Mailing a card or letter seems simple, but there are many different options to choose from when it comes to cards and their envelopes.
Picking the right envelope can help you save on postage and will ensure that whatever you’re mailing arrives safely.
Getting a feel for the dimensions of an A6 envelope can help you determine if it’s the right option.

A6 Envelope Length, Width, and Thickness
An A6 envelope has a height of 4.75 inches or about 12 centimeters and a width of 6.5 inches or about 16.5 centimeters. The inside of the envelope has a slightly smaller perimeter size than the outside, and the inside dimensions are often between 0.2 and 0.5 inches smaller all around.
All envelopes have a different thickness depending on what they’re designed for and what type of paper they are made out of.
Because of this, it’s hard to say exactly how thick any given envelope will be. Most envelopes, however, are about 0.25 inches thick. This is equal to about 6.35 millimeters.

A6 Envelope Weight
It’s difficult to say what an A6 envelope will weigh exactly because these envelopes can be made of so many different types of paper, and thicker papers will add more weight.
If the paper overlaps more inside the envelope, this can also add weight. However, most A6 envelopes weigh between 0.18 and 0.25 ounces or between about 5 and 7 grams.
What you intend to mail will determine how heavy the envelope and its contents are overall, but since A6 envelopes were designed to hold only small items, it’s relatively easy to estimate postage cost.
A6 envelopes measure 4.75″ x 6.5″ and weigh 5-7 grams.
In the United States, one forever stamp will cover a letter or card weighing up to 1 ounce or about 28.35 grams, so even if whatever you’re putting in the A6 envelope is thick or takes up several sheets of paper, it will still most likely only need one forever stamp.
If you feel the envelope and its contents are too light for a forever stamp, you can use smaller stamp denominations that add up to the envelope’s specific weight.

What is an A6 envelope used for?
A6 envelopes are most commonly used for greeting cards, invitations, thank you cards, or announcements.
Many people choose A6 envelopes to send a picture, printed on card stock, announcing a birth or engagement.
Other people use these envelopes for weddings, birthday parties, or graduation invitations, while others choose this size to send out their holiday cards.
Pictures can also be placed in an A6 envelope, as it offers just enough space for the pictures without crimping the edges.
An A6 envelope can also hold a letter or note written on notepaper.

Choosing the Right Envelope
Before choosing an envelope, it’s important to choose the size of the card or photo you want to send.
Make sure that the envelope is large enough that you won’t need to bend the card to get it in, and also ensure that it’s easy to remove the card or pictures from the envelope.
If you’re sending several pictures or a card or letter that’s quite thick, you may want to opt for a thicker or more durable envelope paper.
This helps to ensure that whatever you’re mailing will make it to its destination safely.
However, thicker envelope paper can be more expensive, raising the overall price of the envelope, and this can be a factor if you’re ordering envelopes and cards in large quantities.
The back flap of the envelope is also something to consider. A6 envelopes can have a wallet flap, also called a square flap, or a triangular flap.
Traditionally, wallet flaps are more formal, while envelopes with triangular flaps are used for more casual occasions.
