Disclosure: This page contains affiliate links to Amazon (tag: ytearnings-20). We may earn a small commission at no extra cost to you if you purchase through these links.
Crochet Hook Size Chart — Complete US and Metric Guide
Last updated: March 27, 2026
Pin this chart for quick reference at your craft table: a color-coded table showing every standard US crochet hook letter, its metric millimeter equivalent, and the yarn weight it pairs with — from a fine B/1 (2.25 mm) for lace all the way up to a Q hook (15 mm+) for jumbo arm-knitting yarn. Scroll down for the full printable-friendly table.
Crochet hooks in the US use a letter-and-number system (B/1 through Q) alongside metric millimeter sizes. The most common beginner hook is a G/6 (4.0 mm) paired with worsted weight yarn. This guide covers the full US-to-metric conversion chart, steel hooks for thread work, and which hook size to use for each yarn weight category.
US Letter Size to Metric Conversion Chart
Most patterns published in the United States use the letter-and-number system alongside metric sizes. International patterns almost always use millimeters. The chart below covers every standard size. Note that the letter system is not perfectly standardized across manufacturers — a J hook from one brand may be 5.50 mm while another brand's J is 6.00 mm. Always verify by millimeter size.
| US Size | Metric (mm) | Best For |
|---|---|---|
| B/1 | 2.25 mm | Fingering weight (CYC 1) |
| C/2 | 2.75 mm | Fingering to sport weight |
| D/3 | 3.25 mm | Sport to DK weight |
| E/4 | 3.50 mm | DK weight |
| F/5 | 3.75 mm | DK to worsted weight |
| G/6 | 4.00 mm | Worsted weight (CYC 4) — most common beginner size |
| H/8 | 5.00 mm | Worsted to bulky weight |
| I/9 | 5.50 mm | Bulky weight (CYC 5) |
| J/10 | 6.00 mm | Bulky weight |
| K/10.5 | 6.50 mm | Bulky weight |
| L/11 | 8.00 mm | Super bulky (CYC 6) |
| M/13 | 9.00 mm | Super bulky |
| N/15 | 10.00 mm | Super bulky to jumbo |
| P/16 | 11.50 mm | Jumbo weight (CYC 7) |
| Q | 15.00 mm+ | Jumbo and arm-knitting yarn |
If you are working from a vintage pattern or a pattern with no size listed, a needle and hook size gauge card lets you identify any hook by inserting the shaft into labeled holes until you find a snug fit. Our free Needle Guide tool also converts between US, metric, and UK sizes in one place.
Hook Size by Yarn Weight
The Craft Yarn Council (CYC) standard recommends the following hook size ranges as starting points. Your personal tension determines whether you need to go up or down from these suggestions — which is why swatching matters.
| CYC Weight | Category Name | Recommended Hook Range |
|---|---|---|
| CYC 0 | Lace | B/1 to E/4 (2.25–3.5 mm) or steel hooks 4–7 |
| CYC 1 | Fingering / Super Fine | B/1 to E/4 (2.25–3.5 mm) |
| CYC 2 | Sport / Fine | E/4 to 7 (3.5–4.5 mm) |
| CYC 3 | DK / Light | G/6 to I/9 (4.0–5.5 mm) |
| CYC 4 | Worsted / Medium | G/6 to K/10.5 (4.0–6.5 mm) |
| CYC 5 | Bulky | K/10.5 to M/13 (6.5–9.0 mm) |
| CYC 6 | Super Bulky | M/13 to Q (9.0–15.0 mm) |
| CYC 7 | Jumbo | Q and larger (15.0 mm+) |
Use the Yarn Weight Chart on FiberTools to identify any unlabeled yarn by wraps-per-inch or gauge swatch before selecting a hook. This matters especially when substituting yarn — the same CYC category from different brands can have noticeably different thicknesses.
Steel Hooks for Thread Crochet
Steel hooks are a separate system for crochet thread (size 10 cotton, lace yarn, bedspread weight). They are smaller and harder than aluminum hooks to handle fine thread tension. Unlike regular hooks, steel sizes run backward — a higher number means a smaller hook.
