To quickly answer the question, you came here asking: the size H crochet hook is 5.0 mm.
However let’s delve into why selecting the correct crochet hook size matters when you are completing a crochet project! This information is important, especial
Are you feeling overwhelmed by all the different sizes and types of hooks out there? Trying to figure out which hook size to use for a particular yarn weight or crochet pattern can be a challenge.
In this blog post, we’ll shine some light on how many mm a size h crochet hook is, along with other useful information about yarn weights, larger hooks, steel hooks, and the standard crochet hook sizes. Read on to learn about the different ways that selecting the perfect mm hook can impact for your next crochet projects!
- How many mm a size h crochet hook is
- Yarn weights
- Larger hooks
- Steel hooks
- Standard crochet hook sizes
Introduction to Crochet Hooks
Crochet hooks come in a variety of shapes, sizes, and different materials to suit your individual crafting needs. The different sizes of crochet hooks will impact your final result, so it is important to make sure you use the right hook size.
Standard crochet hooks are usually made of plastic, aluminum, and steel. Steel crochet hooks are often used on finer threads, while aluminum hooks work well with medium and heavier yarns. Different sized hooks can also accommodate a variety of yarn weights.
To select the right size crochet hook for your project, look at the yarn label or pattern instructions and consider the type of yarn you are using. (Usually patterns also list them the recommended hook size, so do make sure you watch out for that especially if you are a beginner crocheter.) Typically, a larger hook is recommended for heavier or thicker weight yarns, while finer or lighter weight yarns require smaller hooks. Crochet hook sizes range from 2 mm to 25 mm (sometimes larger). The standard sizes for regular crochet hooks range from B (2 mm) to N/P/Q (15 mm).
If you find yourself needing a size beyond what is available in standard sizing options, many specialty shops offer extended ranges from 0 mm all the way up to 35 mm as well as longer lengths up to 6 inches overall.
When choosing a crochet hook size remember that each brand may vary slightly in terms of length or manufacturing so make sure you always double-check your measurements before selecting the right hook for your project!

What is a Size H Crochet Hook?
Size H crochet hooks, also known as 5.00 mm hooks, are one of the most common sizes of crochet hook used for many yarn weights. This means that it is used for size medium weight yarns, which are sometimes written on the yarn label as a 4 or 4 Ply.
Size H steel and aluminum hooks are typically 7 inches long and ergonomically designed in order to reduce hand fatigue when crocheting. When looking for a larger hook size to create larger stitches, such as with a bulky or super bulky weight yarn, most commonly used size is I or 5.5 mm crochet hook. However, other larger standard crochet hooks come in sizes J (6mm), K (6.5mm), and L (8mm).
Using specific sizes of crochet needle can help you achieve the finished project you desire; there’s less guess work involved if you follow the indicated patterns and measurements given in your pattern booklet or online video tutorial. Very often these patterns will be written with symbol diagrams that indicate what size hook to use based on what type of project you are making with certain types of yarns. If ever in doubt about what size needle to use for a specific type of project always refer back to the recommended hook usage specified on your pattern instructions or in any related tutorials available online.
Understanding Yarn Weight and Yarn Labels
The weight of yarn is an important factor in determining the best crochet hook size for your project. Knowing your yarn weight, a measurement that indicates the thickness of the yarn, is a great first step in determining the size crochet hook you should use. Most manufacturers of yarn attach a label to their product indicating the details of its weight, which can help you determine if it’s light, medium, bulky and super bulky. Some labels also include information on a recommended size crochet hook to use with that specific yarn weight.
When considering which hook is right for you and your project, most will be classified as either standard or steel hooks. Standard hooks are usually designated with lettering (A through Q) or number (1 to 15). These correspond to MM sizes – 0mm (2/0) to 16mm (Q/15). Steel hooks are slightly thinner and are generally used for thread projects and finer laces. The sizes range from 00000 to 14 and this translates into 1.3mm (00000) up to 12mm (14).
Finding the correct mm with a standard hook is fairly simple as this chart shows:
- A = 2/0 = 0mm
- B = 3/0 = 3mm
- C = 4/0 = 3.5mm
- D = 5/0 = 4mm
- E-F = 6/0 5MM
- G-H= 8/7 7MM
- I-J= 9 7MM
- K-Q= 10-16 #Q 16MM
If your project requires a larger hook than what is listed on the label of your particular yarn, you can choose one that is larger by two or more sizes above what is suggested on the label. For example if a pattern recommends an I or J sized hook but you find it too small, switching to an N would make sense as the increase from 9 mm up to 10 mm should give you better results without sacrificing gauge or creating problems such as too loosely woven stitches or incorrect sizing in garments knit with this type of yarn.

