Here's a table with the weights of the Stampin' Up! cardstock and designer paper, plus a guide for what to use for different project types...

Stampin' Up! Product

Basis Weight

Uses

Lightweight Designer Series Paper

100-110 gms

Envelopes, lightweight paper layers, and embellishments

Designer Series Paper

145-160 gsm

Paper layers, envelopes and embellishments

Card Stock

200-240 gsm

Greeting card bases, paper layers, embellishments, boxes, and packaging

Thick Card Stock
(available in Whisper White and Very Vanilla)

250-280 gsm

Greeting card bases, boxes, and other packaging

Watercolor Paper
(100% cold-pressed cotton paper)

300 gsm

Water-colouring and water-based techniques

Note, all Stampin' Up! card stock is acid free and lignin free, so you can feel confident using it with your memory keeping projects.