Common steel hook sizes and their uses: Steel 14 (0.75 mm) is the finest available, for delicate lacework. Steel 10 (1.15 mm) and Steel 8 (1.50 mm) are used for lightweight doilies. Steel 6 (1.80 mm) is a standard starting point for size 10 thread and filet crochet curtains. Steel 0 (3.25 mm) bridges the gap between thread and regular yarn. For classic filet crochet, a Steel 6 or 7 with size 10 thread is the most common combination.
Inline vs Tapered Hooks
Beyond size, hook design affects how you crochet. The two main styles are inline (Boye style) and tapered (Susan Bates style).
Inline hooks have the throat cut in line with the shaft — the hook and shaft are the same diameter. The yarn sits in a defined groove, which helps tight crocheters maintain consistent stitch size. Tapered hooks have a throat that curves outward from a slightly larger hook head to a narrower shaft. Stitches slide off more easily, which some crocheters find faster. Neither is objectively better. Try both with the same yarn and pattern — your preference depends on your tension and grip style.
Ergonomic Handles: Worth the Investment
Standard aluminum hooks are thin cylinders — effective but hard on the hands during long sessions. Ergonomic handles are thicker, cushioned, and often contoured to reduce grip tension. Boye and Susan Bates both make ergonomic lines. Ergonomic hook sets on Amazon (affiliate link) range from $15–$40 for a full set and include sizes B through K.
If you crochet more than an hour at a time, ergonomic handles reduce hand fatigue significantly. The difference becomes more apparent with finer yarn and tighter tension. You can also purchase separate ergonomic grip sleeves that slide over standard hooks if you already have a set you love.
How to Identify an Unlabeled Hook
Hook markings wear off. Secondhand sets, inherited collections, and unlabeled craft store hooks are common. Two reliable methods:
A needle gauge card has labeled holes — insert the hook shaft (not the throat) until you find the snug fit. A digital caliper measures the shaft diameter in millimeters and costs under $10. Both tools work for knitting needles too. The FiberTools Needle Guide provides the full size reference without any tools at all.
Hook Recommendations by Project Type
Different project types benefit from specific hook choices beyond just matching yarn weight. For amigurumi in worsted weight, use a G/6 (4.0 mm) — one to two sizes smaller than the yarn label recommends — to create a dense fabric that hides stuffing.
For granny squares and blankets in worsted, a standard H/8 (5.0 mm) or I/9 (5.5 mm) produces a fabric with good drape. For shawls and wraps in DK or lace weight, go one size up from the yarn label to create an open, drapey fabric. Use our Gauge Calculator to confirm your stitch count matches the pattern requirements before committing to a full project.
Frequently Asked Questions
What size crochet hook is best for beginners?
A G/6 (4.0 mm) or H/8 (5.0 mm) hook paired with worsted weight (CYC 4) yarn is the best starting combination. The medium size is comfortable to hold, stitches are easy to see and count, and worsted yarn is widely available and inexpensive. Avoid very fine or very bulky yarn until you are comfortable with basic stitches.
What is the difference between US and metric crochet hook sizes?
US sizes use a letter-and-number system (B/1 through Q). Metric sizes are measured in millimeters and are universally standardized. The US letter system is not consistent across all manufacturers — always check the millimeter size when purchasing hooks or following international patterns.
What hook size do I use for amigurumi?
For worsted weight amigurumi, use a G/6 (4.0 mm) — smaller than the yarn label recommends. The tighter fabric prevents stuffing from showing through gaps. Check your pattern's gauge note; some patterns specify 12–14 sc per 4 inches, which gives you a precise target.
What are steel crochet hooks used for?
Steel hooks are used for crochet thread — size 10 cotton, lace yarn, or fine bedspread weight — for projects like doilies, filet crochet curtains, and decorative edgings. They use a reverse numbering system where higher numbers are smaller hooks. A Steel 6 or 7 is the standard starting point for size 10 thread.
Content reviewed by a fiber arts specialist with 30+ years of experience in knitting, crochet, and fiber arts education.