Phi-4 vs GPT-OSS 20B

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

Phi-4 is clearly ahead on the aggregate, 39 to 34. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Phi-4's sharpest advantage is in coding, where it averages 82.6 against 16. The single biggest benchmark swing on the page is HumanEval, 82.6 to 23.

GPT-OSS 20B gives you the larger context window at 128K, compared with 16K for Phi-4.

Quick Verdict

Pick Phi-4 if you want the stronger benchmark profile. GPT-OSS 20B only becomes the better choice if you need the larger 128K context window.

Knowledge

Phi-4

Phi-4

70.5

GPT-OSS 20B

28.2

84.8
MMLU
31
56.1
GPQA
30
-
SuperGPQA
28
-
OpenBookQA
26
-
MMLU-Pro
53
-
HLE
1

Coding

Phi-4

Phi-4

82.6

GPT-OSS 20B

16

82.6
HumanEval
23
-
SWE-bench Verified
14
-
LiveCodeBench
11

Mathematics

GPT-OSS 20B
-
AIME 2023
31
-
AIME 2024
33
-
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-OSS 20B
-
IFEval
67

Multilingual

Phi-4

Phi-4

80.6

GPT-OSS 20B

61

80.6
MGSM
61

Frequently Asked Questions

Which is better, Phi-4 or GPT-OSS 20B?

Phi-4 is ahead overall, 39 to 34. The biggest single separator in this matchup is HumanEval, where the scores are 82.6 and 23.

Which is better for knowledge tasks, Phi-4 or GPT-OSS 20B?

Phi-4 has the edge for knowledge tasks in this comparison, averaging 70.5 versus 28.2. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, Phi-4 or GPT-OSS 20B?

Phi-4 has the edge for coding in this comparison, averaging 82.6 versus 16. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Phi-4 or GPT-OSS 20B?

Phi-4 has the edge for multilingual tasks in this comparison, averaging 80.6 versus 61. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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