GPT-5.4 Mini vs Grok 4.20

GPT-5.4 Mini leads Grok 4.20 on coding, 35.8 to 33.3 on the Vibe Coding Index, and Grok 4.20 costs 1.8x less per output token ($2.50 vs $4.50 per million). Updated October 21, 2026; 33 benchmarks have a result for both.

Replace GPT-5.4 Mini Replace Grok 4.20

GPT-5.4 MiniOpenAI

Coding: 35.8
Overall: 44.0
Output $/M: $4.50

Grok 4.20xAI

Coding: 33.3
Overall: 41.0
Output $/M: $2.50

vs boards won of 33 shared

GPT-5.4 Mini or Grok 4.20: which to pick

Pick GPT-5.4 Mini for coding: it scores 35.8 on the Vibe Coding Index against 33.3 for Grok 4.20.

Pick Grok 4.20 for output tokens 1.8x cheaper ($2.50 vs $4.50 per million) and a larger context window (2M against 400K tokens).

Model AGPT-5.4 MiniOpenAI35.8/1005 independent benchmarks$0.70 per solved task Model BGrok 4.20xAI33.3/1002 independent benchmarks$0.72 per solved task

335622

Shared results: 33
GPT-5.4 Mini only: 56
Grok 4.20 only: 22
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.

Coding
Vibe Coding Index, six public coding benchmarks
GPT-5.4 Mini
GPT-5.4 Mini scores 35.8 against 33.3.
5 and 2 benchmarks behind the scores
Intelligence
AA Intelligence Index
Grok 4.20
Grok 4.20 leads, 25.7 against 24.1.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only GPT-5.4 Mini has a AA Agentic Index result, 17.9.
Directional only
Reasoning
GPQA Diamond
Grok 4.20
Grok 4.20 leads, 88.6% against 83.1%.
Same board, both measured
Math
AIME
Grok 4.20
Grok 4.20 leads, 96.5% against 95.6%.
Same board, both measured
Knowledge
MMLU Pro
Grok 4.20
Grok 4.20 leads, 86.3% against 84.5%.
Same board, both measured
Web design
Design Arena: websites
No call
Only Grok 4.20 has a Design Arena: websites result, 1229.
Directional only
Long documents
Listed context window
Grok 4.20
Grok 4.20 takes 2M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Grok 4.20
GPT-5.4 Mini $0.0030, Grok 4.20 $0.0025 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
GPT-5.4 Mini
GPT-5.4 Mini $0.70, Grok 4.20 $0.72.
Published attempt cost and pass rate

At a glance

Coding index: GPT-5.4 Mini 35.8 from 5 benchmarks, Grok 4.20 33.3 from 2 benchmarks.
Widest category: Reasoning, 18.4 points apart on average over 7 shared benchmarks.
Widest single gap: ARC-AGI-2: GPT-5.4 Mini 18.9% against Grok 4.20 65.1%, 46.2 points apart on a 0 to 100 scale.
Output price: GPT-5.4 Mini $4.50 against Grok 4.20 $2.50 per million output tokens, 1.8x apart.
Context window: GPT-5.4 Mini takes 400K 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	GPT-5.4 Mini	Grok 4.20
Coding	6	1
Intelligence	0	2
Agentic work	3	2
Reasoning	0	7
Math	0	1
Knowledge	1	4
General	4	2
All shared boards	14	19

