Tiny Online Tools
A drill file is the part of a fabrication package easiest to get wrong silently — a tool table that looks fine but has the wrong units, or a hole count that doesn't match what the design actually needs. This tool reads a single Excellon (.drl/.txt/.nc) file and shows exactly what's in it, with nothing inferred beyond the file itself.
Drop in the file and it parses the tool table (each tool's code and diameter), then walks every hit to count holes and slots per tool. Diameters are shown in both millimetres and inches, since fab houses and CAM tools disagree on which one a given file uses. A 2D plot renders every hole at its real position, sized to its tool's diameter and coloured by tool, so a misplaced or missing hole is visible at a glance rather than buried in a column of numbers.
Plating is reported honestly. Some Excellon files declare plated vs non-plated per tool; most don't — that distinction is usually made by shipping two separate files instead, one per class. When a file doesn't declare it, this tool says so plainly rather than guessing one way or the other.
One parsing quirk worth knowing: the Excellon format uses a standalone % line to mark the end of its header, and real files — including ones straight out of KiCad — sometimes carry more than one such line. The parser this tool is built on stops cold at the first unrecognised one, so every stray % is stripped before parsing; nothing else about the file is touched. Everything happens in your browser — the file is never uploaded anywhere.