Measuring a roof starts with safety first—use a sturdy ladder and harness if needed. Break the roof into simple rectangles or triangles, then measure each section's length and width from the eaves to the peak for angles. Multiply length by width for area, add them up, and account for the slope by multiplying by a pitch factor—typically around 1.1 to 1.3 for common pitches, or get the steeper slopes measured precisely. For a hip roof, add the triangular ends separately. Always double-check numbe… how to measure a roof 16