Drill bit diameters and lengths are available in different sizes. These sizes are measured in both metric units and imperial units using a gauge. In order to ensure the right drill bit size, it should convert between fractions, inches, and millimeters. Using the drill bit chart guide below, you can convert the metric units, imperial units, and fractions correctly. It will help to select a drill bit and drill a hole precisely.
Drill Bit Size Chart
By following the above method, this table has been prepared with available drill bit sizes. You can see fractions, inches, and mm values for each drill bit size here.
| Fraction | inch | mm |
| 1⁄64 | 0.015625 | 0.396875 |
| 1⁄32 | 0.03125 | 0.79375 |
| 3⁄64 | 0.046875 | 1.190625 |
| 1⁄16 | 0.0625 | 1.5875 |
| 5⁄64 | 0.078125 | 1.984375 |
| 3⁄32 | 0.09375 | 2.38125 |
| 7⁄64 | 0.109375 | 2.778125 |
| 1⁄8 | 0.125 | 3.175 |
| 9⁄64 | 0.140625 | 3.571875 |
| 5⁄32 | 0.15625 | 3.96875 |
| 11⁄64 | 0.171875 | 4.365625 |
| 3⁄16 | 0.1875 | 4.7625 |
| 13⁄64 | 0.203125 | 5.159375 |
| 7⁄32 | 0.21875 | 5.55625 |
| 15⁄64 | 0.234375 | 5.953125 |
| 1⁄4 | 0.25 | 6.35 |
| 17⁄64 | 0.265625 | 6.746875 |
| 9⁄32 | 0.28125 | 7.14375 |
| 19⁄64 | 0.296875 | 7.540625 |
| 5⁄16 | 0.3125 | 7.9375 |
| 21⁄64 | 0.328125 | 8.334375 |
| 11⁄32 | 0.34375 | 8.73125 |
| 23⁄64 | 0.359375 | 9.128125 |
| 3⁄8 | 0.375 | 9.525 |
| 25⁄64 | 0.390625 | 9.921875 |
| 13⁄32 | 0.40625 | 10.31875 |
| 27⁄64 | 0.421875 | 10.715625 |
| 7⁄16 | 0.4375 | 11.1125 |
| 29⁄64 | 0.453125 | 11.509375 |
| 15⁄32 | 0.46875 | 11.90625 |
| 31⁄64 | 0.484375 | 12.303125 |
| 33⁄64 | 0.515625 | 13.096875 |
| 17⁄32 | 0.53125 | 13.49375 |
| 35⁄64 | 0.546875 | 13.890625 |
| 9⁄16 | 0.5625 | 14.2875 |
| 37⁄64 | 0.578125 | 14.684375 |
| 19⁄32 | 0.59375 | 15.08125 |
| 39⁄64 | 0.609375 | 15.478125 |
| 5⁄8 | 0.625 | 15.875 |
| 41⁄64 | 0.640625 | 16.271875 |
| 21⁄32 | 0.65625 | 16.66875 |
| 43⁄64 | 0.671875 | 17.065625 |
| 11⁄16 | 0.6875 | 17.4625 |
| 45⁄64 | 0.703125 | 17.859375 |
| 23⁄32 | 0.71875 | 18.25625 |
| 47⁄64 | 0.734375 | 18.653125 |
| 3⁄4 | 0.75 | 19.05 |
| 49⁄64 | 0.765625 | 19.446875 |
| 25⁄32 | 0.78125 | 19.84375 |
| 51⁄64 | 0.796875 | 20.240625 |
| 13⁄16 | 0.8125 | 20.6375 |
| 53⁄64 | 0.828125 | 21.034375 |
| 27⁄32 | 0.84375 | 21.43125 |
| 55⁄64 | 0.859375 | 21.828125 |
| 7⁄8 | 0.875 | 22.225 |
| 57⁄64 | 0.890625 | 22.621875 |
| 29⁄32 | 0.90625 | 23.01875 |
| 59⁄64 | 0.921875 | 23.415625 |
| 15⁄16 | 0.9375 | 23.8125 |
| 61⁄64 | 0.953125 | 24.209375 |
| 31⁄32 | 0.96875 | 24.60625 |
| 63⁄64 | 0.984375 | 25.003125 |
| 1 | 1 | 25.4 |
Drill Bit Size Conversion Methods
1. How to Convert Drill Bit mm to Inch?
When the drill bit diameter is available in mm, it can be converted into inches easily.
Mathematically,
1mm = 0.0393701 inches.
When you need to convert mm to inches, you have to multiply the mm value by 0.0393701
Ex – 15.875 mm × 0.0393701 = 0.625000 inches = 5/8″
2. How to Convert Drill Bit Inches to mm?
When you measure drill bit size in inches, you can convert it into mm using this method.
1 inch = 25.4mm
You can multiply by 25.4 of inches value when you convert that to mm.
Ex – 0.5 inches = 1/2″ = 0.5 inches × 25.4 = 12.7mm
Inches are really popular in the USA but, beyond that, mostly used SI units. So we have to interchange the metric units and imperial units.
The table below will introduce you to the fractions and decimals of inches in mm.
How to Measure Drill Bit Size?
Remembering everything is not easy. As for me I use this gauge to identify the drill bit size in inches and millimeters quickly. It is IRWIN drill gauge. You can measure 1/16″ to 1/2″ range of drill bits using that gauge.
Related Topics
