Noometry

Model comparison

GPT-5.3 Chat vs Grok 4.3

Grok 4.3 is the stronger model overall, scoring 43.6 to 42.1 on the Noometry Index.

Last verified . 17 shared benchmarks.

GPT-5.3 Chat OpenAI

42.1

Rank #109 Confirmed

Grok 4.3 xAI

43.6

Rank #80 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 38.2.
  • 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 Index42.143.6
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: 40.8 (#124), Grok 4.3: 41.3 (#117)

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: 27.6 (#93)

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: 27.3 (#105), Grok 4.3: 34.9 (#60)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Hard Prompts13991397
NYT Connections (extended)—55.2%
CritPt—8%
Chess Puzzles—25%
DTBench—90.7%
LMCA—38.3%
Epoch Capabilities Index—149.13
ForecastBench—60.3

Math Grok 4.3 leads

GPT-5.3 Chat: 35.4 (#146), Grok 4.3: 45.8 (#60)

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: 38.2 (#137), Grok 4.3: 52.5 (#57)

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 (#96)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Vision—1231
Blueprint-Bench 2—0%

Multilingual Too close to call

GPT-5.3 Chat: 50.5 (#119), Grok 4.3: 50.7 (#114)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Non-English13831385
LMArena Chinese14331423
LMArena French13981412
LMArena German13841395
LMArena Japanese13511379
LMArena Korean13471357
LMArena Russian14001399
LMArena Spanish13711402

Instruction Following Too close to call

GPT-5.3 Chat: 73.0 (#124), Grok 4.3: 72.3 (#135)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Instruction Following13781366

Long Context Too close to call

GPT-5.3 Chat: 42.6 (#115), Grok 4.3: 42.5 (#118)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Longer Query13961393

Writing & Preference GPT-5.3 Chat leads

GPT-5.3 Chat: 63.3 (#65), Grok 4.3: 58.6 (#112)

BenchmarkGPT-5.3 ChatGrok 4.3
LMArena Text13891397
LMArena Creative Writing13561380
LMArena Multi-Turn14131406
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 43.6 to 42.1 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 (40.8 vs 41.3); 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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