What do 'exit tread' and 'going depth' mean?

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Two important technical terms in staircase construction:

**Exit tread (Austrittsstufe):** The last, topmost step of a staircase. It forms the transition to the upper floor and finishes flush with the floor surface. The counterpart is the **entry tread (Antrittsstufe)** -- the first, bottom step.

**Going depth (Auftrittsbreite):** The horizontal depth of the tread surface, measured along the walking line. DIN 18065 specifies:
- **Primary staircases:** at least **26 cm**, recommended 29 cm
- **Secondary staircases:** at least **21 cm**
- **Comfort range:** 29--33 cm (particularly comfortable to walk on)

The going depth is calculated together with the riser height using the **stride formula**: 2 x riser height + going depth = 59--65 cm (an average stride). HTS calculates all dimensions using this formula to ensure an ergonomic and safe staircase.