How we estimate it
We hold your lean mass constant, calculate the body weight at which your target body-fat % is reached, then apply your weekly loss rate to your current weight each week. Rates of roughly 0.5–1.0% of body weight per week are commonly recommended for preserving muscle while dieting (see Helms et al., 2014).
Default targets: 11% for men and 18% for women — the range where most people see clear ab definition.