1511Not measuredOnly GLM 5.3 Flash measured
LMArena Text: hard prompts in English1488Not measuredOnly GLM 5.3 Flash measured
LMArena Vision: diagrams1317Not measuredOnly GLM 5.3 Flash measured
LMArena Vision: homework1318Not measuredOnly GLM 5.3 Flash measured
Neither model has a result on the other 6 boards here
MathDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
Math benchmarks for GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
AIMENot measured96.5%Only Grok 4.20 measured
OTIS Mock AIME93.9%Not measuredOnly GLM 5.3 Flash measured
FrontierMath, tiers 1 to 355.8%Not measuredOnly GLM 5.3 Flash measured
FrontierMath, tier 417.1%Not measuredOnly GLM 5.3 Flash measured
ProofBench21.0%Not measuredOnly GLM 5.3 Flash measured
LMArena Text: math1503Not measuredOnly GLM 5.3 Flash measured
LMArena Text: mathematical work1497Not measuredOnly GLM 5.3 Flash measured
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index21
Knowledge benchmarks for GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
MMLU Pro86.1%86.3%Grok 4.20
LegalBench (Vals AI)83.9%77.7%GLM 5.3 Flash
CaseLaw (Vals AI)Not measured54.4%Only Grok 4.20 measured
CorpFin (Vals AI)Not measured63.7%Only Grok 4.20 measured
TaxEval (Vals AI)75.6%74.1%GLM 5.3 Flash
MortgageTax (Vals AI)Not measured45.4%Only Grok 4.20 measured
MedQA (Vals AI)Not measured94.5%Only Grok 4.20 measured
MedCode (Vals AI)Not measured32.2%Only Grok 4.20 measured
LMArena Text: science1484Not measuredOnly GLM 5.3 Flash measured
LMArena Text: medicine and healthcare1475Not measuredOnly GLM 5.3 Flash measured
LMArena Text: legal and government1473Not measuredOnly GLM 5.3 Flash measured
LMArena Text: business and finance1460Not measuredOnly GLM 5.3 Flash measured
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index80
Web design benchmarks for GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
Design Arena: websites12721229GLM 5.3 Flash
Design Arena: UI components13161199GLM 5.3 Flash
Design Arena: game dev12781192GLM 5.3 Flash
Design Arena: data viz12611217GLM 5.3 Flash
Design Arena: 3D13161193GLM 5.3 Flash
Design Arena: all code categories12821221GLM 5.3 Flash
Design Arena: SVG12841164GLM 5.3 Flash
Design Arena: ASCII art12681174GLM 5.3 Flash
LiveBench design77.2%Not measuredOnly GLM 5.3 Flash measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index20
General benchmarks for GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
Vals Index50.9%Not measuredOnly GLM 5.3 Flash measured
LiveBench data analysis76.4%Not measuredOnly GLM 5.3 Flash measured
SAGE (Vals AI)Not measured38.2%Only Grok 4.20 measured
MedScribe (Vals AI)88.9%63.4%GLM 5.3 Flash
Vals Multimodal IndexNot measured39.1%Only Grok 4.20 measured
IFBenchNot measured81.2%Only Grok 4.20 measured
Long context reasoning (AA-LCR)80.0%69.0%GLM 5.3 Flash
DTBenchNot measured90.1%Only Grok 4.20 measured
LMCANot measured38.7%Only Grok 4.20 measured
CL-benchNot measured22.2%Only Grok 4.20 measured
Surface Evolver Bench52.5%Not measuredOnly GLM 5.3 Flash measured
CL-bench LifeNot measured11.9%Only Grok 4.20 measured
LMArena Text1471Not measuredOnly GLM 5.3 Flash measured
LMArena Text: instruction following1478Not measuredOnly GLM 5.3 Flash measured
LMArena Text: creative writing1441Not measuredOnly GLM 5.3 Flash measured
LMArena Vision1294Not measuredOnly GLM 5.3 Flash measured
LMArena Text: English1474Not measuredOnly GLM 5.3 Flash measured
LMArena Text: non-English1462Not measuredOnly GLM 5.3 Flash measured
LMArena Text: Chinese1531Not measuredOnly GLM 5.3 Flash measured
LMArena Text: German1462Not measuredOnly GLM 5.3 Flash measured
LMArena Text: Japanese1444Not measuredOnly GLM 5.3 Flash measured
LMArena Text: Korean1436Not measuredOnly GLM 5.3 Flash measured
LMArena Text: French1491Not measuredOnly GLM 5.3 Flash measured
LMArena Text: Spanish1475Not measuredOnly GLM 5.3 Flash measured
LMArena Text: Russian1465Not measuredOnly GLM 5.3 Flash measured
LMArena Text: Polish1450Not measuredOnly GLM 5.3 Flash measured
LMArena Text: multi-turn1469Not measuredOnly GLM 5.3 Flash measured
LMArena Text: longer queries1481Not measuredOnly GLM 5.3 Flash measured
LMArena Text: writing and language1455Not measuredOnly GLM 5.3 Flash measured
LMArena Text: entertainment and media1440Not measuredOnly GLM 5.3 Flash measured
LMArena Vision: English1295Not measuredOnly GLM 5.3 Flash measured
LMArena Vision: Chinese1363Not measuredOnly GLM 5.3 Flash measured
LMArena Vision: reading text1299Not measuredOnly GLM 5.3 Flash measured
LMArena Vision: humor1279Not measuredOnly GLM 5.3 Flash measured
LMArena Vision: creative writing1270Not measuredOnly GLM 5.3 Flash 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 GLM 5.3 Flash and Grok 4.20
BenchmarkGLM 5.3 FlashGrok 4.20Leader
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
Grok 4.20$0.0025Fits 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
Grok 4.20$0.070Fits 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
Grok 4.20$0.275Fits 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 Grok 4.20
SpecificationZ.ai GLM 5.3 FlashSpaceXAI Grok 4.20
MakerZ.aixAI
WeightsOpen weightsNo public weights listed
ReleasedAugust 26, 2026March 31, 2026
Context window1.05M2M
Input $/Mtok$0.15$1.25
Output $/Mtok$0.50$2.50
Coding index57.733.3
Independent measurements behind it62
Cost per solved task$0.02$0.72
SourceOpenRouter listingOpenRouter listing

