If you look inside the zippered pouch of any seasoned crocheter, you’ll likely find a chaotic jumble of colorful handles, shimmering aluminum, and perhaps a few heirloom steel hooks passed down from a grandmother. It’s a collection that grows obsessionally over time. But if you were to secretly observe that same crafter actually working—whether they are parked on the sofa on a Tuesday night or waiting in the carpool line—you would notice something interesting. They aren't using the obscure size B hook, nor are they wielding the giant size Q.
Nine times out of ten, they are holding one of two specific tools: the H or the G.
These two sizes are the absolute workhorses of the crochet world. They are the dependable friends you turn to for everything from cozy afghans to structured amigurumi. Yet, for beginners, the distinction between them—and the alphabet soup of US sizing conventions—can be surprisingly murky. Why does one pattern demand an H while a seemingly identical one asks for a G? Does that single millimeter really change the outcome of your project?
The short answer is yes, drastically. Understanding the personality of these two hooks is the difference between a stiff, board-like scarf and one that drapes elegantly around your neck. Let’s break down the mechanics, the metric conversions, and the specific use cases for the two most important tools in your kit.
Why Size H and G are Essential for Beginners
When you first walk into a craft store, the wall of hooks is intimidating. You have tiny steel lace hooks on one side and massive plastic broomsticks on the other. The H and G hooks sit comfortably in the middle of this spectrum, and that positioning is exactly why they are the first tools you should own.
The Worsted Weight Connection
The primary reason these two sizes are non-negotiable for beginners is their relationship with worsted weight yarn. In the US, worsted weight (or size 4 medium) is the most widely available, affordable, and easy-to-handle yarn. It is the standard for learning because it’s thick enough to see your stitches clearly but not so thick that it becomes unwieldy. The H and G hooks are mechanically designed to manage this specific thickness of yarn. If you try to hook worsted yarn with a tiny size D hook, you’ll split the fibers; try it with a size N, and your stitches will be loose and shapeless. The H and G are the "Goldilocks" sizes for the most common yarn in the world.
Building Muscle Memory
There is also a physical aspect to why we start here. Learning to crochet is entirely about muscle memory—teaching your hands how to tension the yarn and rotate the hook simultaneously. Extremely large hooks require exaggerated wrist movements, while tiny hooks require intense, finger-cramping precision. The H and G sizes fit naturally into the average human hand grip, allowing you to focus on the mechanics of the stitch rather than wrestling with the tool itself. If you master your tension on a size H, transitioning to other sizes later becomes intuitive.
Crochet Hook Size H Profile
If I had to choose a single hook to take to a desert island (assuming the island was stocked with yarn), it would be the Size H. It is the universal standard, the baseline from which all other tension is measured.
The Metric Translation
In the world of standardized measurements, the crochet hook size H equates to 5.0mm. This is a nice, round number that makes it easy to remember. However, you might occasionally stumble upon vintage hooks or specific brands where an H is labeled as 5.5mm or slightly different, though 5.0mm is the modern global standard. If you are buying a pattern written in the UK or Australia, they might not use the letter "H" at all; they will simply call for a 5mm hook. Knowing this conversion saves you a headache when you’re trying to translate international patterns.
The H Hook Personality: Drape and Flow
The H hook is famous for creating "drape." Drape refers to how a fabric hangs or moves. When you use a 5.0mm hook with standard worsted yarn, the resulting loops are just loose enough to allow the fabric to be flexible. It breathes. This makes the H hook the undisputed king of wearable items and blankets. If you are making a beanie, a scarf, a cardigan, or a granny square afghan, you want the fabric to mold to the body or the bed. You don't want it to stand up on its own.
Expert Tip on Material Selection
Patricia's Pro-Tip: I've seen many clients make the mistake of buying the cheapest plastic H hook they can find because it's "just for practice." The simple fix is to invest in an aluminum hook or an ergonomic hook with an elastomer handle immediately. The 5.0mm size sees so much friction and movement that plastic tends to create "drag" on the yarn, making your learning curve steeper. Metal slides; plastic drags. For an H hook, you want speed.
The G Hook Profile: Size and Best Uses
If the H hook is about flow and drape, the G hook is about structure and integrity. It is slightly smaller, slightly stricter, and essential for projects where gaps are the enemy.
The Metric Nuance
Here is where things get a little technical and historically interesting. A G crochet hook in mm is typically 4.0mm. However, depending on the brand manufacturer (specifically the old debate between Boye and Bates styles), you might find G hooks labeled as 4.25mm. While a 0.25mm difference seems negligible, in the world of precision crafting, it can slightly alter your gauge. For general purposes, treat the G hook as a 4.0mm tool. If a pattern calls for a 4.0mm and you only have a 4.25mm, you are usually safe, but keep an eye on your tension.
The G Hook Personality: Structure and Stiffness
The G hook creates a fabric that is dense. Because the head of the hook is smaller, it forces the loops of yarn to be smaller and tighter. This reduces the space between stitches. Why would you want this? You want this when you are making things that need to hold a specific shape or contain stuffing. Bags, baskets, placemats, and slippers often benefit from the G hook because the resulting fabric is sturdy. It doesn't flop over; it holds its own weight.
