GLM 5 vs Grok 4.20

Updated October 21, 2026. 38 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace GLM 5 Replace Grok 4.20

GLM 5Z.ai

Coding: 41.7
Overall: 27.9
Output $/M: $3.20

Grok 4.20xAI

Coding: 33.3
Overall: 25.7
Output $/M: $2.50

vs boards won of 38 shared

Decision reading

Pick GLM 5 for coding: it scores 41.7 on the Vibe Coding Index against 33.3 for Grok 4.20.

Pick Grok 4.20 when output tokens cost 1.3x less, or when the context window is larger, 2M against 205K tokens.

Model AGLM 5Z.ai41.7/1003 independent benchmarks$0.63 per solved task Model BGrok 4.20xAI33.3/1002 independent benchmarks$0.72 per solved task

383716

Shared results: 38
GLM 5 only: 37
Grok 4.20 only: 16
Like-for-like categories: 8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

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.

Coding
Vibe Coding Index, six public coding benchmarks
GLM 5
GLM 5 scores 41.7 against 33.3.
3 and 2 benchmarks behind the scores
Intelligence
AA Intelligence Index
GLM 5
GLM 5 leads, 27.9 against 25.7.
Same board, both measured
Reasoning
GPQA Diamond
Grok 4.20
Grok 4.20 leads, 88.6% against 83.3%.
Same board, both measured
Math
AIME
Grok 4.20
Grok 4.20 leads, 96.5% against 91.7%.
Same board, both measured
Knowledge
MMLU Pro
Grok 4.20
Grok 4.20 leads, 86.3% against 86.0%.
Same board, both measured
Web design
Design Arena: websites
GLM 5
GLM 5 leads, 1247 against 1229.
Same board, both measured
Long documents
Listed context window
Grok 4.20
Grok 4.20 takes 2M tokens against 205K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Grok 4.20
GLM 5 $0.0026, Grok 4.20 $0.0025 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
GLM 5
GLM 5 $0.63, Grok 4.20 $0.72.
Published attempt cost and pass rate

At a glance

Coding index: GLM 5 41.7 from 3 benchmarks, Grok 4.20 33.3 from 2 benchmarks.
Widest category: Reasoning, 24.9 points apart on average over 5 shared benchmarks.
Widest single gap: ARC-AGI-2: GLM 5 4.9% against Grok 4.20 65.1%, 60.3 points apart on a 0 to 100 scale.
Output price: GLM 5 $3.20 against Grok 4.20 $2.50 per million output tokens, 1.3x apart.
Context window: GLM 5 takes 205K 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
Category	GLM 5	Grok 4.20
Coding	2	4
Intelligence	1	1
Agentic work	5	2
Reasoning	0	5
Math	0	1
Knowledge	1	5
Web design	7	1
General	1	2
All shared boards	17	21

CodingLike-for-likeSix of these boards feed the Vibe Coding Index24

Coding benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
SWE-bench Verified	72.8%	Not measured	Only GLM 5 measured
SWE-bench Multilingual	69.7%	Not measured	Only GLM 5 measured
LMArena WebDev	1435	Not measured	Only GLM 5 measured
LiveCodeBench (Vals AI)	81.9%	84.3%	Grok 4.20
SWE-bench Verified (Vals AI)	71.4%	72.2%	Grok 4.20
Vibe Code Bench (Vals AI)	23.4%	4.1%	GLM 5
Code migration (Vals AI)	Not measured	0.3%	Only Grok 4.20 measured
Terminal-Bench 2.1 (Vals AI)	Not measured	44.2%	Only Grok 4.20 measured
Terminal-Bench Hard (Artificial Analysis run)	43.2%	37.9%	GLM 5
Terminal-Bench	52.4%	57.3%	Grok 4.20
WeirdML	48.2%	52.3%	Grok 4.20
ALE-Bench	765.6	Not measured	Only GLM 5 measured
LMArena Text: coding	1461	Not measured	Only GLM 5 measured
LMArena Text: software and IT	1460	Not measured	Only GLM 5 measured
LMArena WebDev: React	1424	Not measured	Only GLM 5 measured
LMArena WebDev: HTML	1450	Not measured	Only GLM 5 measured
Neither model has a result on the other 22 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11

