GPT-5.1 vs Z-1

Side-by-side benchmark comparison across knowledge, coding, math, and reasoning.

Quick Verdict

GPT-5.1 wins overall with a score of 76 vs 43 (33 point difference).GPT-5.1 wins 4 out of 4 categories.

Knowledge

GPT-5.1

GPT-5.1

94

Z-1

49.8

97
MMLU
52
95
GPQA
51
93
SuperGPQA
49
91
OpenBookQA
47

Coding

GPT-5.1

GPT-5.1

89

Z-1

44

89
HumanEval
44

Mathematics

GPT-5.1

GPT-5.1

97.1

Z-1

51

99
AIME 2023
52
99
AIME 2024
54
98
AIME 2025
53
95
HMMT Feb 2023
48
97
HMMT Feb 2024
50
96
HMMT Feb 2025
49
96
BRUMO 2025
51

Reasoning

GPT-5.1

GPT-5.1

92

Z-1

49

93
SimpleQA
50
91
MuSR
48

Frequently Asked Questions

Which is better, GPT-5.1 or Z-1?

GPT-5.1 scores higher overall with 76 vs 43, a difference of 33 points across all benchmarks.

Which is better for knowledge tasks, GPT-5.1 or Z-1?

GPT-5.1 leads in knowledge tasks with an average score of 94 vs 49.8.

Which is better for coding, GPT-5.1 or Z-1?

GPT-5.1 leads in coding with an average score of 89 vs 44.

Which is better for math, GPT-5.1 or Z-1?

GPT-5.1 leads in math with an average score of 97.1 vs 51.

Which is better for reasoning, GPT-5.1 or Z-1?

GPT-5.1 leads in reasoning with an average score of 92 vs 49.