Precision levels
Answers round to 1/16" by default — the precision a framing crew or general contractor works to. In the iPhone app you can change it in Settings to 1/8", or down to 1/32" and 1/64" for cabinetmakers, finish carpenters, machinists, and anyone whose tolerances live in the smaller fractions.
Every answer formats to the level you chose. The rounding is done in the answer pipeline, not in the formula itself — so the math stays exact and the display matches what you can actually mark.
How the rounding works
Real numbers get split into integer feet, integer inches, and a fractional remainder. The remainder is rounded to the nearest unit of your chosen precision (1/8, 1/16, 1/32, or 1/64). The fraction is then reduced — 4/8 becomes 1/2, 2/16 becomes 1/8 — so what you read on screen is the simplest equivalent.
Anything smaller than half your chosen precision rounds to zero and disappears from the display. So at 1/16" precision, an answer of 43.7503 shows as 43-3/4" — same as 43.7501. The math is honest about what your tape can actually mark.
Imperial and metric
Both are first-class. If you set imperial as your default, metric questions still convert and answer (“2.4 meters in feet” → 7' 10-1/2"). If you set metric, the fractions go away and you get clean millimeter and centimeter results — but you can still ask in imperial and get a metric answer, or vice versa, mid-session.
Why it matters
Decimal-to-fraction mental math eats time and breeds errors. Every contractor doing it — twenty times a day, every day — is paying a tax. The whole point of the tape measure is that it reads in fractions. The whole point of Journeyman is that it speaks the same language.