Model comparison

GPT-5 vs Grok 4.20 (Non-Reasoning)

GPT-5 is the stronger model overall, scoring 50.9 to 48.6 on the Noometry Index. Grok 4.20 (Non-Reasoning) costs 2.2× less per token, which makes it the better buy when GPT-5's lead doesn't matter for your workload.

Last verified October 10, 2026. 38 shared benchmarks.

GPT-5 OpenAI

50.9

Rank #45 Confirmed

Grok 4.20 (Non-Reasoning) xAI

48.6

Rank #54 Confirmed

Summary

They share 38 benchmarks with published results for both. GPT-5 scores higher in 5 categories and Grok 4.20 (Non-Reasoning) in 5 categories; 10 gaps are clear of the uncertainty.
The widest gap is in long context, where GPT-5 leads 69.5 to 45.5.
The biggest single-benchmark swing is ARC-AGI-2: 9.9% for GPT-5 and 65.1% for Grok 4.20 (Non-Reasoning).
Grok 4.20 (Non-Reasoning) is cheaper at $1.25 / $2.50 per million input/output tokens, against $1.25 / $10 for GPT-5.
Grok 4.20 (Non-Reasoning) accepts more context: 1M tokens versus 400K.

Side by side

GPT-5 and Grok 4.20 (Non-Reasoning) specifications
	GPT-5	Grok 4.20 (Non-Reasoning)
Provider	OpenAI	xAI
Noometry Index	50.9	48.6
Released	2025-08-07	2026-02-17
Weights	Proprietary	Proprietary
Context window	400K	1M
Max output	128K	30K
Input $ / M tokens	$1.25	$1.25
Output $ / M tokens	$10	$2.50
Results tracked	69	46

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Category by category

Coding GPT-5 leads

GPT-5: 50.3 (#47), Grok 4.20 (Non-Reasoning): 42.1 (#112)

Coding benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
LMArena WebDev	1418	1375
WeirdML	60.7%	52.3%
LMArena Coding	1436	1459
ALE-Bench	1,162	1,150
SWE-bench Verified	73.6%	—
SWE-bench Verified (bash only)	65%	—
Aider Polyglot	88%	—
SciCode	42.9%	—
GSO	6.9%	—
AlgoTune	1.67	—

Agentic & Tool Use Grok 4.20 (Non-Reasoning) leads

GPT-5: 33.1 (#56), Grok 4.20 (Non-Reasoning): 34.4 (#46)

Agentic & Tool Use benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
Terminal-Bench	49.6%	57.3%
LMArena Search	1133	1189
GDPval	34.8%	—
Remote Labor Index	1.7%	—
τ²-bench Banking	—	18%
DeepResearch Bench	49.6%	—
BALROG	32.8%	—
METR Time Horizons	69.6%	—
Vending-Bench 2	—	4,663

Reasoning Grok 4.20 (Non-Reasoning) leads

GPT-5: 38.3 (#64), Grok 4.20 (Non-Reasoning): 52.3 (#32)

Reasoning benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
ARC-AGI-2	9.9%	65.1%
Kagi LLM Benchmark	72.7%	75%
ARC-AGI-1	65.7%	89.5%
Chess Puzzles	37%	24%
LMArena Hard Prompts	1416	1451
DTBench	90.7%	90.1%
LMCA	40%	38.7%
Epoch Capabilities Index	150	151.98
ForecastBench	61.4	61.4
SimpleBench	56.7%	—
NYT Connections (extended)	—	85.4%
CritPt	12.6%	—
EnigmaEval	10.5%	—
Thematic Generalization	—	63.8%
EBR-Bench	12.7%	—
Mystery Game Puzzles	23%	—

Math GPT-5 leads

GPT-5: 55.0 (#44), Grok 4.20 (Non-Reasoning): 48.2 (#65)

Math benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
FrontierMath (Tiers 1-3)	55.4%	44.9%
FrontierMath Tier 4	22%	17.1%
OTIS Mock AIME 2024-2025	91.4%	92.2%
ProofBench	18%	14%
LMArena Math	1407	1455
Omni-MATH	64.7%	—
MATH Level 5	98.1%	—
FrontierMath (Feb 2025 set)	32.4%	—
FrontierMath Tier 4 (v1)	12.5%	—

Knowledge GPT-5 leads

GPT-5: 56.6 (#43), Grok 4.20 (Non-Reasoning): 52.8 (#60)

Knowledge benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
GPQA Diamond	86.2%	89.3%
SimpleQA Verified	50.1%	30.2%
LMArena Expert	1419	1439
Humanity's Last Exam	25.3%	—
MMLU-Pro	86.3%	—
Confabulations	10.3%	—
Vectara Hallucination Rate	14.7%	—
GPQA (HELM)	79.2%	—

Multimodal GPT-5 leads

GPT-5: 46.8 (#13), Grok 4.20 (Non-Reasoning): 33.3 (#98)

Multimodal benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
LMArena Vision	1232	1263
GeoBench	81%	—
VPCT	66%	—
Blueprint-Bench 2	—	0%
LMArena Document	—	1416

Multilingual Grok 4.20 (Non-Reasoning) leads

GPT-5: 51.4 (#110), Grok 4.20 (Non-Reasoning): 54.5 (#40)

Multilingual benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
LMArena Non-English	1397	1441
LMArena Chinese	1422	1481
LMArena French	1410	1476
LMArena German	1416	1465
LMArena Japanese	1409	1449
LMArena Korean	1360	1417
LMArena Russian	1406	1458
LMArena Spanish	1399	1443

Instruction Following Grok 4.20 (Non-Reasoning) leads

GPT-5: 73.8 (#113), Grok 4.20 (Non-Reasoning): 74.8 (#83)

Instruction Following benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
LMArena Instruction Following	1388	1420
IFEval	87.5%	—

Long Context GPT-5 leads

GPT-5: 69.5 (#2), Grok 4.20 (Non-Reasoning): 45.5 (#34)

Long Context benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
LMArena Longer Query	1399	1437
Fiction.LiveBench	97.2%	—
CL-bench	—	22.2%
CL-bench Life	—	11.9%

Writing & Preference Grok 4.20 (Non-Reasoning) leads

GPT-5: 63.4 (#65), Grok 4.20 (Non-Reasoning): 65.7 (#44)

Writing & Preference benchmarks
Benchmark	GPT-5	Grok 4.20 (Non-Reasoning)
LMArena Text	1406	1451
LMArena Creative Writing	1365	1438
EQ-Bench Creative Writing	1627	1574
LMArena Multi-Turn	1426	1456
Short-Story Creative Writing	86%	—
WildBench	85.7%	—

Frequently asked questions

Is GPT-5 better than Grok 4.20 (Non-Reasoning)?

Which is cheaper, GPT-5 or Grok 4.20 (Non-Reasoning)?

Grok 4.20 (Non-Reasoning) is cheaper. It lists at $1.25 per million input tokens and $2.50 per million output tokens; GPT-5 lists at $1.25 and $10.

Is GPT-5 or Grok 4.20 (Non-Reasoning) better for coding?

GPT-5 scores higher on coding benchmarks: 50.3 versus 42.1 in the Noometry coding category.

Which has the bigger context window?

Grok 4.20 (Non-Reasoning) does, with 1M tokens against 400K.

How many benchmarks do GPT-5 and Grok 4.20 (Non-Reasoning) share?

38 benchmarks have published results for both models. GPT-5 has 69 scored results on Noometry and Grok 4.20 (Non-Reasoning) has 46.