Model comparison

GLM-5.1 vs GPT-5.3 Chat

GLM-5.1 is the stronger model overall, scoring 47.8 to 42.8 on the Noometry Index.

Last verified . 18 shared benchmarks.

GLM-5.1 Z.ai (Zhipu)

47.8

Rank #59 Confirmed

GPT-5.3 Chat OpenAI

42.8

Rank #109 Confirmed

Summary

  • They share 18 benchmarks with published results for both. GLM-5.1 scores higher in 8 categories and GPT-5.3 Chat in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where GLM-5.1 leads 54.9 to 38.8.
  • GLM-5.1 is cheaper at $1.40 / $4.40 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
  • GLM-5.1 accepts more context: 200K tokens versus 128K.
  • GLM-5.1 has downloadable open weights; the other is API-only.

Side by side

GLM-5.1 and GPT-5.3 Chat specifications
GLM-5.1GPT-5.3 Chat
ProviderZ.ai (Zhipu)OpenAI
Noometry Index47.842.8
Released2026-04-072026-03-03
WeightsOpenProprietary
Context window200K128K
Max output131K16K
Input $ / M tokens$1.40$1.75
Output $ / M tokens$4.40$14
Results tracked4118

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Category by category

Coding GLM-5.1 leads

GLM-5.1: 48.7 (#55), GPT-5.3 Chat: 41.4 (#124)

Coding benchmarks
BenchmarkGLM-5.1GPT-5.3 Chat
LMArena Coding14851408
SWE-bench Verified74.2%—
LMArena WebDev1508—
SciCode43.8%—
WeirdML57.1%—
ALE-Bench887.1—

Agentic & Tool Use Not comparable

GLM-5.1: 24.9 (#113), GPT-5.3 Chat: —

Agentic & Tool Use benchmarks
BenchmarkGLM-5.1GPT-5.3 Chat
APEX-Agents40.9%—
ExploitBench18.1%—
GBAEval0%—
Vending-Bench 25,634—

Reasoning GLM-5.1 leads

GLM-5.1: 39.1 (#60), GPT-5.3 Chat: 28.5 (#102)

Reasoning benchmarks
BenchmarkGLM-5.1GPT-5.3 Chat
LMArena Hard Prompts14721399
SimpleBench55.1%—
NYT Connections (extended)77.7%—
CritPt4.6%—
Chess Puzzles19%—
Thematic Generalization69.8%—
Epoch Capabilities Index149.84—

Math GLM-5.1 leads

GLM-5.1: 49.7 (#60), GPT-5.3 Chat: 38.2 (#142)

Knowledge GLM-5.1 leads

GLM-5.1: 54.9 (#50), GPT-5.3 Chat: 38.8 (#140)

Knowledge benchmarks
BenchmarkGLM-5.1GPT-5.3 Chat
LMArena Expert14761397
GPQA Diamond89.9%—
SimpleQA Verified34%—

Multilingual GLM-5.1 leads

GLM-5.1: 55.0 (#36), GPT-5.3 Chat: 50.3 (#124)

Multilingual benchmarks
BenchmarkGLM-5.1GPT-5.3 Chat
LMArena Non-English14471382
LMArena Chinese15151432
LMArena French14741397
LMArena German14651384
LMArena Japanese14341352
LMArena Korean14181346
LMArena Russian14541400
LMArena Spanish14691371

Instruction Following GLM-5.1 leads

GLM-5.1: 76.3 (#42), GPT-5.3 Chat: 72.8 (#129)

Instruction Following benchmarks
BenchmarkGLM-5.1GPT-5.3 Chat
LMArena Instruction Following14511378

Long Context GLM-5.1 leads

GLM-5.1: 44.9 (#53), GPT-5.3 Chat: 42.6 (#120)

Long Context benchmarks
BenchmarkGLM-5.1GPT-5.3 Chat
LMArena Longer Query14661396

Writing & Preference GLM-5.1 leads

GLM-5.1: 66.9 (#31), GPT-5.3 Chat: 63.1 (#68)

Writing & Preference benchmarks
BenchmarkGLM-5.1GPT-5.3 Chat
LMArena Text14611389
LMArena Creative Writing14531355
EQ-Bench Creative Writing15921690
LMArena Multi-Turn14721412

Frequently asked questions

Is GLM-5.1 better than GPT-5.3 Chat?

GLM-5.1 is the stronger model overall, scoring 47.8 to 42.8 on the Noometry Index.

Which is cheaper, GLM-5.1 or GPT-5.3 Chat?

GLM-5.1 is cheaper. It lists at $1.40 per million input tokens and $4.40 per million output tokens; GPT-5.3 Chat lists at $1.75 and $14.

Is GLM-5.1 or GPT-5.3 Chat better for coding?

GLM-5.1 scores higher on coding benchmarks: 48.7 versus 41.4 in the Noometry coding category.

Which has the bigger context window?

GLM-5.1 does, with 200K tokens against 128K.

How many benchmarks do GLM-5.1 and GPT-5.3 Chat share?

18 benchmarks have published results for both models. GLM-5.1 has 41 scored results on Noometry and GPT-5.3 Chat has 18.

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