CodingLike-for-likeSix of these boards feed the Vibe Coding Index61

Coding benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	Grok 4.20	Leader
LMArena WebDev	1397	Not measured	Only GPT-5.4 Mini measured
AA Coding Index	56.1	Not measured	Only GPT-5.4 Mini measured
LiveCodeBench (Vals AI)	81.5%	84.3%	Grok 4.20
SWE-bench Verified (Vals AI)	73.0%	72.2%	GPT-5.4 Mini
Terminal-Bench 4 (Vals AI)	2.5%	Not measured	Only GPT-5.4 Mini measured
Vibe Code Bench (Vals AI)	48.0%	4.1%	GPT-5.4 Mini
Code migration (Vals AI)	12.9%	0.3%	GPT-5.4 Mini
ProgramBench (Vals AI)	0.0%	Not measured	Only GPT-5.4 Mini measured
Terminal-Bench 2.1 (Vals AI)	54.7%	44.2%	GPT-5.4 Mini
SciCode	52.1%	Not measured	Only GPT-5.4 Mini measured
Terminal-Bench Hard (Artificial Analysis run)	52.3%	37.9%	GPT-5.4 Mini
Terminal-Bench	Not measured	57.3%	Only Grok 4.20 measured
FrontierCode	27.0%	Not measured	Only GPT-5.4 Mini measured
WeirdML	60.3%	52.3%	GPT-5.4 Mini
ALE-Bench	1188.6	Not measured	Only GPT-5.4 Mini measured
LMArena Text: coding	1438	Not measured	Only GPT-5.4 Mini measured
LMArena Text: software and IT	1436	Not measured	Only GPT-5.4 Mini measured
LMArena WebDev: React	1386	Not measured	Only GPT-5.4 Mini measured
LMArena WebDev: HTML	1419	Not measured	Only GPT-5.4 Mini measured
Neither model has a result on the other 20 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02

Intelligence benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	Grok 4.20	Leader
AA Intelligence Index	24.1	25.7	Grok 4.20
Epoch Capabilities Index	148.7	152.1	Grok 4.20

Agentic workLike-for-likePublic boards, shown as published, kept out of the index32

Agentic work benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	Grok 4.20	Leader
AA Agentic Index	17.9	Not measured	Only GPT-5.4 Mini measured
Design Arena: agents building web apps	Not measured	1144	Only Grok 4.20 measured
Design Arena: agents building full-stack apps	Not measured	1054	Only Grok 4.20 measured
Design Arena: agents building mobile apps	Not measured	1090	Only Grok 4.20 measured
Design Arena: agents building Android apps	Not measured	1052	Only Grok 4.20 measured
Design Arena: agents building Godot games	Not measured	1089	Only Grok 4.20 measured
Design Arena: HTML slides	Not measured	1180	Only Grok 4.20 measured
Finance Agent (Vals AI)	45.4%	28.5%	GPT-5.4 Mini
Tax Agent Bench (Vals AI)	8.8%	7.0%	GPT-5.4 Mini
Legal Research Bench (Vals AI)	12.5%	13.9%	Grok 4.20
Excel Modeling Benchmark (Vals AI)	45.4%	11.7%	GPT-5.4 Mini
τ²-Bench Telecom	83.3%	93.0%	Grok 4.20
DeepResearch Bench	36.3%	Not measured	Only GPT-5.4 Mini measured
Vending-Bench 2	Not measured	$4,663	Only Grok 4.20 measured
Neither model has a result on the other 27 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index07

Reasoning benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	Grok 4.20	Leader
GPQA Diamond	83.1%	88.6%	Grok 4.20
MMMU Pro (Vals AI)	79.3%	83.5%	Grok 4.20
GPQA Diamond (Artificial Analysis run)	87.5%	91.1%	Grok 4.20
Humanity's Last Exam (Artificial Analysis run)	28.1%	34.5%	Grok 4.20
GPQA Diamond (Epoch AI run)	86.9%	Not measured	Only GPT-5.4 Mini measured
ARC-AGI	63.7%	89.5%	Grok 4.20
ARC-AGI-2	18.9%	65.1%	Grok 4.20
Chess puzzles	23.0%	Not measured	Only GPT-5.4 Mini measured
Mystery game puzzles	11.0%	Not measured	Only GPT-5.4 Mini measured
LMArena Text: hard prompts	1424	Not measured	Only GPT-5.4 Mini measured
LMArena Text: expert	1435	Not measured	Only GPT-5.4 Mini measured
LMArena Text: hard prompts in English	1420	Not measured	Only GPT-5.4 Mini measured
LMArena Vision: diagrams	1266	Not measured	Only GPT-5.4 Mini measured
LMArena Vision: homework	1285	Not measured	Only GPT-5.4 Mini measured
Kagi LLM Benchmark	37.9%	75.0%	Grok 4.20
Neither model has a result on the other 7 boards here

