DeepSeek V3.1 (Reasoning) vs GPT-5 nano

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

DeepSeek V3.1 (Reasoning) is clearly ahead on the aggregate, 37 to 31. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5 nano gives you the larger context window at 400K, compared with 128K for DeepSeek V3.1 (Reasoning).

Quick Verdict

Pick DeepSeek V3.1 (Reasoning) 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

DeepSeek V3.1 (Reasoning)

31.7

GPT-5 nano

71.2

34
MMLU
-
33
GPQA
71.2
31
SuperGPQA
-
29
OpenBookQA
-
53
MMLU-Pro
-
10
HLE
-

Coding

DeepSeek V3.1 (Reasoning)
26
HumanEval
-
14
SWE-bench Verified
-
16
LiveCodeBench
-

Mathematics

GPT-5 nano

DeepSeek V3.1 (Reasoning)

36.6

GPT-5 nano

85.2

34
AIME 2023
-
36
AIME 2024
-
35
AIME 2025
85.2
30
HMMT Feb 2023
-
32
HMMT Feb 2024
-
31
HMMT Feb 2025
-
33
BRUMO 2025
-
62
MATH-500
-

Reasoning

DeepSeek V3.1 (Reasoning)
32
SimpleQA
-
30
MuSR
-
64
BBH
-

Instruction Following

DeepSeek V3.1 (Reasoning)
70
IFEval
-

Multilingual

DeepSeek V3.1 (Reasoning)
64
MGSM
-

Frequently Asked Questions

Which is better, DeepSeek V3.1 (Reasoning) or GPT-5 nano?

DeepSeek V3.1 (Reasoning) is ahead overall, 37 to 31. The biggest single separator in this matchup is AIME 2025, where the scores are 35 and 85.2.

Which is better for knowledge tasks, DeepSeek V3.1 (Reasoning) or GPT-5 nano?

GPT-5 nano has the edge for knowledge tasks in this comparison, averaging 71.2 versus 31.7. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for math, DeepSeek V3.1 (Reasoning) or GPT-5 nano?

GPT-5 nano has the edge for math in this comparison, averaging 85.2 versus 36.6. Inside this category, AIME 2025 is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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