The goal of this qualitative study was to understand the perspectives that adults with heart failure have about numerical concepts and instructions integral to HF self-care. We conducted one-on-one, semi-structured interviews with 30 patients with heart failure from December 2016 to March 2017 at Weill Cornell Internal Medicine Associates (WCIMA). The interviews elicited perspectives on numeracy across three domains of HF self-care: 1) monitoring weight; 2) maintaining a diet low in salt; and 3) monitoring blood pressure. Using grounded theory, five major themes emerged including: (1) Provider communication was inconsistent. (2) Information was often incorrectly applied. (3) Social and caregiver support is critical to understanding and carrying out numerical instructions associated with heart failure self-care. (4) Experience with other chronic diseases informed attitudes towards numerical concepts associated with heart failure and (5) Fear was a powerful barriers and facilitator with respect to mastering numerical concepts and carrying out numerical instructions. From the results and analysis, we developed a conceptual framework which postulates how numeracy influences self-care, from the patient’s perspective. Our findings suggest that many heart failure patients lack basic understanding and skills required for adequate self-management. Many rely on caregivers who may lack self-care training. Patient-provider communication, and heart failure-specific training of caregivers may be more important influences on successful self-management than individual patient numeracy.