Envelope Size Guide
Complete envelope size reference with dimensions for business, personal, invitation, and catalog envelopes.
#6 3/4
PersonalPersonal letters, reply envelopes
Letter rate
#9
BusinessInvoices, business letters (tri-fold 8.5x11)
Letter rate
#10
BusinessStandard business envelope (tri-fold 8.5x11)
Letter rate
#10 Window
BusinessBills, invoices with visible address
Letter rate
#12
BusinessCatalogs, reports, legal documents
Letter rate
A2
InvitationRSVP cards, thank you notes
Letter rate
A6
Invitation4x6 photos, invitations
Letter rate
A7
Invitation5x7 invitations, greeting cards
Letter rate
A9
InvitationLarge invitations, announcements
Letter rate
6x9
CatalogBooklets, catalogs (half-fold 8.5x11)
Flat rate
9x12
CatalogFull-size documents, 8.5x11 unfolded
Flat rate
10x13
CatalogLarge documents, magazines, manuscripts
Flat rate
12x15.5
CatalogLarge flat documents, prints
Flat rate
Envelope Size Reference
The #10 envelope is the standard US business size. USPS letter rate requires envelopes between 3.5x5 and 6.125x11.5 inches, under 3.5 oz and 0.25 inch thick.
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Disclaimer: This tool is provided as-is for informational and educational purposes only.