Family Stem Weights Calculator
Use this calculator to work out the weight progression of your typeface. This is meant to be a starting point, so refine and tweak as needed.
Linear progression
Luc(as) progression
Impallari progression
Based on Pablo Impallari's Family Stem Weights Calculator, currently offline. Pablo's formula is an average between a linear progression and Luc(as) de Groot's formula.
This is a project from The Diacritics Club, a casual type meetup in London.