Half a millimeter is a difference you can see on a short beard; a quarter of a millimeter generally is not, and it is the specification that separates two otherwise similar trimmers.
The range on this site runs wide. The Braun AIO3545 gives 14 lengths from 3 to 21 mm (0.12 to 0.83 in) — steps of well over a millimeter. The BT5525 gives 40 lengths in half-millimeter steps. The BT9545 gives 52 in quarter-millimeter steps. The Remington MB5000 gives 17 from 0.4 to 18 mm (0.02 to 0.71 in).
At stubble lengths, the step size is what matters, because the difference between 1 mm (0.04 in) and 2 mm (0.08 in) is the difference between two looks.
At 10 mm (0.39 in) and above, it stops mattering. Nobody distinguishes 10 mm (0.39 in) from 10.5 mm (0.41 in) in a mirror.
So the useful question is where you actually sit. If you keep short stubble, fine steps are the specification worth paying for. If you keep a full beard and tidy the edges, a coarse ladder is enough and the money is better spent elsewhere.
One more thing to check: whether the setting locks. A wheel that shifts mid-pass turns a fine ladder into a liability, which is why the BT5525 publishes a lock.
Last reviewed August 22, 2026