Calculate Tension and Needle Size
When Holding Multiple Strands Together

Tension Calculator:
Estimate the Tension of Your Yarn Combination

When combining two strands of yarn (either two strands of the same yarn or two different types), it can be challenging to predict the resulting thickness and tension. However, this significantly impacts your finished project.

This tension calculator considers the length and weight of your yarns, matches them with standard yarn weight categories, and provides a recommended tension and needle size for you!

How to use the calculator:

Follow these four steps to estimate the recommended tension when holding two strands of yarn together.

Select yarn combination: Indicate whether you're using two strands of the same yarn or two different yarns.
Enter yarn details: For each strand, input the length (metres per skein) and weight (grams per skein).
Enter pattern specifications (optional): Provide the recommended needle size and tension from your pattern.
Calculate: Click "Calculate" to receive an assessment of yarn weight category, tension, and needle size.

Things to note

This calculator is based on standard stockinette stitch and offers a guideline.

Tension may vary, for example:

If you're knitting textured patterns, lace, cables, or ribbing
If you're using special yarns like blow yarn, mohair, or bouclé
If you're combining very airy or elastic yarns

Always knit a tension swatch to ensure the desired look and fit of your finished project.

Planning to Knit with Multiple Strands?
Estimate the Recommended Tension!

What is a Yarn Weight System
– and Why Does It Matter?

The Yarn Weight System is a standardised way to classify yarns based on thickness and tension. Each category covers a range of lengths per 100g, stitches per 10 cm, and recommended knitting needle and crochet hook sizes.

Knowing the yarn weight category helps you find substitutes or combine yarns that match in thickness. This is especially useful if you're using a different yarn than specified in the pattern or combining multiple strands and want to know their equivalent thickness.

Yarn weight categories are widely used in both knitting and crochet patterns, providing a solid foundation when planning your project.

Yarn Weight Category Overview

Yarn Weight	Length per 100g	Tension (10 cm)	Knitting Needle	Crochet Hook
Lace	Over 700m	33–40 stitches	1.5–2.25 mm	1.5–2.25 mm
Super Fine	550–700m	27–32 stitches	2.25–3.25 mm	2.25–3.25 mm
Fine	425–549m	23–26 stitches	3.25–3.75 mm	3.25–4 mm
Light (DK)	325–424m	21–24 stitches	3.75–4.5 mm	4.5–5.5 mm
Medium (Worsted)	240–324m	16–20 stitches	4.5–5.5 mm	5.5–6.5 mm
Bulky	160–239m	12–15 stitches	5.5–8 mm	6.5–9 mm
Super Bulky	100–159m	7–11 stitches	8–12.75 mm	9–15 mm
Jumbo	Under 100m	1–6 stitches	12.75+ mm	15+ mm

Source: Craft Yarn Council, www.yarnstandards.com

What Do the Different Yarn Weight Categories Mean?

Lace: Very fine yarn (over 700 m/100g), perfect for shawls, light scarves and lace patterns. Also used as a companion strand, e.g. silk mohair.
See e.g. Fraya Friendly, Fraya Charming and Fraya Twinkly
Super Fine: Thin yarn (550–700 m/100g), ideal for socks, baby clothes and lightweight tops. Creates a fine and delicate texture.
See e.g. Fraya Mindful
Fine: Light yarn (425–549 m/100g), suitable for jumpers, T-shirts/tops, children’s clothes and colourwork. Often knitted on 3–4 mm needles.
Light (DK): Versatile yarn (325–424 m/100g), popular for cardigans, blouses and accessories. Perfect for both stockinette and textured stitches.
See e.g. Fraya Cosy and Fraya Delicate
Medium (Worsted): Medium-weight yarn (240–324 m/100g), ideal for winter knits, jumpers and blankets. Provides warmth without heaviness.
See e.g. Fraya Caring, Fraya Delightful, Fraya Fluffy and Fraya Thoughtful
Bulky: Thick yarn (160–239 m/100g), great for volume and warmth. Ideal for chunky knits, hats and throws.
See e.g. Fraya Comfy, Fraya Wavy and Fraya Happy
Super Bulky: Very thick yarn (100–159 m/100g), perfect for puffy projects like blankets, oversized cardigans and home knits.
See e.g. Fraya Honest
Jumbo: Extremely thick yarn (under 100 m/100g), for large knitting needles or crochet hooks. Ideal for cushions, blankets or even bags. Gives an ultra-chunky, decorative look.
See e.g. Fraya Cheerful

Frequently Asked Questions About
Yarn Weight and the Gauge Calculator

How does the gauge calculator work?

The gauge calculator converts your yarn information into metres per 100g, calculates a combined length, and matches it with standard yarn categories. You then receive a suggested gauge and needle size, along with a recommendation if you've entered pattern specifications.

What should I do if my gauge doesn’t match?

You can try adjusting your needle size. If you get too few stitches per 10 cm, try a smaller needle. If you get too many, go up a needle size.

→ Get help in our guide to swatching and gauge

Do I really need to knit a swatch?

Yes, always! The calculator gives you a guideline only—not a guarantee. Everyone knits differently, and the fibre composition and properties of your yarn may differ from those used in the pattern.

→ Learn how to make a swatch

→ Read about yarn fibres and blends

Where can I find the yarn length and weight?

It’s listed on the yarn label, e.g. “210 m / 50 g”. You’ll also find this information on the product page in our webshop.

What is a Yarn Weight Category?

Yarn weight categories are a way to classify yarns by thickness and length. Each group has a typical range for gauge and needle size. This helps you find alternative yarns or assess if a yarn combination is suitable for your pattern.

Calculate Tension and Needle Size
When Holding Multiple Strands Together