What is a Drill Bit?
Before discussing about drill bit size chart let us first understand what do you mean by a drill bit? A drill bit is a tool used for creating holes, characterized by its rotational cutting action. When you drill, the pointed end of the bit comes into contact with the material. The other end is known as the shank which remains secured by the jaws of a drill chuck.
Hardware stores stock numerous varieties and designs of drill bits, to the point where they occupy an entire aisle. However, for the scope of our discussion, we will concentrate on the types that are commonly utilized in do-it-yourself (DIY) projects.
What Are Drill Bits Used For?
The main purpose of drill bits is to produce round openings in various materials ranging from drywall and wood to metal and masonry. These holes can serve different purposes such as accommodating anchors or fasteners, or providing pathways for wiring. It is very important to consider the physical form and composition you intend to drill into. Drill bits are available for individual purchase or in sets that contain multiple sizes, often referred to as drill indexes.
What is Drill Bit Size Chart?
It is a tool that helps users in selecting the appropriate bit for their drilling needs. It indicates the diameter, length, and other specifications of the various drill bit sizes available. A drill bit size chart provides information about the sizes and dimensions of different drill bits.
They are generally available in two options which are as follows:
- ANSI Twist Drill Size
- ISO Twist Drill Size
What is ANSI Standard for Drill Bit Size Chart?
The ANSI standard for drill bit sizes is defined in document B94.11M. This standard, known as the “Twist Drill and Drill Bit Size Chart,” sets the guidelines and specifications for different drill bit sizes. By following this standard, manufacturers, professionals, and users can easily select and use drill bits that meet the required specifications and ensure compatibility. It ensures a consistent and universally accepted system for identifying drill bit sizes.
What is ISO Standard for Drill Bit Size Chart?
The ISO standard for drill bit sizes is outlined in the document ISO 235. This standard, titled “Drill and Countersink Bits – Nominal Sizes and Dimensions,” provides guidelines and specifications for the sizes and dimensions of drill bits. It aims to establish a consistent and internationally recognized system for identifying drill bit sizes. The ISO 235 standard ensures compatibility and uniformity in the manufacturing, selection, and use of drill bits across different countries and industries.
Read More: NPT Size Chart
Different Drill Bit Sizes
Drill bits come in a variety of sizes to accommodate different drilling needs. Here are some common drill bit sizes:
| Small | 1/16 inch |
| Medium | 1/8 inch |
| Intermediate | 3/16 inch |
| Standard | 1/4 inch |
| Large | 5/16 inch |
| Extra Large | 3/8 inch |
| Half-inch | 1/2 inch |
| Five eighth-inch | 5/8 inch |
| Three-quarter-inch | 3/4 inch |
| One-inch | 1 inch |
Remember, these sizes are just a sample of the various drill bit sizes available. Drill bits can have smaller or larger increments, depending on the specific drilling needs.
Drill Bit Size Chart
