Which needle sizes do I need most?

The most commonly used sizes are 3.25mm (UK 10), 4mm (UK 8), and 5mm (UK 6). These cover DK, aran, and chunky yarns respectively. For sock knitting, 2.25-2.75mm are essential. Build your collection around the yarn weights you use most.

Should I buy straight or circular needles?

Circular needles are more versatile: they work for flat knitting, in-the-round, and magic loop. Many knitters now use circulars exclusively. An interchangeable circular set is the most cost-effective investment, covering many sizes with one purchase.

What is an interchangeable needle set?

Interchangeable sets include needle tips in multiple sizes and cables in multiple lengths that screw or click together. Popular brands include Chiaogoo, KnitPro, and Addi. They typically cost £50-120 and cover sizes 3.5-10mm, replacing dozens of fixed circulars.

Do I need DPNs if I have circulars?

Not necessarily. Magic loop technique on a long circular can replace DPNs for most projects. However, some knitters prefer DPNs for small circumference work like sock toes, glove fingers, and I-cord. Having a set in your most-used sizes is handy.

How do I convert between needle sizing systems?

UK sizes run opposite to metric (smaller number = larger needle). US sizes increase with metric. Key conversions: 4mm = UK 8 = US 6. 5mm = UK 6 = US 8. 3.25mm = UK 10 = US 3. Use the Needle Size Calculator for a full conversion table.

KnitCalcs

Needle Inventory Calculator — Track Sizes and Identify Gaps

Track which needle sizes you own and identify gaps in your collection for upcoming projects.

Needle Sizes Owned

Number of different sizes you own

Smallest Size Owned

Largest Size Owned

Needle Type

How We Calculate This

This calculator helps you assess your needle collection coverage and identify which sizes you may need to add.

Standard metric sizes

Standard needle sizes include: 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3.75, 4, 4.5, 5, 5.5, 6, 6.5, 7, 8, 9, 10, 12, 15mm.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard yarn weights and gauge. Results may vary with individual tension, yarn brand, and needle size.