Questions

Is GLM 5.3 Flash better than Grok 4.20 for coding?

Pick GLM 5.3 Flash for coding: it scores 57.7 on the Vibe Coding Index against 33.3 for Grok 4.20. Pick Grok 4.20 for a larger context window (2M against 1.05M tokens) and work measured by LiveCodeBench (Vals AI) or GPQA Diamond, where it leads.

Which is cheaper, GLM 5.3 Flash or Grok 4.20?

GLM 5.3 Flash costs $0.15 per million input tokens and $0.50 per million output tokens; Grok 4.20 costs $1.25 and $2.50. Per solved SWE-bench Verified task, GLM 5.3 Flash costs $0.02 and Grok 4.20 $0.72.

Which has the bigger context window, GLM 5.3 Flash or Grok 4.20?

Grok 4.20, with 2M tokens against 1.05M.

How many benchmarks is the GLM 5.3 Flash vs Grok 4.20 comparison based on?

30 benchmarks have a result for both models as of October 21, 2026. GLM 5.3 Flash's coding index rests on 6 independent benchmarks and Grok 4.20's on 2. Where only one model has a result, the page says so instead of naming a winner.

Compare next

Embed this comparison on your site

Free under CC BY 4.0, while the source link stays visible. Preview the frame · Terms and other embeds

<iframe src="https://llmbenchmark.ai/embed/compare/glm-5-3-flash-vs-grok-4-20" title="GLM 5.3 Flash vs Grok 4.20, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/glm-5-3-flash-vs-grok-4-20">LLMBenchmark.ai, GLM 5.3 Flash vs Grok 4.20</a></p>