The ANSI/ASME B94.11M-1993 standard encompasses the commonly used drill bits found in industries, ensuring their widespread availability. Fractional sizes are measured in inches, while metric sizes are measured in millimeters. The drill size chart provides information on twist drill specifications for diameters up to 1.0 inches.
↠ANSI Drill Bit Size Chart
| Drill (in.) | Decimal | Drill (in.) | Decimal | Drill (in.) | Decimal |
| 80 | 0.013 | 1/8 | 0.125 | O | 0.316 |
| 79 | 0.014 | 30 | 0.128 | P | 0.323 |
| 1/64 | 0.015 | 29 | 0.136 | 21/64 | 0.328 |
| 78 | 0.016 | 28 | 0.140 | Q | 0.332 |
| 77 | 0.018 | 9/64 | 0.141 | R | 0.339 |
| 76 | 0.020 | 27 | 0.144 | 11/32 | 0.343 |
| 75 | 0.021 | 26 | 0.147 | S | 0.348 |
| 74 | 0.022 | 25 | 0.149 | T | 0.358 |
| 73 | 0.024 | 24 | 0.152 | 23/64 | 0.359 |
| 72 | 0.025 | 23 | 0.154 | U | 0.368 |
| 71 | 0.026 | 5/32 | 0.156 | 3/8 | 0.375 |
| 70 | 0.028 | 22 | 0.157 | V | 0.377 |
| 69 | 0.029 | 21 | 0.159 | W | 0.386 |
| 68 | 0.031 | 20 | 0.161 | 25/64 | 0.390 |
| 1/32 | 0.031 | 19 | 0.166 | X | 0.397 |
| 67 | 0.032 | 18 | 0.169 | Y | 0.404 |
| 66 | 0.033 | 11/64 | 0.171 | 13/32 | 0.406 |
| 65 | 0.035 | 17 | 0.173 | Z | 0.413 |
| 64 | 0.036 | 16 | 0.177 | 27/64 | 0.421 |
| 63 | 0.037 | 15 | 0.180 | 7/16 | 0.437 |
| 62 | 0.038 | 14 | 0.182 | 29/64 | 0.453 |
| 61 | 0.039 | 13 | 0.185 | 15/32 | 0.468 |
| 60 | 0.040 | 3/16 | 0.187 | 31/64 | 0.484 |
| 59 | 0.041 | 12 | 0.189 | 1/2 | 0.500 |
| 58 | 0.042 | 11 | 0.191 | 33/64 | 0.515 |
| 57 | 0.043 | 10 | 0.193 | 17/32 | 0.531 |
| 56 | 0.046 | 9 | 0.196 | 35/64 | 0.546 |
| 3/64 | 0.047 | 8 | 0.199 | 9/16 | 0.562 |
| 55 | 0.052 | 7 | 0.201 | 37/64 | 0.578 |
| 54 | 0.055 | 13/64 | 0.203 | 19/32 | 0.593 |
| 53 | 0.059 | 6 | 0.204 | 39/64 | 0.609 |
| 1/16 | 0.062 | 5 | 0.205 | 5/8 | 0.625 |
| 52 | 0.063 | 4 | 0.209 | 41/64 | 0.640 |
| 51 | 0.067 | 3 | 0.213 | 21/32 | 0.656 |
| 50 | 0.070 | 7/32 | 0.218 | 43/64 | 0.671 |
| 49 | 0.073 | 2 | 0.221 | 11/16 | 0.687 |
| 48 | 0.076 | 1 | 0.228 | 45/64 | 0.703 |
| 5/64 | 0.078 | A | 0.234 | 23/32 | 0.718 |
| 47 | 0.079 | 15/64 | 0.234 | 47/64 | 0.734 |
| 46 | 0.081 | B | 0.238 | 3/4 | 0.750 |
| 45 | 0.082 | C | 0.242 | 49/64 | 0.765 |
| 44 | 0.086 | D | 0.246 | 25/32 | 0.781 |
| 43 | 0.089 | E | 0.250 | 51/64 | 0.796 |
| 42 | 0.093 | 1/4 | 0.250 | 13/16 | 0.812 |
| 3/32 | 0.094 | F | 0.257 | 53/64 | 0.828 |
| 41 | 0.096 | G | 0.261 | 27/32 | 0.843 |
| 40 | 0.098 | 17/64 | 0.265 | 55/64 | 0.859 |
| 39 | 0.099 | H | 0.266 | 7/8 | 0.875 |
| 38 | 0.101 | I | 0.272 | 57/64 | 0.890 |
| 37 | 0.104 | J | 0.277 | 29/32 | 0.906 |
| 36 | 0.106 | K | 0.281 | 59/64 | 0.921 |
| 7/64 | 0.109 | 9/32 | 0.281 | 15/16 | 0.937 |
| 35 | 0.110 | L | 0.290 | 61/64 | 0.953 |
| 34 | 0.111 | M | 0.295 | 31/32 | 0.968 |
| 33 | 0.113 | 19/64 | 0.296 | 63/64 | 0.984 |
| 32 | 0.116 | N | 0.302 | 1 | 1.000 |
| 31 | 0.120 | 5/16 | 0.312 |
↠ISO (Metric) Drill Bit Size Chart
| Drill (mm) | Decimal (in.) | Drill (mm) | Decimal (in.) | Drill (mm) | Decimal (in.) |
| 0.35 | 0.013 | 3.4 | 0.133 | 8.0 | 0.315 |
| 0.4 | 0.015 | 3.5 | 0.137 | 8.1 | 0.318 |
| 0.45 | 0.017 | 3.6 | 0.141 | 8.2 | 0.322 |
| 0.5 | 0.019 | 3.7 | 0.145 | 8.25 | 0.324 |
| 0.55 | 0.021 | 3.75 | 0.147 | 8.3 | 0.326 |
| 0.6 | 0.023 | 3.8 | 0.149 | 8.4 | 0.330 |
| 0.65 | 0.025 | 3.9 | 0.153 | 8.5 | 0.334 |
| 0.7 | 0.027 | 4.0 | 0.157 | 8.6 | 0.338 |
| 0.75 | 0.029 | 4.1 | 0.161 | 8.7 | 0.342 |
| 0.8 | 0.031 | 4.2 | 0.165 | 8.75 | 0.344 |
| 0.85 | 0.033 | 4.25 | 0.167 | 8.8 | 0.346 |
