Claude Sonnet 4.5 on IFEval: score, rank and what it means
Claude Sonnet 4.5 scores 91.1 on IFEval, placing it #50 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 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 sits at #50 of 600. The leader, Claude Opus 4.5 Pro, scores 96.1, so the gap to the top is 5.0 points. The median model in this index scores 81.2, which puts Claude Sonnet 4.5 above the midpoint.
Anthropic models average 88.3 on this benchmark. Claude Sonnet 4.5 is 2.8 points above that provider line, so it is a stronger result than the average Anthropic model.
Among frontier models, the average is 92.0. Claude Sonnet 4.5 is 0.9 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 91.1 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 $17.84 per million input tokens, Claude Sonnet 4.5 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 |
|---|---|---|---|---|
| DeepSeek-V3.2 Instruct | DeepSeek | 128000 | $5.91 | 83.7 |
| Gemini 2.5 Pro Max | Google DeepMind | 200000 | $16.94 | 84.8 |
| Gemini 3 Flash Max | Google DeepMind | 1000000 | $17.43 | 85.0 |
| Grok 4 Pro | xAI | 1000000 | $19.00 | 85.4 |
| Claude Sonnet 4.5 | Anthropic | 400000 | $17.84 | 86.0 |
| Grok 4 Turbo | xAI | 1000000 | $19.21 | 86.7 |
| o4 Max | OpenAI | 2000000 | $19.51 | 86.2 |
Other benchmarks for Claude Sonnet 4.5
| Benchmark | Score | Rank | Percentile | Relative |
|---|---|---|---|---|
| MMLU-Pro | 88.0 | 17 | 97th | |
| GPQA Diamond | 82.6 | 23 | 96th | |
| SWE-bench Verified | 74.2 | 50 | 92th | |
| HumanEval | 92.7 | 12 | 98th | |
| MATH-500 | 87.0 | 76 | 87th | |
| AIME 2025 | 86.3 | 25 | 96th | |
| LiveCodeBench | 82.5 | 19 | 97th | |
| TruthfulQA | 87.2 | 33 | 95th | |
| HellaSwag | 93.0 | 23 | 96th | |
| MMMU | 80.9 | 44 | 93th | |
| Arena Elo | 1478.2 | 21 | 97th |
FAQ
What score does Claude Sonnet 4.5 get on IFEval?
Claude Sonnet 4.5 scores 91.1 on IFEval in this index. The benchmark average is 78.6 and the top score is 96.1.
How does Claude Sonnet 4.5 rank on IFEval?
It ranks #50 of 600 models, in the 92nd percentile. The leader is Claude Opus 4.5 Pro at 96.1.
Is Claude Sonnet 4.5 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 cost?
Claude Sonnet 4.5 costs $17.84 per million input tokens and $70.50 per million output tokens.