The best envelope size for a standard 5×7 card is an A7 envelope, which typically measures about 5.25 × 7.25 inches (5¼″ × 7¼″).

Quick Scoop

For a flat or folded 5×7 card, you generally want:

  • Envelope type: A7 invitation envelope.
  • Outer size: Roughly 5.25″ × 7.25″ (also listed as 5¼″ × 7¼″ or 14 × 19 cm).
  • Why this size: It gives about 1/8″–1/4″ clearance around the card so it slides in easily without being too loose.

What if the card is bulky?

If your 5×7 card has:

  • Layers, ribbon, wax seals, or thick embellishments,
  • Multiple inserts (RSVP card, info card, etc.),

you can size up slightly:

  • Look for “A7.5” style envelopes around 5.5″ × 7.5″ for extra room while still fitting a 5×7 card.

Simple rule of thumb

  • Card size: 5″ × 7″
  • Envelope size: About 1/8″–1/4″ larger on each side → A7 (5.25″ × 7.25″) is the standard match.

So if you’re shopping or searching online, look for “A7 envelopes for 5×7 cards” and you’ll get the correct size. ✅

Information gathered from public forums or data available on the internet and portrayed here.