The 7 Hook Confusion
You may occasionally see a "Size 7" hook mentioned in older patterns or different brand sizing charts. A size 7 is usually 4.5mm, sitting awkwardly right between the G (4.0mm) and the H (5.0mm). While the 7 is a perfectly fine hook, the industry has largely standardized around the G and H as the primary steps. If you find yourself needing a tension that is "just a little looser than G" but "tighter than H," the 7 is your bridge, but it is far less common in modern pattern writing.
US Crochet Hook Sizes: Where H and G Fit In
To truly understand your tools, you have to zoom out and look at the full spectrum of US crochet hook sizes. The US system uses an alphabetical scale, starting from B (very small) and going up to Y or Z (extremely large).
The Alphabet Spectrum
Think of the hook sizes as a hill. At the bottom of the hill, on the left, you have sizes B (2.25mm), C (2.75mm), D (3.25mm), and E (3.5mm). These are your "finesse" hooks, used for lightweight yarns, baby clothes, and delicate socks. They require dexterity and good lighting.
At the top of the hill, dominating the center, are F, G, H, I, and J. This is the "sweet spot." Specifically, G (4.0mm) and H (5.0mm) sit right at the summit. They represent the average tension of the average human hand using the average yarn.
On the downward slope to the right, you enter the land of chunky crochet. K (6.5mm), L (8.0mm), M/N (9.0mm), and beyond. These are the "speed" hooks used with thick, bulky yarns to whip up a blanket in a weekend.
Why "Workhorse" is the Right Term
I call G and H the "workhorses" because they are the transitional point. A G hook is small enough to handle some lighter DK (Double Knitting) weight yarns if you want a loose structure, but it can also handle worsted weight for a tight structure. An H hook can handle worsted weight perfectly, but can also manage a slightly bulkier yarn if you want a tight weave. They are the most versatile tools because they straddle the line between fine work and bulk work. If you lose your J hook, you might be annoyed. If you lose your H hook, you stop working until you replace it.
Amigurumi vs. Blankets: Which Hook to Use?
This is the most common question I field from beginners who have just bought a multi-pack of hooks and a ball of yarn. They want to know which stick to grab. The answer depends entirely on what you want the final object to do.
The Blanket Rule: Reach for the H
When you are making a blanket, your primary goal is comfort. You want the blanket to drape over your knees, not stand up stiff as a board. If you use a G hook with worsted yarn for a blanket, the result will be heavy, stiff, and use significantly more yarn because the stitches are so compacted. The H hook (5.0mm) allows air into the stitches. It creates a fabric that is warm but flexible. In my own projects, I sometimes even size up to an I (5.5mm) for blankets just to ensure maximum coziness, but the H is the standard starting point.
The Amigurumi Rule: Reach for the G
Amigurumi—the Japanese art of crocheting small, stuffed creatures—has a completely different set of requirements. Here, "drape" is a disaster. If your fabric is loose, the white polyester stuffing will show through the gaps between your stitches, ruining the aesthetic of your creature. Furthermore, amigurumi needs to hold a 3D shape against the pressure of the stuffing.
This is why the G hook (4.0mm) is the standard for amigurumi using worsted weight yarn. In fact, experienced amigurumi makers often suggest "sizing down" from what the yarn label recommends. If a yarn label says "Use an H hook," an amigurumi artist will instinctively grab a G or even an F. The goal is to create a fabric so tight that it looks like a solid textile rather than a collection of loops.
A Quick Test: The Swatch
If you are ever in doubt, take ten minutes to do a test. Crochet a small square (10 stitches by 10 rows) with the G hook, and another with the H hook using the same yarn. Feel them. Squeeze them. The G square will feel harder and smaller. The H square will feel softer and flop over your finger. That tactile difference tells you everything you need to know about which hook fits your project.
Frequently Asked Questions About Workhorse Hooks
What if my pattern calls for an H hook but I only have a G?
You can use the G hook, but your finished item will be smaller and the fabric will be stiffer. If fit is important (like a hat or sweater), this is risky because the garment might be too tight. To compensate, you would need to crochet with a very loose tension, which is difficult to maintain consistently.
Is a 5.0mm hook always an H?
Generally, yes. In the US system, H is synonymous with 5.0mm. However, manufacturing tolerances vary slightly. Always check the millimeter size stamped on the hook or the package, as that is the universal measurement regardless of the arbitrary letter assigned to it.
Why do my stitches look tighter with an H hook than my friend's stitches?
This is likely due to your personal "gauge" or tension. Some people are tight crocheters (stress grip!) and others are loose crocheters. If you naturally crochet tightly, your H hook work might look like someone else's G hook work. This is normal, which is why checking your gauge against the pattern is vital for wearable items.
Can I use a G hook for chunky yarn?
It is not recommended. A G hook has a small throat (the part that catches the yarn). Chunky yarn is too thick to fit comfortably into that throat, leading to the yarn splitting and the hook snagging. It is physically frustrating and will result in a fabric that is incredibly stiff and board-like.
The difference between a 4.0mm G hook and a 5.0mm H hook is only one millimeter, but that millimeter represents the divide between structure and flow. As you continue your crochet journey, you will likely find yourself buying multiples of these sizes—one for the travel bag, one for the living room, and one spare "just in case." They are the foundation of the craft. Whether you are sculpting a tiny dinosaur with a G hook or draping a cozy afghan with an H, mastering these two tools is the first step toward confident, professional-looking crochet.
