An exact science is any field of science capable of accurate quantitative expression or precise predictions and rigorous methods of testing hypotheses, especially reproducible experiments involving quantifiable predictions and measurements. Mathematics, physics, chemistry, computer science as well as parts of biology, psychology, and the social sciences can be considered as exact sciences in this sense.

The term implies a dichotomy between these fields and others, such as the humanities. Related but not equivalent terms are hard science, pure science, and fundamental science.

• Demarcation problem