Noometry

Model comparison

GPT-5.3 Chat vs Grok 4.3

Grok 4.3 is the stronger model overall, scoring 43.8 to 42.8 on the Noometry Index.

Last verified . 17 shared benchmarks.

GPT-5.3 Chat OpenAI

42.8

Rank #109 Confirmed

Grok 4.3 xAI

43.8

Rank #86 Confirmed

Summary

  • They share 17 benchmarks with published results for both. GPT-5.3 Chat scores higher in 3 categories and Grok 4.3 in 5 categories; 4 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Grok 4.3 leads 52.5 to 38.8.
  • Grok 4.3 is cheaper at $1.25 / $2.50 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
  • Grok 4.3 accepts more context: 1M tokens versus 128K.

Side by side

GPT-5.3 ChatGrok 4.3
ProviderOpenAIxAI
Noometry Index42.843.8
Released2026-03-032026-04-17
WeightsProprietaryProprietary
Context window128K1M
Max output16K30K
Input $ / M tokens$1.75$1.25
Output $ / M tokens$14$2.50
Results tracked1840

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Category by category

Coding Too close to call

GPT-5.3 Chat: 41.4 (#124), Grok 4.3: 41.6 (#121)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Coding14081415
LMArena WebDev—1357
SciCode—47.3%
WeirdML—49.9%
ALE-Bench—944.17

Agentic & Tool Use Not comparable

GPT-5.3 Chat: —, Grok 4.3: 27.7 (#99)

BenchmarkGPT-5.3 ChatGrok 4.3
GDP.pdf—8%
LMArena Search—1165
Vending-Bench 2—35.26

Reasoning Grok 4.3 leads

GPT-5.3 Chat: 28.5 (#102), Grok 4.3: 35.9 (#68)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Hard Prompts13991396
NYT Connections (extended)—55.2%
CritPt—8%
Chess Puzzles—25%
DTBench—90.7%
LMCA—38.3%
Epoch Capabilities Index—149.16
ForecastBench—60.3

Math Grok 4.3 leads

GPT-5.3 Chat: 38.2 (#142), Grok 4.3: 46.0 (#74)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Math13891388
FrontierMath (Tiers 1-3)—42.8%
FrontierMath Tier 4—14.6%
OTIS Mock AIME 2024-2025—93.3%
ProofBench—11%

Knowledge Grok 4.3 leads

GPT-5.3 Chat: 38.8 (#140), Grok 4.3: 52.5 (#62)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Expert13971385
GPQA Diamond—88.8%
SimpleQA Verified—33.2%

Multimodal Not comparable

GPT-5.3 Chat: —, Grok 4.3: 31.6 (#104)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Vision—1229
Blueprint-Bench 2—0%

Multilingual Too close to call

GPT-5.3 Chat: 50.3 (#124), Grok 4.3: 50.5 (#120)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Non-English13821385
LMArena Chinese14321422
LMArena French13971412
LMArena German13841395
LMArena Japanese13521379
LMArena Korean13461356
LMArena Russian14001399
LMArena Spanish13711398

Instruction Following Too close to call

GPT-5.3 Chat: 72.8 (#129), Grok 4.3: 72.1 (#140)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Instruction Following13781366

Long Context Too close to call

GPT-5.3 Chat: 42.6 (#120), Grok 4.3: 42.5 (#123)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Longer Query13961393

Writing & Preference GPT-5.3 Chat leads

GPT-5.3 Chat: 63.1 (#68), Grok 4.3: 58.5 (#118)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Text13891397
LMArena Creative Writing13551380
LMArena Multi-Turn14121406
EQ-Bench Creative Writing1690—
EQ-Bench 4—1075

Frequently asked questions

Is GPT-5.3 Chat better than Grok 4.3?

Grok 4.3 is the stronger model overall, scoring 43.8 to 42.8 on the Noometry Index.

Which is cheaper, GPT-5.3 Chat or Grok 4.3?

Grok 4.3 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 4.3 better for coding?

They score almost the same on coding (41.4 vs 41.6); test both on your own repository before choosing.

Which has the bigger context window?

Grok 4.3 does, with 1M tokens against 128K.

How many benchmarks do GPT-5.3 Chat and Grok 4.3 share?

17 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Grok 4.3 has 40.

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