Drill bit size chart (free printable PDF)
Every common drill bit size — fractional inch, decimal inch, and millimetre — in order from smallest to largest. The everyday reference for matching a bit across inches and mm — download the free printable PDF or print it from the page.
Drill bit size chart
| Fraction | Decimal inch | mm |
|---|---|---|
| 1/64" | 0.0156" | 0.4 |
| 1/32" | 0.0313" | 0.79 |
| 3/64" | 0.0469" | 1.19 |
| 1/16" | 0.0625" | 1.59 |
| 5/64" | 0.0781" | 1.98 |
| 3/32" | 0.0938" | 2.38 |
| 7/64" | 0.1094" | 2.78 |
| 1/8" | 0.125" | 3.18 |
| 9/64" | 0.1406" | 3.57 |
| 5/32" | 0.1563" | 3.97 |
| 11/64" | 0.1719" | 4.37 |
| 3/16" | 0.1875" | 4.76 |
| 13/64" | 0.2031" | 5.16 |
| 7/32" | 0.2188" | 5.56 |
| 15/64" | 0.2344" | 5.95 |
| 1/4" | 0.25" | 6.35 |
| 17/64" | 0.2656" | 6.75 |
| 9/32" | 0.2813" | 7.14 |
| 19/64" | 0.2969" | 7.54 |
| 5/16" | 0.3125" | 7.94 |
| 21/64" | 0.3281" | 8.33 |
| 11/32" | 0.3438" | 8.73 |
| 23/64" | 0.3594" | 9.13 |
| 3/8" | 0.375" | 9.52 |
| 25/64" | 0.3906" | 9.92 |
| 13/32" | 0.4063" | 10.32 |
| 27/64" | 0.4219" | 10.72 |
| 7/16" | 0.4375" | 11.11 |
| 29/64" | 0.4531" | 11.51 |
| 15/32" | 0.4688" | 11.91 |
| 31/64" | 0.4844" | 12.3 |
| 1/2" | 0.5" | 12.7 |
| 33/64" | 0.5156" | 13.1 |
| 17/32" | 0.5313" | 13.49 |
| 35/64" | 0.5469" | 13.89 |
| 9/16" | 0.5625" | 14.29 |
| 37/64" | 0.5781" | 14.68 |
| 19/32" | 0.5938" | 15.08 |
| 39/64" | 0.6094" | 15.48 |
| 5/8" | 0.625" | 15.88 |
| 41/64" | 0.6406" | 16.27 |
| 21/32" | 0.6563" | 16.67 |
| 43/64" | 0.6719" | 17.07 |
| 11/16" | 0.6875" | 17.46 |
| 45/64" | 0.7031" | 17.86 |
| 23/32" | 0.7188" | 18.26 |
| 47/64" | 0.7344" | 18.65 |
| 3/4" | 0.75" | 19.05 |
| 49/64" | 0.7656" | 19.45 |
| 25/32" | 0.7813" | 19.84 |
| 51/64" | 0.7969" | 20.24 |
| 13/16" | 0.8125" | 20.64 |
| 53/64" | 0.8281" | 21.03 |
| 27/32" | 0.8438" | 21.43 |
| 55/64" | 0.8594" | 21.83 |
| 7/8" | 0.875" | 22.23 |
| 57/64" | 0.8906" | 22.62 |
| 29/32" | 0.9063" | 23.02 |
| 59/64" | 0.9219" | 23.42 |
| 15/16" | 0.9375" | 23.81 |
| 61/64" | 0.9531" | 24.21 |
| 31/32" | 0.9688" | 24.61 |
| 63/64" | 0.9844" | 25 |
| 1" | 1" | 25.4 |
Fractional bits step up in 64ths of an inch, 1/64" to 1". Decimal and millimetre values are the fixed standard equivalents (mm = inch × 25.4). Need the small number (#1–#80) or letter (A–Z) bits? See the complete number & letter reference.
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How to use it
Read down the column for the system you know — fraction, decimal inch, or millimetre — and across for the equivalents. Metric sizes usually land between two fractional bits, so pick the nearest for a snug fit or the next size up for clearance.
Have an exact size to match? The drill bit size converter gives you the nearest bit in every system, including number and letter sizes.
Common questions
What order do drill bit sizes go in?
This chart runs smallest to largest. Fractional bits step up in 64ths of an inch — 1/64", 1/32", 3/64", and so on up to 1". (Number and letter bits have their own order: number bits actually get smaller as the number gets bigger — see the complete number-and-letter reference.)
How do I read a drill bit size chart from mm to inches?
Find your millimetre value in the mm column and read across to the fractional and decimal-inch equivalents. Most metric sizes fall between two fractional bits — for example 6 mm sits between 15/64" (5.95 mm) and 1/4" (6.35 mm). For an exact match either way, the drill bit size converter does it instantly.
What are the most common drill bit sizes?
For everyday wood and general DIY work, the common fractional bits run from about 1/16" up to 1/2" in 1/16" or 1/32" steps, with 1/8", 3/16", 1/4", 5/16" and 3/8" seeing the most use. This chart lists every fractional size from 1/64" to 1" with its decimal and millimetre equivalent.
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Where these numbers come from
Fractional drill sizes are exact (n/64 of an inch); the decimal and millimetre columns are the standard published equivalents, with millimetres computed as the inch value times 25.4. These are universal, undisputed reference values.
Drill bit decimal and millimetre equivalents are fixed industry-standard values. Bit diameters are nominal; a real bit and the hole it cuts can vary slightly — for precision work, measure the bit.