Paper weights explained: 250gsm vs 600gsm cotton

GSM means grams per square meter. Standard invitation card is 250–300gsm — sturdy, mails well. 600gsm cotton is double-thick, letterpress-grade, with a soft tactile edge clients associate with luxury.

Heavier is not always better: 600gsm needs higher postage and can't be folded. Use 250–350gsm for pocketfolds and multi-piece suites, 600gsm for single statement cards.