TaxCalcBench TY25
Professional Work · 2026-06-22
TaxCalcBench TY25 evaluates complete federal and state tax-return calculation from realistic taxpayer PDFs and companion structured data. Its headline strict score is the percentage of 50 cases for which every evaluated line on Form 1040, California Form 540, Illinois Form IL-1040, New York Form IT-201, or Virginia Form 760 exactly matches the expected return.
Top models (higher is better)
| Model | Score |
|---|---|
| Claude Fable 5.1 | 40.0 |
| Claude Opus 5.5 | 40.0 |
| GPT-6 Astra | 38.0 |
| GPT-6.1 Sol | 36.0 |
| GPT-5.6 Sol | 30.0 |
| Claude Fable 5 | 28.0 |
| GPT-6 Sol | 28.0 |
| GPT-5.5 | 26.0 |
| Claude Opus 5 | 22.0 |
| Muse Wonder | 22.0 |
| Opus 4.8 | 20.0 |
| Claude Sonnet 5.5 | 18.0 |
| GPT-6 Luna | 14.0 |
| Gemini 3.7 Flash | 12.0 |
| Gemini 3.6 Flash | 10.0 |
| Muse Spark 1.2 | 8.0 |
| Muse Spark 1.3 | 8.0 |
| Sonnet 5 | 6.0 |
| Kimi K3 | 6.0 |
| DeepSeek V4.1 Flash | 4.0 |
| Gemini 3.5 Flash | 4.0 |
| Gemini 3.8 Flash | 4.0 |
| Claude Haiku 5.5 | 2.0 |
| Gemini 3.1 Pro Preview | 2.0 |
| GLM-5.3 | 0.0 |
| Mistral Large 4 Preview | 0.0 |