Wedding invitation size is one of the few stationery decisions that changes your costs, your envelope options and your postage all at once. Pick 5 x 7 and everything downstream is standard and cheap. Pick square and you pay a surcharge on every piece you mail.

This guide gives every dimension in inches first with millimeters in brackets, the envelope that fits each card, and the postal consequence of each choice. All measurements are verified against paper suppliers and USPS rather than repeated from other blogs.

What size are wedding invitations?

Most are 5 x 7 inches (127 x 178 mm). That is the default across the US wedding industry, because it holds a full formal wording block, pairs with a widely stocked envelope, and stays inside standard letter postage.

Portrait is the default, but 7 x 5 inches works just as well and reads as more modern. Our printable wedding invitation templates are built at 5 x 7 inches, which keeps them compatible with A7 envelopes sold in any craft or stationery shop.

Are wedding invitations A5 or A6?

Neither, if you are in the US. A5 and A6 are ISO metric paper standards used in the UK, Europe and Australia, while US invitations are measured in inches and do not correspond exactly to any A size.

The closest comparisons are useful to know. A6 sits between the US 4 x 6 and 4.25 x 5.5 sizes. A5 is noticeably taller and narrower than 5 x 7, so an A5 card will not sit properly in an A7 envelope.

A warning about the letter A

The US and ISO systems both use the letter A, and they mean entirely different things. A US A7 envelope is 5.25 x 7.25 inches (133 x 184 mm). An ISO A7 sheet is 2.91 x 4.13 inches (74 x 105 mm), barely bigger than a business card.

If you are ordering from a supplier outside the US, confirm whether their A numbers refer to envelopes or to ISO paper before you buy 120 of anything.

What size should each piece in the suite be?

Within the mailed suite the invitation is the largest piece, with enclosure cards one size down and reply cards smaller again, so everything stacks neatly inside one envelope. Day-of pieces such as menus and programs are sized independently, because they are never mailed.

Two sizing notes worth acting on. Our RSVP cards are 5 x 3.5 inches, which is exactly the USPS minimum mailable size and qualifies for the cheaper postcard rate. And our save the dates come at 5 x 7, 7 x 5 and 4 x 6, so you can match the invitation or deliberately go a size down.

If you want every piece proportioned to the others without checking each one, wedding invitation suites are designed as a set. A five piece wedding invitation sets bundle covers the invitation, details card, reply card and the two envelopes in one consistent scale.

Which envelope fits which invitation size?

The envelope needs to be about a quarter inch larger than the card in both directions. That clearance is what lets the card slide in and out without bending, and it is why a 5 x 7 card needs a 5.25 x 7.25 envelope rather than a 5 x 7 one.

Pairings verified against PaperPapers and CutCardStock, both paper and envelope suppliers rather than stationery retailers. A 4 x 6 card also fits an A6 comfortably, with slightly more clearance than the 4.5 x 6.25 the size was designed around.

Square envelopes are the exception to the quarter inch rule in practice. Allow at least a quarter inch on a square, since there is no long edge to guide the card in and a tight fit becomes genuinely difficult to use.

Does invitation size affect postage?

Yes, and more than most couples expect. USPS letter standards require a mailpiece to be at least 3.5 inches high by 5 inches long, no more than 6.125 by 11.5 inches, and to have an aspect ratio between 1.3 and 2.5. Anything outside that pays a surcharge or a higher class of postage.

Rates effective 12 July 2026 per USPS. A First-Class stamp is $0.82, each additional ounce adds $0.29, and the non-machinable surcharge is $0.49.

A square envelope has an aspect ratio of 1.0, which falls outside the machinable range by rule, so the surcharge applies even to a light, thin square. Across 120 invitations that is $59 for the shape alone.

One detail almost nobody checks: an A2 reply envelope has an aspect ratio of 1.31, barely inside the machinable window. It passes, but there is no margin in it, so do not have reply envelopes custom cut any squarer than standard.

How much wording fits on each size?

Size decides how much you can say without shrinking the type below comfortable reading size. At a normal 10 to 12 point body size, the practical limits look like this.

