Lined envelopes are offered in 3 sizes

• A7 lined envelopes are 5 1/4 x 7 1/4 and is the perfect choice for an A7 card dimensions 5 1/8 x 7. This is a typical invitation card size.
• A9 Lined Envelopes are 5 3/4 x 8 3/4 and is the perfect choice for a half sheet. Many people like the convenience of printing their invitation cards at home using an 8 1/2x11 sheet and cutting in half after printing.
• 6 1/2 Square lined envelopes are just that, 6 1/2 x 6 1/2 square. The perfect card is 6 1/4 square. This is a great choice for an upscale contemporary invitation. However be aware that all square envelopes mailed in the USA will require extra postage. You can read more about this here. Do Square Envelopes Require Extra Postage 

Shop Lined Envelopes Here:

A7 Lined Envelopes

A9 Lined Envelopes

6 1/2 Square Lined Envelopes