GPT-4.1 nano vs LFM2.5-1.2B-Instruct

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

GPT-4.1 nano is clearly ahead on the aggregate, 49 to 30. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-4.1 nano's sharpest advantage is in reasoning, where it averages 74.1 against 32.1. The single biggest benchmark swing on the page is MMLU, 80.1 to 26. LFM2.5-1.2B-Instruct does hit back in mathematics, so the answer changes if that is the part of the workload you care about most.

GPT-4.1 nano is also the more expensive model on tokens at $0.10 input / $0.40 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for LFM2.5-1.2B-Instruct. That is roughly Infinityx on output cost alone. GPT-4.1 nano gives you the larger context window at 1M, compared with 32K for LFM2.5-1.2B-Instruct.

Quick Verdict

Pick GPT-4.1 nano if you want the stronger benchmark profile. LFM2.5-1.2B-Instruct only becomes the better choice if mathematics is the priority or you want the cheaper token bill.

Agentic

GPT-4.1 nano

GPT-4.1 nano

47.4

LFM2.5-1.2B-Instruct

25.7

43
Terminal-Bench 2.0
22
62
BrowseComp
31
42
OSWorld-Verified
26

Coding

GPT-4.1 nano

GPT-4.1 nano

18

LFM2.5-1.2B-Instruct

7.2

18
SWE-bench Pro
6
Coming soon
HumanEval
14
Coming soon
SWE-bench Verified
9
Coming soon
LiveCodeBench
8

Multimodal & Grounded

GPT-4.1 nano

GPT-4.1 nano

59.3

LFM2.5-1.2B-Instruct

32.4

53
MMMU-Pro
27
67
OfficeQA Pro
39

Reasoning

GPT-4.1 nano

GPT-4.1 nano

74.1

LFM2.5-1.2B-Instruct

32.1

75
LongBench v2
34
73
MRCRv2
37
Coming soon
SimpleQA
24
Coming soon
MuSR
22
Coming soon
BBH
59

Knowledge

GPT-4.1 nano

GPT-4.1 nano

50.7

LFM2.5-1.2B-Instruct

26

80.1
MMLU
26
50.3
GPQA
25
51
FrontierScience
30
Coming soon
SuperGPQA
23
Coming soon
OpenBookQA
21
Coming soon
MMLU-Pro
50
Coming soon
HLE
1

Instruction Following

GPT-4.1 nano

GPT-4.1 nano

83.2

LFM2.5-1.2B-Instruct

80

83.2
IFEval
80

Multilingual

LFM2.5-1.2B-Instruct

GPT-4.1 nano

59

LFM2.5-1.2B-Instruct

60.7

59
MMLU-ProX
60
Coming soon
MGSM
62

Mathematics

LFM2.5-1.2B-Instruct

GPT-4.1 nano

9.8

LFM2.5-1.2B-Instruct

37

9.8
AIME 2024
26
Coming soon
AIME 2023
24
Coming soon
AIME 2025
25
Coming soon
HMMT Feb 2023
20
Coming soon
HMMT Feb 2024
22
Coming soon
HMMT Feb 2025
21
Coming soon
BRUMO 2025
23
Coming soon
MATH-500
54

Frequently Asked Questions

Which is better, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

GPT-4.1 nano is ahead overall, 49 to 30. The biggest single separator in this matchup is MMLU, where the scores are 80.1 and 26.

Which is better for knowledge tasks, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

GPT-4.1 nano has the edge for knowledge tasks in this comparison, averaging 50.7 versus 26. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

GPT-4.1 nano has the edge for coding in this comparison, averaging 18 versus 7.2. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

LFM2.5-1.2B-Instruct has the edge for math in this comparison, averaging 37 versus 9.8. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

GPT-4.1 nano has the edge for reasoning in this comparison, averaging 74.1 versus 32.1. Inside this category, LongBench v2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

GPT-4.1 nano has the edge for agentic tasks in this comparison, averaging 47.4 versus 25.7. Inside this category, BrowseComp is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

GPT-4.1 nano has the edge for multimodal and grounded tasks in this comparison, averaging 59.3 versus 32.4. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

GPT-4.1 nano has the edge for instruction following in this comparison, averaging 83.2 versus 80. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-4.1 nano or LFM2.5-1.2B-Instruct?

LFM2.5-1.2B-Instruct has the edge for multilingual tasks in this comparison, averaging 60.7 versus 59. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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