Grok Code Fast 1 vs GPT-5 nano

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

Grok Code Fast 1 is clearly ahead on the aggregate, 58 to 31. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5 nano is the reasoning model in the pair, while Grok Code Fast 1 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. GPT-5 nano gives you the larger context window at 400K, compared with 256K for Grok Code Fast 1.

Quick Verdict

Pick Grok Code Fast 1 if you want the stronger benchmark profile. GPT-5 nano only becomes the better choice if mathematics is the priority or you need the larger 400K context window.

Knowledge

GPT-5 nano

Grok Code Fast 1

53.2

GPT-5 nano

71.2

64
MMLU
-
63
GPQA
71.2
61
SuperGPQA
-
59
OpenBookQA
-
65
MMLU-Pro
-
7
HLE
-

Coding

Grok Code Fast 1
60
HumanEval
-
31
SWE-bench Verified
-
24
LiveCodeBench
-

Mathematics

GPT-5 nano

Grok Code Fast 1

64.3

GPT-5 nano

85.2

64
AIME 2023
-
66
AIME 2024
-
65
AIME 2025
85.2
60
HMMT Feb 2023
-
62
HMMT Feb 2024
-
61
HMMT Feb 2025
-
63
BRUMO 2025
-
73
MATH-500
-

Reasoning

Grok Code Fast 1
61
SimpleQA
-
59
MuSR
-
75
BBH
-

Instruction Following

Grok Code Fast 1
79
IFEval
-

Multilingual

Grok Code Fast 1
75
MGSM
-

Frequently Asked Questions

Which is better, Grok Code Fast 1 or GPT-5 nano?

Grok Code Fast 1 is ahead overall, 58 to 31. The biggest single separator in this matchup is AIME 2025, where the scores are 65 and 85.2.

Which is better for knowledge tasks, Grok Code Fast 1 or GPT-5 nano?

GPT-5 nano has the edge for knowledge tasks in this comparison, averaging 71.2 versus 53.2. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for math, Grok Code Fast 1 or GPT-5 nano?

GPT-5 nano has the edge for math in this comparison, averaging 85.2 versus 64.3. Inside this category, AIME 2025 is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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