The ribbing calculator

Do you struggle with getting ribbing evenly distributed across the garment? I do which is why I’ve created the ribbing calculator. An easy way to calculate the length of ribbing and get a great looking results without having to do the math yourself!

To get a nice looking result I always mark corresponding notches on the ribbing, so if my ribbing length is 85 percent of the garment length, I also make corresponding notches that are 85 percent of the garment. But that requires some numbers crunching which is why I came up with this calculator.

To get a nice looking result I always mark corresponding notches on the ribbing, so if my ribbing length is 85 percent of the garment length, I also make corresponding notches that are 85 percent of the garment. But that requires some numbers crunching which is why I came up with this calculator.

Ribbing calculator

Back of garment

Front of garment

Ribbing negative ease (%)


Ribbing length and notches

Total ribbing length

Mid back notch (MB)

Side seam notch (SS)

Mid front notch (MF)

Unsure how it works? Watch this short video to see the calculator in action:

Of course the calculator works for waist ribbing, fold over elastic and other stuff too that requires some type of stretched elastic. For more in depth info on how to calculate the best length of ribbing see my blog post Five tips on ribbing.