Waist Shaping: The Math, Hem to Hip

Don't be scared. I know it says "math" in the title, but it's knitting math, so we can handle it, right? (Fearless knitters and all that.) Plus, we'll go slow, we'll do this in stages, you can ask questions, and there are no stupid questions, ever. OK. Now that you know the basic concepts behind waist shaping, let's talk some numbers.

Waist shaping on a simple shirt: Hem to hip

We'll do the math for a theoretical sweater for myself, using my battered-and-beloved copy of Ann Budd's Knitter's Handy Book of Sweater Patterns as a template. I'll start with the charts for a basic pullover, modified to be worked in the round.

Remember, this is a theoretical sweater, folks. No time to knit an actual sweater, but that's OK. It's just to illustrate The Numbers.

Gauge Swatch:
Yes, indeedie, I must theoretically knit a theoretical gauge swatch, because I need to know two numbers: stitches per inch, and rounds per inch.
Gauge: 7 stitches per inch and 13 rounds per inch.

For this part I need to know: hip circumference, hem-to-hip length, and the all-important Desired Ease. For ease, I'd like something body-skimming, but not tight. (No negative ease this time.)
Hips: 44" I measure this with my handy tape measure.
Hem-to-hip length: 2" I choose this based on the pattern and garment shape.
Ease: 1.5" (positive) ease I choose this based on how I like to wear garments of a similar style.

How many stitches to cast on?
Add together hip measurement and ease: 44" plus 1.5" equals 45.5".
Multiply by gauge: 45.5" times 7 sts per inch equals 318.5 sts.
Round up: 319 stitches to cast on at lower hem.

What to do next?
I start knitting! I work even over those 319 stitches for 2" (see hem-to-hip length, above), which works out to 26 rounds (2" times 13 rounds per inch).

Once I have finished those 26 rounds, I have reached my widest bit. It is time for the decreases to begin!


Sandi Wiseheart is the founding editor of Knitting Daily. She is now the author of the popular Knitting Daily blog: What's on Sandi's Needles.


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18 thoughts on “Waist Shaping: The Math, Hem to Hip

  1. I’m loving the discussions about shaping, but one thing I’d really like to learn more about is lengthening the body of a sweater. I find most sweater patterns to be just a little too short for me. What can I do to ensure I get a hip length sweater with waist shaping in the right place?

  2. Terrific, Sandi. This is just so valuable, and the perfect application of the internet. I can’t compliment you enough on your virtual imaginary KAL.
    Thank you.

  3. Um, Sandi? Are you doing a pattern at the bottom of this hypothetical sweater? or just straight ahead Ks? Something with a pattern of 11 or 29 stitches? (BTW – love your work – writing and knitting)

  4. I think I am really going to like this pattern. We will be able to see it grow as we go along.

    I have the opposite problem from samantha F. I am short and would love to know how to make curves fit smoothly over a shorter space.

  5. This truly excellent series of tutorials is going to get me back into knitting sweaters (my first love of knitting) following two fitting disasters in a row that had me swearing off them forever! I cannot thank you enough!

  6. This is brilliant. I’ve been wanting to try to adjust patterns, and had even started a sweater, but hadn’t been quite fearless enough to trust my own assumptions (I’m working on it!). It’s so nice being validated.

  7. Sandi, I wanted to let you know that mostly due to your clear explanations and the great galleries, I frogged and reknit a sweater that now fits me. You have given the me the courage to knit with negative ease. Thank you

  8. Sandi, I wanted to let you know that mostly due to your clear explanations and the great galleries, I frogged and reknit a sweater that now fits me. You have given the me the courage to knit with negative ease. Thank you

  9. Ok, ok, this I’m starting to see how this could really be useful in helping me to a) design my own sweater and b) alter a pattern to make it more fitting to my figure (think big boobs on a stick–if it’s big enough to cover my boobs, it hangs lifelessly from the rest of my body). The question I have, comes down to necklines and figuring out the measurements/no. of stitches for various necklines. I’m a top down in the round knitter, rather than bottom up, so I could just experiment until I get it right, but if there’s someone with experience and an easier way to figure the neckline, I’d love to hear it!

  10. Sandi – thanks so much for continuing this series! Despite us never having met before, I’m feeling like you’re my own personal knitting guru. You have a gift for sharing info in a lighthearted yet practical & easily understood way that really helps me to be more fearless.

  11. Thanks so much for this series Sandi! We all need this kind of basic info, unless we’ve taken the time to sort it all out ourselves. I’ll bet most of us haven’t. I know I haven’t in my over 30 years of knitting. Thanks again and keep up the good work!