Standard Crochet Hooks and Steel Hooks
When you are learning to crochet, understanding the different crochet hooks and their sizes is an important first step. Standard crochet hooks come in a variety of sizes that refer to their shaft diameter, generally in millimeters (mm). The larger the number, the larger the hook.
Steel hooks are much thinner than regular crochet hooks and range in size from 00 (the smallest) to 14 (the largest). The size range for steel hooks is different than those of standard crochet hooks; the smaller numbers indicate a larger hook size.
To determine the exact mm of a size “h” crochet hook, you will need to look at your yarn label or check your regular and steel crochet hook packaging. Size H is often referred to as an “8 mm” standard crochet hook, however this measurement can vary with different brands. Steel Hook size H indicates a 5 mm diameter metric. In general, it is important to use a hook that complements the weight of yarn specified in your pattern instructions – for example, if the pattern requires worsted weight yarn then you would typically use an 8 mm or 9 mm standard crochet needle or 5-6mm steel hook from sizes 00-1 recommended for worsted weight yarn by many yarn manufacturers.
What is the mm Size of a Size H Crochet Hook?
The mm size of a crochet hook is determined by the yarn label found in the skein or ball of yarn. The label will indicate the weight of the yarn, followed by what size crochet hook is recommended for this yarn weight. A size H crochet hook is 5 mm and is ideal for use with worsted or medium weight yarns (labeled as 4 weight). It is the most commonly used size of standard steel crochet hooks and makes it possible to create larger fabrics than those made with smaller regular crochet hooks.
Steel hooks come in various sizes, usually ranging from 0.6mm – 6mm (the numbers are also indicated on the labels), but Size H (5mm) is a good starting point for most crochet patterns as it falls in the middle range of standard steel hooks. When working with larger yarns, choose one or two sizes larger than the standard Size H to create a looser stitch, while when working with finer threads look for a size that is one or two sizes smaller than Size H. Keep in mind that each pattern differs slightly and may require you to use a slightly different hook size than usual to achieve an optimal result.

Crochet Needles vs. Regular Crochet Hooks
The terms crochet needles and regular crochet hooks are sometimes used interchangeably; however, they refer to two distinct tools that have different applications. Crochet needles typically have a larger hook, while standard crochet hooks generally have a smaller and more uniform size. Additionally, regular crochet hooks are typically made of steel or plastic, while crochet needles may be made of bone, bamboo, aluminum or other materials.
Yarn weight is important when determining the size of a specific standard crochet hook or needle to use for a particular craft project. The yarn label will usually specify the best sized tool for any given yarn and the size is usually in millimeters (mm). This range typically varies from 2–6 mm for steel hooks, 2–12 mm for larger hook sizes and 1–9 mm for regular crochet hooks. Depending on the type of project being worked on (such as doilies, laces or thick winter blankets) it may require using a much larger hook that is not a part of the standard sizes available in most general stores.
Using a Larger Hook for a Crochet Pattern
When you’re working on a crochet pattern, it is important to know what size hook to use to best create the desired effect. Every yarn label includes information on the weight of the yarn and the hook size recommended for that particular yarn.
Steel hooks can be confusing as sizes range from 0 (2 mm) all the way up to 16 (1.5 mm). Standard crochet hooks not considered steel range in size A-P, formerly known as 7-19 but now falling within 4.5 mm – 25 mm.
If you have a pattern that requires using a larger hook than what is typically used for that specific kind of yarn, it is important to refer to the pattern instructions as well as your gauge swatch for more guidance on where to start with your chosen size crochet needle.
Before We Close…
Finally, when selecting the best crochet hook size for your next project, it is important to consider yarn weight and project size. Yarn labels will provide information about the appropriate hook size, although this can be a guide rather than an absolute.
Steel hooks are recommended for small projects with fine yarns, while regular-sized crochet hooks are recommended for larger projects and thicker yarns. Knowing how many mm is equivalent to a size H hook can help you determine the best hook for your project and ensure the end product has a professional finish.
Happy crocheting!
Frequently Asked Questions
How many mm is a size h crochet hook?
The size h crochet hook measures 5.0 mm.
What yarn weight should I use with a size h crochet hook?
The size h crochet hook is typically used with worsted weight yarn.
What is the difference between a size h crochet hook and a larger hook?
A size h crochet hook is 5.0 mm and a larger hook may be 5.5 mm or 6.0 mm.