Model comparison

GPT-5.3 Chat vs Grok 4.20 (Non-Reasoning)

Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.6 to 42.8 on the Noometry Index.

Last verified October 10, 2026. 18 shared benchmarks.

GPT-5.3 Chat OpenAI

42.8

Rank #109 Confirmed

Grok 4.20 (Non-Reasoning) xAI

48.6

Rank #54 Confirmed

Summary

They share 18 benchmarks with published results for both. GPT-5.3 Chat scores higher in 0 categories and Grok 4.20 (Non-Reasoning) in 8 categories; 7 gaps are clear of the uncertainty.
The widest gap is in reasoning, where Grok 4.20 (Non-Reasoning) leads 52.3 to 28.5.
Grok 4.20 (Non-Reasoning) is cheaper at $1.25 / $2.50 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
Grok 4.20 (Non-Reasoning) accepts more context: 1M tokens versus 128K.

Side by side

GPT-5.3 Chat and Grok 4.20 (Non-Reasoning) specifications
	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
Provider	OpenAI	xAI
Noometry Index	42.8	48.6
Released	2026-03-03	2026-02-17
Weights	Proprietary	Proprietary
Context window	128K	1M
Max output	16K	30K
Input $ / M tokens	$1.75	$1.25
Output $ / M tokens	$14	$2.50
Results tracked	18	46

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Category by category

Coding Too close to call

GPT-5.3 Chat: 41.4 (#124), Grok 4.20 (Non-Reasoning): 42.1 (#112)

Coding benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Coding	1408	1459
LMArena WebDev	—	1375
WeirdML	—	52.3%
ALE-Bench	—	1,150

Agentic & Tool Use Not comparable

GPT-5.3 Chat: —, Grok 4.20 (Non-Reasoning): 34.4 (#46)

Agentic & Tool Use benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
Terminal-Bench	—	57.3%
τ²-bench Banking	—	18%
LMArena Search	—	1189
Vending-Bench 2	—	4,663

Reasoning Grok 4.20 (Non-Reasoning) leads

GPT-5.3 Chat: 28.5 (#102), Grok 4.20 (Non-Reasoning): 52.3 (#32)

Reasoning benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Hard Prompts	1399	1451
ARC-AGI-2	—	65.1%
Kagi LLM Benchmark	—	75%
NYT Connections (extended)	—	85.4%
ARC-AGI-1	—	89.5%
Chess Puzzles	—	24%
Thematic Generalization	—	63.8%
DTBench	—	90.1%
LMCA	—	38.7%
Epoch Capabilities Index	—	151.98
ForecastBench	—	61.4

Math Grok 4.20 (Non-Reasoning) leads

GPT-5.3 Chat: 38.2 (#142), Grok 4.20 (Non-Reasoning): 48.2 (#65)

Math benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Math	1389	1455
FrontierMath (Tiers 1-3)	—	44.9%
FrontierMath Tier 4	—	17.1%
OTIS Mock AIME 2024-2025	—	92.2%
ProofBench	—	14%

Knowledge Grok 4.20 (Non-Reasoning) leads

GPT-5.3 Chat: 38.8 (#140), Grok 4.20 (Non-Reasoning): 52.8 (#60)

Knowledge benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Expert	1397	1439
GPQA Diamond	—	89.3%
SimpleQA Verified	—	30.2%

Multimodal Not comparable

GPT-5.3 Chat: —, Grok 4.20 (Non-Reasoning): 33.3 (#98)

Multimodal benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Vision	—	1263
Blueprint-Bench 2	—	0%
LMArena Document	—	1416

Multilingual Grok 4.20 (Non-Reasoning) leads

GPT-5.3 Chat: 50.3 (#124), Grok 4.20 (Non-Reasoning): 54.5 (#40)

Multilingual benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Non-English	1382	1441
LMArena Chinese	1432	1481
LMArena French	1397	1476
LMArena German	1384	1465
LMArena Japanese	1352	1449
LMArena Korean	1346	1417
LMArena Russian	1400	1458
LMArena Spanish	1371	1443

Instruction Following Grok 4.20 (Non-Reasoning) leads

GPT-5.3 Chat: 72.8 (#129), Grok 4.20 (Non-Reasoning): 74.8 (#83)

Instruction Following benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Instruction Following	1378	1420

Long Context Grok 4.20 (Non-Reasoning) leads

GPT-5.3 Chat: 42.6 (#120), Grok 4.20 (Non-Reasoning): 45.5 (#34)

Long Context benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Longer Query	1396	1437
CL-bench	—	22.2%
CL-bench Life	—	11.9%

Writing & Preference Grok 4.20 (Non-Reasoning) leads

GPT-5.3 Chat: 63.1 (#68), Grok 4.20 (Non-Reasoning): 65.7 (#44)

Writing & Preference benchmarks
Benchmark	GPT-5.3 Chat	Grok 4.20 (Non-Reasoning)
LMArena Text	1389	1451
LMArena Creative Writing	1355	1438
EQ-Bench Creative Writing	1690	1574
LMArena Multi-Turn	1412	1456

Frequently asked questions

Is GPT-5.3 Chat better than Grok 4.20 (Non-Reasoning)?

Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.6 to 42.8 on the Noometry Index.

Which is cheaper, GPT-5.3 Chat 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-5.3 Chat lists at $1.75 and $14.

Is GPT-5.3 Chat or Grok 4.20 (Non-Reasoning) better for coding?

They score almost the same on coding (41.4 vs 42.1); test both on your own repository before choosing.

Which has the bigger context window?

Grok 4.20 (Non-Reasoning) does, with 1M tokens against 128K.

How many benchmarks do GPT-5.3 Chat and Grok 4.20 (Non-Reasoning) share?

18 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Grok 4.20 (Non-Reasoning) has 46.