| 0.9 | 0.035 | 4.3 | 0.169 | 8.9 | 0.350 |
| 0.95 | 0.037 | 4.4 | 0.173 | 9.0 | 0.354 |
| 1.0 | 0.039 | 4.5 | 0.177 | 9.1 | 0.358 |
| 1.05 | 0.041 | 4.6 | 0.181 | 9.2 | 0.362 |
| 1.1 | 0.043 | 4.7 | 0.185 | 9.25 | 0.364 |
| 1.15 | 0.045 | 4.75 | 0.187 | 9.35 | 0.366 |
| 1.2 | 0.047 | 4.8 | 0.189 | 9.4 | 0.370 |
| 1.25 | 0.049 | 4.9 | 0.192 | 9.5 | 0.374 |
| 1.3 | 0.051 | 5.0 | 0.196 | 9.6 | 0.378 |
| 1.35 | 0.053 | 5.1 | 0.200 | 9.7 | 0.3819 |
| 1.4 | 0.055 | 5.2 | 0.204 | 9.75 | 0.383 |
| 1.45 | 0.057 | 5.25 | 0.206 | 9.8 | 0.385 |
| 1.5 | 0.059 | 5.3 | 0.208 | 9.9 | 0.389 |
| 1.55 | 0.061 | 5.4 | 0.212 | 10.0 | 0.393 |
| 1.6 | 0.062 | 5.5 | 0.216 | 10.5 | 0.413 |
| 1.65 | 0.064 | 5.6 | 0.220 | 11.0 | 0.433 |
| 1.7 | 0.066 | 5.7 | 0.224 | 11.5 | 0.452 |
| 1.75 | 0.068 | 5.75 | 0.226 | 12 | 0.472 |
| 1.8 | 0.070 | 5.8 | 0.228 | 12.5 | 0.492 |
| 1.85 | 0.072 | 5.9 | 0.232 | 13.0 | 0.511 |
| 1.9 | 0.074 | 6.0 | 0.236 | 13.5 | 0.531 |
| 1.95 | 0.076 | 6.1 | 0.240 | 14.0 | 0.551 |
| 2.0 | 0.078 | 6.2 | 0.244 | 14.5 | 0.570 |
| 2.05 | 0.080 | 6.25 | 0.246 | 15.0 | 0.590 |
| 2.1 | 0.082 | 6.3 | 0.248 | 15.5 | 0.610 |
| 2.15 | 0.084 | 6.4 | 0.252 | 16.0 | 0.630 |
| 2.2 | 0.086 | 6.5 | 0.255 | 16.5 | 0.649 |
| 2.25 | 0.088 | 6.6 | 0.259 | 17.0 | 0.669 |
| 2.3 | 0.090 | 6.7 | 0.263 | 17.5 | 0.688 |
| 2.35 | 0.092 | 6.75 | 0.265 | 18.0 | 0.708 |
| 2.4 | 0.094 | 6.8 | 0.267 | 18.5 | 0.728 |
| 2.45 | 0.096 | 6.9 | 0.271 | 19.0 | 0.748 |
| 2.5 | 0.098 | 7.0 | 0.275 | 19.5 | 0.767 |
| 2.55 | 0.100 | 7.1 | 0.279 | 20.0 | 0.787 |
| 2.6 | 0.102 | 7.2 | 0.283 | 20.5 | 0.807 |
| 2.65 | 0.104 | 7.25 | 0.285 | 21.0 | 0.826 |
| 2.7 | 0.106 | 7.3 | 0.287 | 21.5 | 0.846 |
| 2.75 | 0.108 | 7.4 | 0.291 | 22.0 | 0.866 |
| 2.8 | 0.110 | 7.5 | 0.295 | 22.5 | 0.885 |
| 2.9 | 0.114 | 7.6 | 0.299 | 23.0 | 0.905 |
| 3.0 | 0.118 | 7.7 | 0.303 | 23.5 | 0.925 |
| 3.1 | 0.122 | 7.75 | 0.305 | 24.0 | 0.944 |
| 3.2 | 0.126 | 7.8 | 0.307 | 24.5 | 0.964 |
| 3.25 | 0.128 | 7.9 | 0.311 | 25.0 | 0.984 |
| 3.3 | 0.129 |
FAQ’s
What size drill bit do you need for a 3/8 anchor chart?
What size drill bit is 60 thousands size chart?
How to read a drill size chart?
1. Check the Units: Make sure you know whether the chart uses inches or millimeters.
2. Find the Sizes: Look for the list of drill sizes, usually organized in order.
3. Locate Your Size: Find the specific drill size you need, listed as a fraction, decimal, or number.
4. Get the Bit Size: Look for the recommended drill bit size column that corresponds to your chosen measurement. It may suggest a standard size too.
5. Consider the Material: Remember that different materials may require different drill bit sizes. Some charts offer separate recommendations for various materials.
By following these steps, you can easily read and understand a drill size chart to select the right drill bit size for your task.
What are metric drill bits?
Video on how to select the right Drill Bit?
Conclusion
In conclusion, familiarizing yourself with the drill bit size chart is essential for anyone involved in drilling tasks. It enables you to select the right drill bit size, ensuring precise and accurate holes. The chart provides a clear and concise reference, allowing you to choose the appropriate drill bit size based on the desired hole diameter, making your drilling projects more successful.
