Free Crochet Hook Size Converter
Crochet hook sizes are labeled differently around the world — US letters, UK numbers, and Japanese sizing. This converter shows the exact metric (mm) equivalent across all major systems at a glance.
Crochet Hook Size Converter
Complete Size Reference Chart
| Metric (mm) | US | UK (old) | Japanese | Used In |
|---|---|---|---|---|
| 2 mm | — | 14 | — | UK ·
Europe Russia · China · India · AU/NZ |
| 2.25 mm | B/1 | 13 | B/1 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 2.75 mm | C/2 | 12 | C/2 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 3 mm | — | 11 | — | UK ·
Europe Russia · China · India · AU/NZ |
| 3.25 mm | D/3 | 10 | D/3 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 3.50 mm | E/4 | — | E/4 | US · JP ·
Europe Russia · China · India · AU/NZ |
| 3.75 mm | F/5 | 9 | F/5 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 4 mm | G/6 | 8 | G/6 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 4.50 mm | 7 | 7 | 7 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 5 mm | H/8 | 6 | H/8 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 5.50 mm | I/9 | 5 | I/9 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 6 mm | J/10 | 4 | J/10 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 6.50 mm | K/10.5 | 3 | K/10.5 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 7 mm | L/11 | 2 | L/11 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 8 mm | M/13 | 0 | M/13 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 9 mm | N/15 | 00 | N/15 | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 10 mm | P/Q | 000 | P/Q | US · UK · JP ·
Europe Russia · China · India · AU/NZ |
| 11.50 mm | Q | — | Q | US · JP ·
Europe Russia · China · India · AU/NZ |
| 12 mm | S | — | — | US ·
Europe Russia · China · India · AU/NZ |
| 15 mm | T | — | — | US ·
Europe Russia · China · India · AU/NZ |
| 16 mm | U | — | — | US ·
Europe Russia · China · India · AU/NZ |
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About the Crochet Hook Size Converter
A crochet hook size converter translates between US letter, UK, Japanese, and metric sizing systems. Hook sizes vary by country and manufacturer — this converter ensures you pick the right hook for any pattern.
Quick Start Guide
- Enter your values — Fill in the fields with numbers relevant to your crochet hook size calculation. Most fields include sensible defaults.
- Adjust settings — Change options like units, rates, or timeframes to match your specific scenario.
- Review results — The output shows a clear breakdown so you understand how the total was calculated.
How It Works
Maps crochet hook sizes across US (B/1 through T/X), UK (14 through 000), Japanese (2/0 through 10), and metric (2.0mm through 25.0mm) systems. Includes a complete reference chart.
Real-World Example
Scenario: Converting a US crochet pattern to metric
- Pattern calls for: US Size H/8.
- Metric equivalent: 5.0 mm.
- UK equivalent: Size 6.
Who Is This For?
This crochet hook size converter is designed for Students, professionals, and anyone who needs quick, accurate conversions and calculations for everyday tasks.. It's intentionally simple — no complex signup forms, no data tracking, no distractions. Just enter your numbers and get the answer.
Pro Tip
Bookmark this tool for quick access — you will use it more often than you think.
Things to Know
The crochet hook size converter provides instant, accurate results based on standard formulas and the values you enter. Whether you are planning a financial decision, tracking a health metric, or solving a practical problem, this tool gives you the numbers you need without requiring signup or account creation.
How to get the best results: Use accurate, up-to-date inputs for the most reliable calculations. When planning ahead, run multiple scenarios with different assumptions to understand the range of possible outcomes.
Note: This tool is designed for educational and planning purposes. For critical financial, medical, or legal decisions, always verify the results with a qualified professional who can evaluate your specific circumstances.
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Frequently Asked Questions
Is there a limit on how many times I can use this?
No limits at all. Use it as many times as you need, completely free.
Does this work on mobile devices?
Yes. The tool is fully responsive and works on smartphones, tablets, and desktop browsers.
How accurate are the results?
Results are based on standard formulas and the values you enter. They are accurate for educational and planning purposes.
Is this tool really free?
Yes, completely free. No signup, no hidden charges, no usage limits. Use it as often as you need.
Can I share the results?
Yes. You can take a screenshot or share the page link with anyone. The tool works the same for everyone.