Short answer: download the one-page Letter PDF with Part A and Part B amounts for 1:1, 2:1 and 3:1 by volume, from 2 to 64 fl oz, in fl oz and ml, plus a blank batch line. Free, no signup.
Mixing by weight? Volume and weight ratios differ; use the volume-to-weight converter. Selling your pieces? See the printable Resin Business Planner in our Etsy shop.
By volume. Weight ratios differ because hardener is usually lighter than resin; convert with the weight converter.
It's on the label or technical data sheet. Many art and tabletop resins are 1:1; many deep-pour and casting resins are 2:1 or 3:1.
It's Letter size; choose 'fit to page' when printing on A4.
More tools: resin calculator · mix ratio by weight · cure time · mold volume · tabletop coating · pouring too thick