The trap at the large end is different from the trap at the small end. A 4 x 6 card with too much on it looks cramped, but a 5.5 x 8.5 card with a short casual wording looks unfinished.

How do you choose the right size?

Start from your wording, not your design. Write the full text first, then pick the smallest size that holds it comfortably, because every increase in size costs more in paper, printing and often postage.

●     More wording needs more space. Two sets of parents on the host line usually rules out 4 x 6.

●     Larger sizes cost more throughout. More paper per card, and 5.5 x 8.5 suites often cross into a second ounce.

●     Non-standard sizes limit envelopes. Odd dimensions mean custom envelopes, longer lead times and no local restocking if you spoil a few.

●     Square costs $0.49 extra per piece. Worth it if the design depends on it, not worth it by default.

●     Match the suite, do not mix systems. An ISO A5 invitation with US A7 envelopes will not fit.

If you are printing from a template

Set the file up a quarter inch larger than the finished size to allow an eighth of an inch of bleed on every edge, so a 5 x 7 card is built at 5.25 x 7.25 inches. Keep all text at least an eighth of an inch inside the trim line, or a slight cutting shift will clip it.

What size should digital invitations be?

A 9:16 vertical ratio, which is the full-screen shape on a phone. Digital invitations are not measured in inches at all, because there is no paper and no trim.

Design at 1080 x 1920 pixels for that ratio and the invitation fills the screen in a message, an email preview or a story post without cropping. A 5 x 7 print file sent digitally will have a letterbox with white bars down both sides.

Frequently Asked Questions

Are wedding invitations A5 or A6?

Neither, in the US. A5 and A6 are ISO metric standards used in the UK, Europe and Australia. A5 is 5.83 x 8.27 inches (148 x 210 mm) and A6 is 4.13 x 5.83 inches (105 x 148 mm). US invitations are measured in inches, most commonly 5 x 7.

Are most wedding invitations 5x7?

Yes. It is the standard US size because it holds a full formal wording block at readable type size, pairs with the widely stocked A7 envelope, and stays within regular letter postage at $0.82 for one ounce. Nothing about it requires a special order.

Is a 4x6 invitation too small?

No, but it limits your wording. A 4 x 6 card (102 x 152 mm) comfortably holds names, date, time, venue and a closing line. Two sets of parents on the host line will feel cramped. It suits casual weddings and costs less in paper and printing.

What size is a 5x7 invite?

Five inches wide by seven inches tall, or 127 x 178 mm. It mails in an A7 envelope measuring 5.25 x 7.25 inches (133 x 184 mm), which allows the quarter inch of clearance needed to slide the card in and out without bending a corner.

What size are wedding invitations?

Most are 5 x 7 inches (127 x 178 mm). The other standard options are 4 x 6 (102 x 152 mm) for casual weddings, 4.25 x 5.5 (108 x 140 mm) for showers and smaller events, and 5.5 x 8.5 (140 x 216 mm) where the wording runs long.

What size envelope do I need for a 5x7 invitation?

An A7 envelope, also sold as a Lee envelope, measuring 5.25 x 7.25 inches (133 x 184 mm). The extra quarter inch across both dimensions is deliberate clearance. A true 5 x 7 envelope would grip the card and damage the corners on insertion.

What size should save the dates and RSVP cards be?

Save the dates are usually 5 x 7 or 4 x 6 inches, matching the invitation or one size down. Reply cards are commonly 5 x 3.5 inches (127 x 89 mm), which is the USPS minimum mailable size and qualifies for the postcard rate.

Does invitation size affect postage?

Yes. Square and oversized invitations are non-machinable, which adds a $0.49 surcharge per piece regardless of weight, taking a one ounce square from $0.82 to $1.31. Rates effective 12 July 2026. Anything over 6.125 x 11.5 inches is rated as a flat instead.

Ready to choose your size?

Write your wording first, pick the smallest size that holds it, then check the envelope and the postage before you order anything. Browse our wedding invitation and stationery templates to see every piece already sized to fit together, with print-ready files set up at the right dimensions and bleed.