Intelligence benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
AA Intelligence Index	27.9	25.7	GLM 5
Epoch Capabilities Index	145.8	152.1	Grok 4.20

Agentic workLike-for-likePublic boards, shown as published, kept out of the index52

Agentic work benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
Design Arena: agents building web apps	Not measured	1144	Only Grok 4.20 measured
Design Arena: agents building full-stack apps	1123	1054	GLM 5
Design Arena: agents building mobile apps	1136	1090	GLM 5
Design Arena: agents building Android apps	1153	1052	GLM 5
Design Arena: agents building Godot games	1144	1089	GLM 5
Design Arena: HTML slides	1148	1180	Grok 4.20
Finance Agent (Vals AI)	Not measured	28.5%	Only Grok 4.20 measured
Tax Agent Bench (Vals AI)	Not measured	7.0%	Only Grok 4.20 measured
Legal Research Bench (Vals AI)	Not measured	13.9%	Only Grok 4.20 measured
Excel Modeling Benchmark (Vals AI)	Not measured	11.7%	Only Grok 4.20 measured
τ²-Bench Telecom	98.2%	93.0%	GLM 5
Vending-Bench 2	$4,432	$4,663	Grok 4.20
Neither model has a result on the other 27 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index05

Reasoning benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
GPQA Diamond	83.3%	88.6%	Grok 4.20
MMMU Pro (Vals AI)	Not measured	83.5%	Only Grok 4.20 measured
GPQA Diamond (Artificial Analysis run)	82.0%	91.1%	Grok 4.20
Humanity's Last Exam (Artificial Analysis run)	29.3%	34.5%	Grok 4.20
GPQA Diamond (Epoch AI run)	87.8%	Not measured	Only GLM 5 measured
ARC-AGI	44.7%	89.5%	Grok 4.20
ARC-AGI-2	4.9%	65.1%	Grok 4.20
SimpleBench	53.2%	Not measured	Only GLM 5 measured
LMArena Text: hard prompts	1452	Not measured	Only GLM 5 measured
LMArena Text: expert	1454	Not measured	Only GLM 5 measured
LMArena Text: hard prompts in English	1460	Not measured	Only GLM 5 measured
Neither model has a result on the other 10 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index01

Math benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
AIME	91.7%	96.5%	Grok 4.20
OTIS Mock AIME	80.0%	Not measured	Only GLM 5 measured
LMArena Text: math	1440	Not measured	Only GLM 5 measured
LMArena Text: mathematical work	1451	Not measured	Only GLM 5 measured
Neither model has a result on the other 9 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index15

Knowledge benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
MMLU Pro	86.0%	86.3%	Grok 4.20
LegalBench (Vals AI)	84.1%	77.7%	GLM 5
CaseLaw (Vals AI)	52.5%	54.4%	Grok 4.20
CorpFin (Vals AI)	62.9%	63.7%	Grok 4.20
TaxEval (Vals AI)	70.0%	74.1%	Grok 4.20
MortgageTax (Vals AI)	Not measured	45.4%	Only Grok 4.20 measured
MedQA (Vals AI)	94.3%	94.5%	Grok 4.20
MedCode (Vals AI)	Not measured	32.2%	Only Grok 4.20 measured
LMArena Text: science	1460	Not measured	Only GLM 5 measured
LMArena Text: medicine and healthcare	1455	Not measured	Only GLM 5 measured
LMArena Text: legal and government	1453	Not measured	Only GLM 5 measured
LMArena Text: business and finance	1430	Not measured	Only GLM 5 measured
Neither model has a result on the other 5 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index71

Web design benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
Design Arena: websites	1247	1229	GLM 5
Design Arena: UI components	1230	1199	GLM 5
Design Arena: game dev	1234	1192	GLM 5
Design Arena: data viz	1228	1217	GLM 5
Design Arena: 3D	1229	1193	GLM 5
Design Arena: all code categories	1246	1221	GLM 5
Design Arena: SVG	1168	1164	GLM 5
Design Arena: ASCII art	1146	1174	Grok 4.20
Neither model has a result on the other 1 board here

