what size is a g crochet hook

A G crochet hook is usually about 4.0 mm in diameter, though some brands label G hooks as 4.25 mm.

Quick Scoop

• The most common answer to “what size is a G crochet hook” is:
  • G-6 = 4.0 mm.

• Some charts and brands also list:
  • G = 4.25 mm (often seen in extended size charts or older hooks).

• In practice, both 4.0 mm and 4.25 mm hooks may be marketed as “G,” which is why patterns sometimes just say “G (4.0 mm).”

Why There’s Confusion

• Different standards : The Craft Yarn Council standard commonly treats G as 4.0 mm , but some manufacturers have used 4.25 mm, and some charts list both under G ranges.

• Brand variation : Crocheters often report that older G hooks measure 4.0 mm and some newer ones measure 4.25 mm, even within the same labeled size.

• Real-world tip : Many crocheters recommend using the millimeter size in the pattern (if given) and matching it with your hook, rather than relying on the letter alone.

Mini FAQ (2026 context)

• Q: If a pattern just says “G hook,” what should I reach for?
  Use a 4.0 mm hook first, since that’s the widely accepted standard today.

• Q: When would I use 4.25 mm as G?
  Some hook sets and older charts include a 4.25 mm labeled G; if your gauge is a bit tight with 4.0 mm, stepping up to 4.25 mm can help meet gauge while still being “G-ish.”

So, in everyday terms: when someone asks “what size is a G crochet hook,” the safe, modern answer is G = 4.0 mm , with the caveat that a few hooks labeled G may be a slightly larger 4.25 mm.

TL;DR:
G crochet hook = 4.0 mm in most current standards; sometimes you’ll see G offered as 4.25 mm , so always check the mm size and your gauge.

Information gathered from public forums or data available on the internet and portrayed here.