This 16-question survey instrument is widely available on the internet. The original article on its development and validation can be found at:

Spreng, R. N., McKinnon, M. C., Mar, R. A., & Levine, B. (2009). The Toronto Empathy Questionnaire: Scale development and initial validation of a factor-analytic solution to multiple empathy measures. Journal of personality assessment, 91(1), 62-71. https://doi.org/10.1080/00223890802484381