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

Math benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	Grok 4.20	Leader
AIME	95.6%	96.5%	Grok 4.20
OTIS Mock AIME	88.9%	Not measured	Only GPT-5.4 Mini measured
FrontierMath, tiers 1 to 3	51.2%	Not measured	Only GPT-5.4 Mini measured
FrontierMath, tier 4	9.8%	Not measured	Only GPT-5.4 Mini measured
ProofBench	21.0%	Not measured	Only GPT-5.4 Mini measured
LMArena Text: math	1418	Not measured	Only GPT-5.4 Mini measured
LMArena Text: mathematical work	1429	Not measured	Only GPT-5.4 Mini measured
Neither model has a result on the other 6 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index14

Knowledge benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	Grok 4.20	Leader
MMLU Pro	84.5%	86.3%	Grok 4.20
LegalBench (Vals AI)	Not measured	77.7%	Only Grok 4.20 measured
CaseLaw (Vals AI)	51.7%	54.4%	Grok 4.20
CorpFin (Vals AI)	60.9%	63.7%	Grok 4.20
TaxEval (Vals AI)	71.2%	74.1%	Grok 4.20
MortgageTax (Vals AI)	63.5%	45.4%	GPT-5.4 Mini
MedQA (Vals AI)	Not measured	94.5%	Only Grok 4.20 measured
MedCode (Vals AI)	Not measured	32.2%	Only Grok 4.20 measured
SimpleQA Verified	29.4%	Not measured	Only GPT-5.4 Mini measured
LMArena Text: science	1417	Not measured	Only GPT-5.4 Mini measured
LMArena Text: medicine and healthcare	1395	Not measured	Only GPT-5.4 Mini measured
LMArena Text: legal and government	1414	Not measured	Only GPT-5.4 Mini measured
LMArena Text: business and finance	1418	Not measured	Only GPT-5.4 Mini measured
Neither model has a result on the other 5 boards here

Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared

Web design benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	Grok 4.20	Leader
Design Arena: websites	Not measured	1229	Only Grok 4.20 measured
Design Arena: UI components	Not measured	1199	Only Grok 4.20 measured
Design Arena: game dev	Not measured	1192	Only Grok 4.20 measured
Design Arena: data viz	Not measured	1217	Only Grok 4.20 measured
Design Arena: 3D	Not measured	1193	Only Grok 4.20 measured
Design Arena: all code categories	Not measured	1221	Only Grok 4.20 measured
Design Arena: SVG	Not measured	1164	Only Grok 4.20 measured
Design Arena: ASCII art	Not measured	1174	Only Grok 4.20 measured
Neither model has a result on the other 1 board here

