Crochet hooks come in different needle sizes. But that’s not all, because there are also different systems for designating the needle sizes for crochet hooks. So it can happen that your crochet hook or crochet pattern comes from another country and you don’t understand a word when it comes to the needle size designation.
To prevent this from happening to you again, here is a translation of the various needle sizes into the different systems. This way, you can use any crochet hook and read any crochet pattern, even if there is a “strange” designation for the needle size.
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Size Chart: Crochet Hooks in Different Needle Sizes
| Metric | British | Alphabetical | Numerical | Bamboo | Strength |
| Germany | Canada, England | USA | USA | Japan | – |
| – | – | 10 steel | – | 1.0 mm | |
| 1.25 mm | 16 | 8 steel | 000 | – | 1.25 mm |
| 1.5 mm | 15 | 7 steel | 00 | – | 1.5 mm |
| 1.75 mm | 14 | 5 steel | – | – | 1.75 mm |
| 2 mm | – | – | 0 | – | 2.0 mm |
| – | – | – | – | 0 | 2.1 mm |
| 2.25 mm | 13 | B | 1 | – | 2.25 mm |
| – | – | – | – | 1 | 2.4 mm |
| 2.5 mm | 12 | – | 1 1/2 | – | 2.5 mm |
| – | – | – | – | 2 | 2.7 mm |
| 2.75 mm | – | C | 2 | – | 2.75 mm |
| 3 mm | 11 | – | 2 1/2 | 3 | 3.0 mm |
| – | 10 | D | 3 | – | 3.25 mm |
| – | – | – | – | 4 | 3.3 mm |
| 3.5 mm | – | E | 4 | – | 3.5 mm |
| – | – | – | – | 5 | 3.6 mm |
| – | 9 | F | 5 | – | 3.75 mm |
| – | – | – | – | 6 | 3.9 mm |
| 4 mm | 8 | G | – | – | 4.0 mm |
| – | – | – | – | 7 | 4.2 mm |
| – | – | – | 6 | – | 4.25 mm |
| 4.5 mm | 7 | – | 7 | 8 | 4.5 mm |
| – | – | – | – | 9 | 4.8 mm |
| 5 mm | 6 | H | 8 | – | 5.0 mm |
| – | – | – | – | 10 | 5.1 mm |
| – | – | – | – | 11 | 5.4 mm |
| 5.5 mm | 5 | I | 9 | – | 5.5 mm |
| – | – | – | – | 12 | 5.7 mm |
| 6 mm | 4 | J | 10 | 13 | 6.0 mm |
| – | – | – | – | 14 | 6.3 mm |
| 6.5 mm | 3 | K | 10 1/2 | – | 6.5 mm |
| – | – | – | – | 15 | 6.6 mm |
| 7 mm | 2 | – | – | 7 mm | 7.0 mm |
| – | 1 | – | – | – | 7.5 mm |
| 8 mm | 0 | L | 11 | 8 mm | 8.0 mm |
| 9 mm | 00 | M | 13 | 9 mm | 9.0 mm |
| 10 mm | 000 | N | 15 | 10 mm | 10.0 mm |
| 15 mm | – | P, Q | – | – | 15.0 mm |
Explanations of Regional Measurement Systems for Crochet Hooks
These different measurement systems can be confusing when using international crochet patterns or when buying crochet hooks from different regions. It is helpful to know the conversions between the systems to select the right needle size for the respective project. This ensures that regardless of the origin of the pattern or needle, the desired results can be achieved.
Metric
The metric measurement system is internationally widespread and is based on the decimal system. It is used in most countries around the world, including German-speaking countries. In this system, the needle size is measured in millimeters. A crochet hook with a size of 2.0 mm therefore has a diameter of 2 millimeters. This system is particularly precise and allows for targeted searches for specific sizes.
British
The British measurement system is mainly used in the UK and some of its former colonies. Unlike the metric system, here the needle sizes are expressed in numbers and letters. For example, the designation “6” stands for a needle size of 6 mm. This assignment may initially seem confusing, but it is easy to understand for those familiar with this system.
Alphabetical
The alphabetical measurement system is closely related to the British system and is used in the USA. Letters are used to indicate the needle size. An example of this is the designation “G”, which corresponds to a needle size of 4.0 mm. It is important to note that these assignments are not always intuitive, especially for people familiar with other measurement systems.
Numerical
The numerical measurement system, also used in the USA, uses numbers to describe the needle size. A needle labeled “7” has a diameter of 4.5 mm. This system is comparatively uncomplicated and easy to understand, provided you know the corresponding conversions.
Bamboo
The bamboo measurement system, used in Japan, is specific to this country. It uses its own designation that cannot be directly compared to other measurement systems. For example, the Japanese designation “2.7 mm” corresponds to a specific needle size. This can initially be a challenge, but over time, you will become familiar with the specific information.
What to Do When Needle Size Conversion is Missing?
It may happen that you cannot find an exact equivalent in the other measurement system when converting needle size. In such cases, it is advisable to choose a similar needle size and create a gauge swatch. This involves crocheting a small sample to ensure that the stitch size matches the pattern. If the stitches are too tight, switch to a larger hook, while if the stitches are too loose, a smaller hook may be the solution. While this approach may require some experimentation, it ultimately allows for successful execution of the crochet pattern.
What to Do When Needle Size Information is Missing?
It happens that crochet hooks do not have a clear marking of their size. In such cases, it is helpful to use a needle size gauge template. These templates have various holes, each corresponding to a specific needle size. By inserting the needle through the appropriate hole, you can determine the size. Alternatively, you can also use a caliper or a gauge to measure the diameter of the needle. If none of these tools are available, you can crochet a sample for comparison. Different needle sizes are tried until the desired stitch size is achieved. While this may take a bit more time, it ultimately allows for precise work and successful results.
