Zephyr 1.5B on AIME 2025: score, rank and what it means
Zephyr 1.5B scores 17.6 on AIME 2025, placing it #599 of 600 models in the index. The benchmark average is 63.6 and the leader is Claude Opus 4.5 Pro at 91.4.
Score distribution
The chart shows the top 10 models on AIME 2025, with Zephyr 1.5B highlighted. Longer bars mean higher scores.
Top 10 leaderboard
| # | Model | Provider | Context | Input / 1M | Avg score |
|---|---|---|---|---|---|
| 1 | Claude Opus 4.5 Pro | Anthropic | 200000 | $20.98 | 89.1 |
| 2 | GPT-5.2 Pro | OpenAI | 2000000 | $21.32 | 89.6 |
| 3 | GPT-5.1 Pro | OpenAI | 200000 | $19.77 | 87.8 |
| 4 | GPT-5.2 | OpenAI | 2000000 | $19.71 | 88.0 |
| 5 | o4 Reasoning | OpenAI | 1000000 | $19.69 | 87.5 |
| 6 | o4 Pro | OpenAI | 1000000 | $19.37 | 87.3 |
| 7 | Claude Opus 4.5 | Anthropic | 400000 | $19.42 | 87.7 |
| 8 | Gemini 3 Pro Max | Google DeepMind | 2000000 | $20.57 | 87.9 |
| 9 | Claude Opus 4.5 Max | Anthropic | 1000000 | $20.90 | 87.8 |
| 10 | Claude Opus 4.5 Reasoning | Anthropic | 2000000 | $20.91 | 88.2 |
What this score means
On AIME 2025, Zephyr 1.5B sits at #599 of 600. The leader, Claude Opus 4.5 Pro, scores 91.4, so the gap to the top is 73.8 points. The median model in this index scores 67.6, which puts Zephyr 1.5B below the midpoint.
Hugging Face models average 41.0 on this benchmark. Zephyr 1.5B is 23.4 points below that provider line, so it is a weaker result than the average Hugging Face model.
Among small open-weight models, the average is 41.6. Zephyr 1.5B is 24.0 points below that group. This is the more useful comparison if you are shortlisting within the same tier rather than across the whole index.
Read a 17.6 as a relative signal, not an absolute guarantee. Benchmark scores depend on prompt format, evaluation harness and contamination controls. Use this page to narrow the shortlist, then test the model on your own data.
Price context
At $0.10 per million input tokens, Zephyr 1.5B is below the median input price of $4.00 across the 600 models scored on AIME 2025. The models immediately around it in the ranking are shown below so you can compare score and price together.
| Model | Provider | Context | Input / 1M | Avg score |
|---|---|---|---|---|
| StableLM 2 1.5B | Stability AI | 16384 | $0.13 | 38.3 |
| Pythia 7B | EleutherAI | 8192 | $0.10 | 40.7 |
| SmolLM3 1.5B | Hugging Face | 8192 | $0.04 | 36.8 |
| GPT-NeoX 1.5B | EleutherAI | 32768 | $0.06 | 36.4 |
| Zephyr 1.5B | Hugging Face | 32768 | $0.10 | 38.0 |
| Pythia 1.5B | EleutherAI | 4096 | $0.10 | 35.8 |
Other benchmarks for Zephyr 1.5B
| Benchmark | Score | Rank | Percentile | Relative |
|---|---|---|---|---|
| MMLU-Pro | 48.3 | 596 | 1th | |
| GPQA Diamond | 35.2 | 595 | 1th | |
| SWE-bench Verified | 18.7 | 598 | 1th | |
| HumanEval | 41.2 | 596 | 1th | |
| MATH-500 | 35.5 | 598 | 1th | |
| LiveCodeBench | 22.3 | 596 | 1th | |
| IFEval | 52.6 | 594 | 1th | |
| TruthfulQA | 47.2 | 596 | 1th | |
| HellaSwag | 60.4 | 596 | 1th | |
| MMMU | 39.1 | 596 | 1th | |
| Arena Elo | 1105.1 | 597 | 1th |
FAQ
What score does Zephyr 1.5B get on AIME 2025?
Zephyr 1.5B scores 17.6 on AIME 2025 in this index. The benchmark average is 63.6 and the top score is 91.4.
How does Zephyr 1.5B rank on AIME 2025?
It ranks #599 of 600 models, in the 1st percentile. The leader is Claude Opus 4.5 Pro at 91.4.
Is Zephyr 1.5B good at AIME 2025?
It is below the median for this benchmark, so test it carefully before relying on it for this capability. The result should be read alongside its price and context window.
How is the AIME 2025 score calculated?
AIME 2025 is a mathematics benchmark. Scores in this index are modelled estimates on a 0–100 scale (or Elo for Arena), derived from capability tier and benchmark difficulty. They are not official leaderboard results.
What does Zephyr 1.5B cost?
Zephyr 1.5B costs $0.10 per million input tokens and $0.51 per million output tokens.