Identify an Unmarked Drill Bit
A free tool for identifying a drill bit whose markings have worn off. Lay the bit on a calibrated on-screen ruler, or print a 1:1 paper gauge, and read its diameter as a metric size or a fractional-inch size — no caliper needed.
How to identify a drill bit
1
Pick a mode
Choose "Measure on screen" for a calibrated ruler, or "Print a gauge" to download a paper sheet.
2
Calibrate or print at 100%
On screen, match the blue rectangle to a bank card. On paper, print at Actual size and check the 50 mm bar.
3
Measure and read
Lay the drill bit across the scale at its widest point; the tool shows the nearest metric and inch size.
Read a drill bit's diameter in metric and inches
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