Claude Sonnet 4.5 Nano on IFEval: score, rank and what it means
Claude Sonnet 4.5 Nano scores 82.2 on IFEval, placing it #269 of 600 models in the index. The benchmark average is 78.6 and the leader is Claude Opus 4.5 Pro at 96.1.
Score distribution
The chart shows the top 10 models on IFEval, with Claude Sonnet 4.5 Nano 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 | Claude Opus 4.5 Reasoning | Anthropic | 2000000 | $20.91 | 88.2 |
| 3 | GPT-5.2 Pro | OpenAI | 2000000 | $21.32 | 89.6 |
| 4 | GPT-5.2 Max | OpenAI | 1000000 | $21.39 | 89.2 |
| 5 | GPT-5.2 Reasoning | OpenAI | 1000000 | $20.98 | 87.5 |
| 6 | GPT-5.1 Pro | OpenAI | 200000 | $19.77 | 87.8 |
| 7 | Gemini 3 Pro Max | Google DeepMind | 2000000 | $20.57 | 87.9 |
| 8 | GPT-5.1 Reasoning | OpenAI | 400000 | $20.27 | 88.3 |
| 9 | Claude Opus 4.5 Max | Anthropic | 1000000 | $20.90 | 87.8 |
| 10 | o4 Reasoning | OpenAI | 1000000 | $19.69 | 87.5 |
What this score means
On IFEval, Claude Sonnet 4.5 Nano sits at #269 of 600. The leader, Claude Opus 4.5 Pro, scores 96.1, so the gap to the top is 13.9 points. The median model in this index scores 81.2, which puts Claude Sonnet 4.5 Nano above the midpoint.
Anthropic models average 88.3 on this benchmark. Claude Sonnet 4.5 Nano is 6.1 points below that provider line, so it is a weaker result than the average Anthropic model.
Among mid-range models, the average is 76.5. Claude Sonnet 4.5 Nano is 5.7 points above that group. This is the more useful comparison if you are shortlisting within the same tier rather than across the whole index.
Read a 82.2 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 $8.93 per million input tokens, Claude Sonnet 4.5 Nano is above the median input price of $4.00 across the 600 models scored on IFEval. 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 |
|---|---|---|---|---|
| Llama 3 DeepInfra Instruct | DeepInfra | 65536 | $3.84 | 75.5 |
| Llama 3 Lambda Base | Lambda | 8192 | $3.19 | 72.9 |
| Llama 3.1 | Meta AI | 200000 | $4.16 | 76.3 |
| Llama 4 Scout Base | Meta AI | 32768 | $3.95 | 75.3 |
| Claude Sonnet 4.5 Nano | Anthropic | 8192 | $8.93 | 72.0 |
| Nemotron 4 | NVIDIA | 65536 | $4.18 | 76.6 |
| Fusion Pro | OpenRouter | 65536 | $8.69 | 72.2 |
Other benchmarks for Claude Sonnet 4.5 Nano
| Benchmark | Score | Rank | Percentile | Relative |
|---|---|---|---|---|
| MMLU-Pro | 77.3 | 268 | 55th | |
| GPQA Diamond | 68.9 | 298 | 50th | |
| SWE-bench Verified | 61.2 | 295 | 51th | |
| HumanEval | 74.8 | 345 | 43th | |
| MATH-500 | 73.1 | 355 | 41th | |
| AIME 2025 | 64.2 | 353 | 41th | |
| LiveCodeBench | 61.2 | 359 | 40th | |
| TruthfulQA | 75.6 | 317 | 47th | |
| HellaSwag | 83.0 | 319 | 47th | |
| MMMU | 70.1 | 297 | 51th | |
| Arena Elo | 1364.3 | 334 | 44th |
FAQ
What score does Claude Sonnet 4.5 Nano get on IFEval?
Claude Sonnet 4.5 Nano scores 82.2 on IFEval in this index. The benchmark average is 78.6 and the top score is 96.1.
How does Claude Sonnet 4.5 Nano rank on IFEval?
It ranks #269 of 600 models, in the 55th percentile. The leader is Claude Opus 4.5 Pro at 96.1.
Is Claude Sonnet 4.5 Nano good at IFEval?
Yes, relative to the index: it is above the median and inside the top half of scores. The result should be read alongside its price and context window.
How is the IFEval score calculated?
IFEval is a instruction following 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 Claude Sonnet 4.5 Nano cost?
Claude Sonnet 4.5 Nano costs $8.93 per million input tokens and $36.88 per million output tokens.