GeneralLike-for-likePublic boards, shown as published, kept out of the index42

General benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	Grok 4.20	Leader
SAGE (Vals AI)	50.8%	38.2%	GPT-5.4 Mini
MedScribe (Vals AI)	Not measured	63.4%	Only Grok 4.20 measured
Vals Multimodal Index	54.2%	39.1%	GPT-5.4 Mini
IFBench	73.3%	81.2%	Grok 4.20
Long context reasoning (AA-LCR)	77.0%	69.0%	GPT-5.4 Mini
DTBench	80.0%	90.1%	Grok 4.20
LMCA	40.8%	38.7%	GPT-5.4 Mini
CL-bench	Not measured	22.2%	Only Grok 4.20 measured
CL-bench Life	Not measured	11.9%	Only Grok 4.20 measured
LMArena Text	1412	Not measured	Only GPT-5.4 Mini measured
LMArena Text: instruction following	1405	Not measured	Only GPT-5.4 Mini measured
LMArena Text: creative writing	1370	Not measured	Only GPT-5.4 Mini measured
LMArena Vision	1245	Not measured	Only GPT-5.4 Mini measured
LMArena Text: English	1412	Not measured	Only GPT-5.4 Mini measured
LMArena Text: non-English	1405	Not measured	Only GPT-5.4 Mini measured
LMArena Text: Chinese	1446	Not measured	Only GPT-5.4 Mini measured
LMArena Text: German	1408	Not measured	Only GPT-5.4 Mini measured
LMArena Text: Japanese	1375	Not measured	Only GPT-5.4 Mini measured
LMArena Text: Korean	1370	Not measured	Only GPT-5.4 Mini measured
LMArena Text: French	1441	Not measured	Only GPT-5.4 Mini measured
LMArena Text: Spanish	1405	Not measured	Only GPT-5.4 Mini measured
LMArena Text: Russian	1417	Not measured	Only GPT-5.4 Mini measured
LMArena Text: Polish	1415	Not measured	Only GPT-5.4 Mini measured
LMArena Text: multi-turn	1429	Not measured	Only GPT-5.4 Mini measured
LMArena Text: longer queries	1408	Not measured	Only GPT-5.4 Mini measured
LMArena Text: writing and language	1393	Not measured	Only GPT-5.4 Mini measured
LMArena Text: entertainment and media	1373	Not measured	Only GPT-5.4 Mini measured
LMArena Vision: English	1244	Not measured	Only GPT-5.4 Mini measured
LMArena Vision: Chinese	1286	Not measured	Only GPT-5.4 Mini measured
LMArena Vision: reading text	1253	Not measured	Only GPT-5.4 Mini measured
LMArena Vision: humor	1235	Not measured	Only GPT-5.4 Mini measured
LMArena Vision: recognizing things	1218	Not measured	Only GPT-5.4 Mini measured
LMArena Vision: creative writing	1222	Not measured	Only GPT-5.4 Mini measured
Neither model has a result on the other 13 boards here

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

Image generation benchmarks for GPT-5.4 Mini and Grok 4.20
Benchmark	GPT-5.4 Mini	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

GPT-5.4 Mini$0.0030Fits in one request

Grok 4.20$0.0025Fits in one request

Grok 4.20 costs less

Repository review

50K input + 3K output tokens

GPT-5.4 Mini$0.051Fits in one request

Grok 4.20$0.070Fits in one request

GPT-5.4 Mini costs less

Agent loop

200K input + 10K output tokens

GPT-5.4 Mini$0.195Fits in one request

Grok 4.20$0.275Fits in one request

GPT-5.4 Mini 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 GPT-5.4 Mini and Grok 4.20
Specification	OpenAI GPT-5.4 Mini	SpaceXAI Grok 4.20
Maker	OpenAI	xAI
Weights	No public weights listed	No public weights listed
Released	March 17, 2026	March 31, 2026
Context window	400K	2M
Input $/Mtok	$0.75	$1.25
Output $/Mtok	$4.50	$2.50
Coding index	35.8	33.3
Independent measurements behind it	5	2
Cost per solved task	$0.70	$0.72
Source	OpenRouter listing	OpenRouter listing

Questions

Is GPT-5.4 Mini better than Grok 4.20 for coding?

Pick GPT-5.4 Mini for coding: it scores 35.8 on the Vibe Coding Index against 33.3 for Grok 4.20. Pick Grok 4.20 for output tokens 1.8x cheaper ($2.50 vs $4.50 per million) and a larger context window (2M against 400K tokens).

Which is cheaper, GPT-5.4 Mini or Grok 4.20?

GPT-5.4 Mini costs $0.75 per million input tokens and $4.50 per million output tokens; Grok 4.20 costs $1.25 and $2.50. Per solved SWE-bench Verified task, GPT-5.4 Mini costs $0.70 and Grok 4.20 $0.72.

Which has the bigger context window, GPT-5.4 Mini or Grok 4.20?

Grok 4.20, with 2M tokens against 400K.

How many benchmarks is the GPT-5.4 Mini vs Grok 4.20 comparison based on?

33 benchmarks have a result for both models as of October 21, 2026. GPT-5.4 Mini's coding index rests on 5 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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GPT-5.4 Mini or Grok 4.20: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Math

Knowledge

Web design

Long documents

Everyday cost

Cost per solved task