Although it depends on the drilling angle, this is generally a good guideline.

Skid-type 1.5-metric-ton-class core drill = 30–50 cm

Skid-type 2.5-metric-ton-class core drilling rig = 30–60 cm

Lightweight drilling machines (such as spring drills) = 20–30 cm

Crawler-type core drill = -20 to -30 cm (soil foundation)