Question 1

What is a US F/5 crochet hook in UK sizes?

Accepted Answer

A US F/5 hook is 3.75 mm, which maps to approximately old UK size 9. UK conversions are approximate — millimeters are the reliable measurement, so check the mm size on your hook.

Question 2

What is the difference between US and UK crochet terms?

Accepted Answer

UK terms are one step 'up': a US single crochet (sc) is a UK double crochet (dc), a US double crochet is a UK treble (tr), and a US half double crochet is a UK half treble (htr). Always check a pattern's origin before starting.

Question 3

What size crochet hook for worsted weight yarn?

Accepted Answer

Worsted (#4 medium) yarn typically pairs with hooks I/9 to K/10.5 (5.5–6.5 mm). Check your yarn label and swatch for gauge-critical projects.

Question 4

How do I convert a crochet hook size?

Accepted Answer

Type any format into the quick converter — "5mm", "H/8", or "UK 6" — and it shows the metric, US, and old UK/Canadian equivalents plus the yarn weights that hook pairs with. Millimeters are always the controlling size.

US Term		UK Term
slip stitch (sl st)	↔	slip stitch (sl st)
chain (ch)	↔	chain (ch)
single crochet (sc)	↔	double crochet (dc)
half double crochet (hdc)	↔	half treble (htr)
double crochet (dc)	↔	treble (tr)
treble crochet (tr)	↔	double treble (dtr)

LTK Cuties Crochet Hook Size Chart — US, UK & mm Conversion

Hook Size Conversion Chart

Yarn Weight Guide

Quick Converter

US vs UK Crochet Terms

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