<p>It is well-known that motivation matters for math and science learning, but most empirical motivation researchers do not directly examine how students consciously weigh multiple, competing, motivational beliefs when making academic choices. This study aimed to examine <i>motivational weighing</i> among high school students who were predominantly from racially marginalized backgrounds (<i>N</i> = 428). In an online survey, 9th and 10th grade students from 12 schools answered open-ended questions about how they weighed the benefits and challenges of completing mathematics and science coursework. We evaluated (a) what motivational factors (operationalized in terms of situated expectancy-value theory) students most often reported weighing, (b) what conclusions students drew about weighing benefits against challenges, and (c) how conclusions about weighing were associated with students’ course grades, future course-taking intentions, and future career intentions across one academic year. Results showed that most students discussed course benefits in terms of utility-value-related beliefs and challenges in terms of competence-related or cost-related beliefs. Yet despite most students discussing similar benefits and challenges, only about half of the students thought that the benefits were worth the challenges, and there was variability in how students explained the ways that they weighed benefits against challenges. Further, students who perceived that benefits outweighed challenges (compared to those who thought challenges outweighed benefits) reported higher future mathematics and science course-taking intentions and had higher science grades at the end of the year. Patterns held even when controlling for the actual challenges and benefits that students reported considering, as well as initial grades and course-taking intentions. Results illustrate that motivational weighing is an important process in academic decision-making that could be studied further in contemporary motivation research.</p>