Self-estimated intelligence is a quick way to assess people's conceptions of their own abilities. Furnham (2001) and colleagues have used this technique to make comparisons across culture and gender and different approaches to intelligence (such as g or Multiple Intelligences). This study seeks to build on past work in two ways. First, a large, diverse sample (N = 2309) enables the study of self-estimated intelligence across ethnicity. Second, one of the most prominent accepted intelligence theories is the Cattell–Horn–Carroll (CHC) theory. Can laypeople distinguish between general, fluid, and crystallized intelligence? This study finds evidence for a “modesty bias” in Hispanic Americans. In addition, fluid and crystallized intelligences may simply be seen as general intelligence (particularly by Caucasians and males).Highlights► Self-estimated intelligence (SEI) reflects what people think of their abilities. ► SEI and self-estimated crystallized (Gc) and fluid intelligence (Gf) measured. ► Large (N = 2599), diverse sample allows ethnicity comparisons. ► Females and Hispanic Americans self-rate lower than others (“modesty” bias). ► Laypeople (especially Caucasian males) do not distinguish between g, Gc, and Gf.