GPT-4.1 mini vs GPT-OSS 20B

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

GPT-4.1 mini finishes one point ahead overall, 35 to 34. That is enough to call, but not enough to treat as a blowout. This matchup comes down to a few meaningful edges rather than one model dominating the board.

GPT-4.1 mini's sharpest advantage is in knowledge, where it averages 75.9 against 28.2. The single biggest benchmark swing on the page is MMLU, 87.5 to 31. GPT-OSS 20B does hit back in mathematics, so the answer changes if that is the part of the workload you care about most.

GPT-4.1 mini gives you the larger context window at 1M, compared with 128K for GPT-OSS 20B.

Quick Verdict

Pick GPT-4.1 mini if you want the stronger benchmark profile. GPT-OSS 20B only becomes the better choice if mathematics is the priority.

Knowledge

GPT-4.1 mini

GPT-4.1 mini

75.9

GPT-OSS 20B

28.2

87.5
MMLU
31
64.2
GPQA
30
-
SuperGPQA
28
-
OpenBookQA
26
-
MMLU-Pro
53
-
HLE
1

Coding

GPT-4.1 mini

GPT-4.1 mini

23.6

GPT-OSS 20B

16

23.6
SWE-bench Verified
14
-
HumanEval
23
-
LiveCodeBench
11

Mathematics

GPT-OSS 20B

GPT-4.1 mini

23.1

GPT-OSS 20B

33.6

23.1
AIME 2024
33
-
AIME 2023
31
-
AIME 2025
32
-
HMMT Feb 2023
27
-
HMMT Feb 2024
29
-
HMMT Feb 2025
28
-
BRUMO 2025
30
-
MATH-500
59

Reasoning

GPT-OSS 20B
-
SimpleQA
29
-
MuSR
27
-
BBH
62

Instruction Following

GPT-4.1 mini

GPT-4.1 mini

88.5

GPT-OSS 20B

67

88.5
IFEval
67

Multilingual

GPT-OSS 20B
-
MGSM
61

Frequently Asked Questions

Which is better, GPT-4.1 mini or GPT-OSS 20B?

GPT-4.1 mini is ahead overall, 35 to 34. The biggest single separator in this matchup is MMLU, where the scores are 87.5 and 31.

Which is better for knowledge tasks, GPT-4.1 mini or GPT-OSS 20B?

GPT-4.1 mini has the edge for knowledge tasks in this comparison, averaging 75.9 versus 28.2. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-4.1 mini or GPT-OSS 20B?

GPT-4.1 mini has the edge for coding in this comparison, averaging 23.6 versus 16. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, GPT-4.1 mini or GPT-OSS 20B?

GPT-OSS 20B has the edge for math in this comparison, averaging 33.6 versus 23.1. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-4.1 mini or GPT-OSS 20B?

GPT-4.1 mini has the edge for instruction following in this comparison, averaging 88.5 versus 67. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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