GeneralLike-for-likePublic boards, shown as published, kept out of the index12

General benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
SAGE (Vals AI)	Not measured	38.2%	Only Grok 4.20 measured
MedScribe (Vals AI)	Not measured	63.4%	Only Grok 4.20 measured
Vals Multimodal Index	Not measured	39.1%	Only Grok 4.20 measured
IFBench	72.3%	81.2%	Grok 4.20
Long context reasoning (AA-LCR)	75.7%	69.0%	GLM 5
DTBench	Not measured	90.1%	Only Grok 4.20 measured
LMCA	Not measured	38.7%	Only Grok 4.20 measured
CL-bench	18.7%	22.2%	Grok 4.20
CL-bench Life	Not measured	11.9%	Only Grok 4.20 measured
LMArena Text	1446	Not measured	Only GLM 5 measured
LMArena Text: instruction following	1428	Not measured	Only GLM 5 measured
LMArena Text: creative writing	1438	Not measured	Only GLM 5 measured
LMArena Text: English	1458	Not measured	Only GLM 5 measured
LMArena Text: non-English	1430	Not measured	Only GLM 5 measured
LMArena Text: Chinese	1511	Not measured	Only GLM 5 measured
LMArena Text: German	1447	Not measured	Only GLM 5 measured
LMArena Text: Japanese	1416	Not measured	Only GLM 5 measured
LMArena Text: Korean	1423	Not measured	Only GLM 5 measured
LMArena Text: French	1456	Not measured	Only GLM 5 measured
LMArena Text: Spanish	1454	Not measured	Only GLM 5 measured
LMArena Text: Russian	1436	Not measured	Only GLM 5 measured
LMArena Text: Polish	1434	Not measured	Only GLM 5 measured
LMArena Text: multi-turn	1456	Not measured	Only GLM 5 measured
LMArena Text: longer queries	1446	Not measured	Only GLM 5 measured
LMArena Text: writing and language	1437	Not measured	Only GLM 5 measured
LMArena Text: entertainment and media	1426	Not measured	Only GLM 5 measured
Neither model has a result on the other 20 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for GLM 5 and Grok 4.20
Benchmark	GLM 5	Grok 4.20	Leader
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$0.0026Fits in one request

Grok 4.20$0.0025Fits in one request

Grok 4.20 costs less

Repository review

50K input + 3K output tokens

GLM 5$0.060Fits in one request

Grok 4.20$0.070Fits in one request

GLM 5 costs less

Agent loop

200K input + 10K output tokens

GLM 5$0.232Exceeds the context window

Grok 4.20$0.275Fits in one request

GLM 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 GLM 5 and Grok 4.20
Specification	Z.ai GLM 5	SpaceXAI Grok 4.20
Maker	Z.ai	xAI
Weights	Open weights	No public weights listed
Released	February 11, 2026	March 31, 2026
Context window	205K	2M
Input $/Mtok	$1.00	$1.25
Output $/Mtok	$3.20	$2.50
Coding index	41.7	33.3
Independent measurements behind it	3	2
Cost per solved task	$0.63	$0.72
Source	OpenRouter listing	OpenRouter listing

Questions

Is GLM 5 better than Grok 4.20 for coding?

Pick GLM 5 for coding: it scores 41.7 on the Vibe Coding Index against 33.3 for Grok 4.20. Pick Grok 4.20 when output tokens cost 1.3x less, or when the context window is larger, 2M against 205K tokens.

Which is cheaper, GLM 5 or Grok 4.20?

GLM 5 costs $1.00 per million input tokens and $3.20 per million output tokens; Grok 4.20 costs $1.25 and $2.50. Per solved SWE-bench Verified task, GLM 5 costs $0.63 and Grok 4.20 $0.72.

Which has the bigger context window, GLM 5 or Grok 4.20?

Grok 4.20, with 2M tokens against 205K.

How many benchmarks is the GLM 5 vs Grok 4.20 comparison based on?

38 benchmarks have a result for both models as of October 21, 2026. GLM 5's coding index rests on 3 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.

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Decision reading

Which one for your work

Coding

Intelligence

Reasoning

Math

Knowledge

Web design

Long documents

Everyday cost

Cost per solved task