For those who don’t have measuring equipment like a micrometer or digital calliper, try a drill gauge – inexpensive and easy to use.
It is a great gauge – steel, precise, durable. Markings are very clear and engraved on the back. Holes are marked in both inch fractions and millimeters. Plastic versions are cheaper but wear over time and such gauges are very inaccurate. Great tool.
If you are sick of going to get a 5mm drill and find something that looks like 5mm but not sure if it’s a 4.5mm or a 5.5mm nevermind a 4 or 6, Drill-Gauge Set is for you.
Woodstock D4141 isn’t high precision gauge, some small indexes are wrong. It is difficult to separate fractional and wire size drill bits that are only a few thousandths of an inch different in diameter. For better precision, you can use more expensive Irwin gauge
But gauges are made of non-cheap metal, very durable, and accuracy for medium and big diameter bits is good enough. If you use it for your DIY projects and don’t need ridiculously tight tolerances, it is your choice.