Claude Opus 4.5 Nano on TruthfulQA: score, rank and what it means
Claude Opus 4.5 Nano scores 78.1 on TruthfulQA, placing it #252 of 600 models in the index. The benchmark average is 73.6 and the leader is GPT-5.1 Max at 91.1.
Score distribution
The chart shows the top 10 models on TruthfulQA, with Claude Opus 4.5 Nano highlighted. Longer bars mean higher scores.
Top 10 leaderboard
| # | Model | Provider | Context | Input / 1M | Avg score |
|---|---|---|---|---|---|
| 1 | GPT-5.1 Max | OpenAI | 2000000 | $20.50 | 87.9 |
| 2 | Gemini 3 Pro Reasoning | Google DeepMind | 200000 | $19.69 | 87.5 |
| 3 | GPT-5.1 Reasoning | OpenAI | 400000 | $20.27 | 88.3 |
| 4 | GPT-5.2 Pro | OpenAI | 2000000 | $21.32 | 89.6 |
| 5 | GPT-5.2 | OpenAI | 2000000 | $19.71 | 88.0 |
| 6 | Gemini 3 Pro Max | Google DeepMind | 2000000 | $20.57 | 87.9 |
| 7 | Grok 4 Reasoning | xAI | 2000000 | $19.67 | 87.8 |
| 8 | Qwen3-Max Max | Alibaba Cloud | 400000 | $18.53 | 85.9 |
| 9 | GPT-5.1 | OpenAI | 2000000 | $19.01 | 86.0 |
| 10 | GPT-5.1 Turbo | OpenAI | 2000000 | $19.19 | 86.1 |
What this score means
On TruthfulQA, Claude Opus 4.5 Nano sits at #252 of 600. The leader, GPT-5.1 Max, scores 91.1, so the gap to the top is 13.0 points. The median model in this index scores 76.3, which puts Claude Opus 4.5 Nano above the midpoint.
Anthropic models average 82.9 on this benchmark. Claude Opus 4.5 Nano is 4.8 points below that provider line, so it is a weaker result than the average Anthropic model.
Among multimodal models, the average is 80.1. Claude Opus 4.5 Nano is 2.0 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 78.1 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 $9.38 per million input tokens, Claude Opus 4.5 Nano is above the median input price of $4.00 across the 600 models scored on TruthfulQA. 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 |
|---|---|---|---|---|
| Codestral Instruct | Mistral AI | 65536 | $4.01 | 75.1 |
| GPT-5.2 Nano | OpenAI | 128000 | $9.73 | 73.5 |
| Llama 3 DeepInfra | DeepInfra | 128000 | $3.67 | 74.0 |
| Phi-4 Instruct | Microsoft | 128000 | $3.79 | 75.3 |
| Claude Opus 4.5 Nano | Anthropic | 32768 | $9.38 | 73.3 |
| GPT-5.1 Nano | OpenAI | 32768 | $9.56 | 74.1 |
| Sonar Reasoning | Perplexity | 200000 | $11.48 | 76.2 |
Other benchmarks for Claude Opus 4.5 Nano
| Benchmark | Score | Rank | Percentile | Relative |
|---|---|---|---|---|
| MMLU-Pro | 76.1 | 300 | 50th | |
| GPQA Diamond | 69.4 | 281 | 53th | |
| SWE-bench Verified | 62.2 | 273 | 55th | |
| HumanEval | 75.5 | 334 | 44th | |
| MATH-500 | 77.2 | 272 | 55th | |
| AIME 2025 | 71.4 | 229 | 62th | |
| LiveCodeBench | 65.0 | 293 | 51th | |
| IFEval | 79.7 | 337 | 44th | |
| HellaSwag | 82.1 | 344 | 43th | |
| MMMU | 69.2 | 322 | 46th | |
| Arena Elo | 1373.3 | 305 | 49th |
FAQ
What score does Claude Opus 4.5 Nano get on TruthfulQA?
Claude Opus 4.5 Nano scores 78.1 on TruthfulQA in this index. The benchmark average is 73.6 and the top score is 91.1.
How does Claude Opus 4.5 Nano rank on TruthfulQA?
It ranks #252 of 600 models, in the 58th percentile. The leader is GPT-5.1 Max at 91.1.
Is Claude Opus 4.5 Nano good at TruthfulQA?
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 TruthfulQA score calculated?
TruthfulQA is a safety 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 Nano cost?
Claude Opus 4.5 Nano costs $9.38 per million input tokens and $36.06 per million output tokens.