Claude Opus 4.5 Reasoning on IFEval: score, rank and what it means
Claude Opus 4.5 Reasoning scores 95.9 on IFEval, placing it #2 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 Opus 4.5 Reasoning 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 Opus 4.5 Reasoning sits at #2 of 600. The leader, Claude Opus 4.5 Pro, scores 96.1, so the gap to the top is 0.2 points. The median model in this index scores 81.2, which puts Claude Opus 4.5 Reasoning above the midpoint.
Anthropic models average 88.3 on this benchmark. Claude Opus 4.5 Reasoning is 7.6 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 Opus 4.5 Reasoning is 3.9 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 95.9 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 $20.91 per million input tokens, Claude Opus 4.5 Reasoning 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 |
|---|---|---|---|---|
| Claude Opus 4.5 Pro | Anthropic | 200000 | $20.98 | 89.1 |
| Claude Opus 4.5 Reasoning | Anthropic | 2000000 | $20.91 | 88.2 |
| GPT-5.2 Pro | OpenAI | 2000000 | $21.32 | 89.6 |
| GPT-5.2 Max | OpenAI | 1000000 | $21.39 | 89.2 |
| GPT-5.2 Reasoning | OpenAI | 1000000 | $20.98 | 87.5 |
| GPT-5.1 Pro | OpenAI | 200000 | $19.77 | 87.8 |
Other benchmarks for Claude Opus 4.5 Reasoning
| Benchmark | Score | Rank | Percentile | Relative |
|---|---|---|---|---|
| MMLU-Pro | 90.7 | 4 | 99th | |
| GPQA Diamond | 82.6 | 22 | 96th | |
| SWE-bench Verified | 79.5 | 10 | 98th | |
| HumanEval | 92.1 | 19 | 97th | |
| MATH-500 | 91.6 | 30 | 95th | |
| AIME 2025 | 88.9 | 10 | 98th | |
| LiveCodeBench | 81.8 | 27 | 96th | |
| TruthfulQA | 89.0 | 11 | 98th | |
| HellaSwag | 93.8 | 14 | 98th | |
| MMMU | 84.6 | 7 | 99th | |
| Arena Elo | 1497.5 | 4 | 99th |
FAQ
What score does Claude Opus 4.5 Reasoning get on IFEval?
Claude Opus 4.5 Reasoning scores 95.9 on IFEval in this index. The benchmark average is 78.6 and the top score is 96.1.
How does Claude Opus 4.5 Reasoning rank on IFEval?
It ranks #2 of 600 models, in the 100th percentile. The leader is Claude Opus 4.5 Pro at 96.1.
Is Claude Opus 4.5 Reasoning 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 Opus 4.5 Reasoning cost?
Claude Opus 4.5 Reasoning costs $20.91 per million input tokens and $108.13 per million output tokens.