Wedding thank you card sizes explained: A6, A5, square & postcard formats

1) The quick size guide (and when to use each)

A6 (148 × 105 mm)

A6 is the classic “postcard” footprint—compact, neat and economical. It’s ideal for:

• One strong hero photo on the front with a short printed message.
• Minimalist layouts with bold typography.
• Flat postcard formats when you want to keep weight (and often postage) down.

A5 (210 × 148 mm)

A5 gives you serious breathing room. It’s great when:

• You have a longer handwritten message for each guest.
• You want a folded card with a full-bleed photo outside and a clean, spacious inside.
• You’re considering including multiple images across front/inside/back.

Square (148 × 148 mm)

Square cards feel modern and keepsake-worthy. Choose square when:

• Your favourite image crops beautifully to a square, or you’re using a grid of photos.
• You want a distinctive look for display on a mantelpiece or noticeboard.
• You’re happy to balance style with practicalities (square formats can be a touch heavier or, with some couriers, a different postage tier).

Flat postcard vs folded greeting

Both formats are available across the sizes above. In short:

• Flat postcards: cost-effective, streamlined, and perfect for a strong front design with a short message on the reverse.
• Folded cards: traditional, roomy and lovely to write in, with inside space for longer notes and added photos.

2) Folded vs postcard: space to write, stocks to choose, practical posting

How much do you want to handwrite?

• Folded A5 is the spacious choice for proper thank-you notes. There’s room inside for a warm paragraph or two, and you can still include a printed message to save time.
• Folded A6 gives you the best of both worlds: a compact footprint with an inside panel for a short handwritten note.
• Flat postcards excel for succinct messages—think a printed “thank you” plus a quick line or two on the reverse.

Paper stocks and writing experience

All Utterly Printable cards are printed on FSC-certified, sustainably sourced card-stock. Choose from:

• House (350gsm, smooth-matt) – crisp and bright; easy to write on with most pens.
• Premium (324gsm, lightly textured) – a warm off-white Fedrigoni stock that feels artisanal; fountain pen-friendly.
• Photo Silk Touch (400gsm, light sheen; folded formats) – vivid photo reproduction with a silky finish; still excellent for writing inside.
• Super Thick (650gsm; flat cards) – double weight and tactile; perfect for luxe postcards that feel substantial in the hand.

Printing quality and finishing

Your photos are produced on Canon iX presses for rich, accurate colour. Folded cards are professionally scored before folding to prevent spine cracking, ensuring a clean finish that looks smart in any size.

Envelopes and postage

Quality envelopes are supplied with printed orders, with premium options available at checkout. As a rule of thumb, flat A6 is the most postage-friendly, A5 folded is larger and weightier, and square formats can sometimes sit in a different postage tier with some couriers. If you’re posting in bulk, it’s worth checking current rates for your chosen format. Note that postcards arrive unstamped; postage isn’t included.

3) What each size is best for (photos, layouts and wording)

A6: small, stylish, efficient

• Single photo hero: A full-bleed front image works brilliantly—especially with landscape shots of the two of you.
• Minimal message: Add a crisp “Thank you” and your names/date; pop a short line on the back (postcard) or inside (folded).
• Fast to write: If you’re sending 100+ notes, the smaller canvas helps keep handwriting time in check.
• When to pick it: You want a refined look with minimal fuss and straightforward posting.

A5: generous room for words (and extra photos)

• Handwritten notes: Ideal if you’d like to address gifts personally with a few sentences per guest.
• Photo-forward layouts: Showcase an epic portrait outside, then tuck candid shots inside for a lovely reveal.
• QR codes: Add a QR code linking to your digital photo gallery without crowding your message.
• When to pick it: You love the tradition of a folded card and have more to say than a postcard comfortably fits.

Square 148 × 148 mm: modern and mantle-friendly

• Grid collages: Square cards lend themselves to neat, symmetrical multi-photo grids.
• Editorial feel: A centred portrait or monochrome shot looks particularly chic in square.
• When to pick it: You’re after a contemporary keepsake guests will want to display.

5″ × 7″: balanced rectangle for photo/storytelling

• Photo flexibility: Works with both portrait and landscape shots without awkward cropping.
• Design freedom: Pair a bold image with a clear typographic “Thank you” and still leave room for names, date and a short message.

Flat postcard vs folded: folded: which suits your message?

• Flat postcard (A6, square or 5″ × 7″) – best for a succinct printed note and signature. It’s cost-effective and quick to address, especially once you settle on your final wording.
• Folded (A6, A5 or square) – best for personalised messages and extra images. Inside space is brilliant for thanking guests for specific gifts or including a short anecdote from the day.

Design help: single vs collage

If you’re set on sharing several photos, browse our dedicated range of photo collage wedding thank you cards. Many designs support multi-image layouts across front, inside and back at no extra cost, and you can upload as many images as you like in our browser-based editor. For a clean, single-photo look, try a bold full-bleed front with a simple line of text below.

Production, samples and turnaround

Every order is printed in the UK on FSC-certified stocks, with an option to download a high-resolution PDF if you prefer to print locally or send digitally. If you’d like to see colour and paper in hand before committing, order a printed sample of your design. Delivery is fast: standard 3 working days, or 1–2 day express for UK Mainland (order by 6 pm). Carbon-offsetting is available at checkout.

Coordinating your stationery

If you’re building a cohesive suite, we’ve got you covered—from wedding order of service templates that echo your fonts and colours to personalised wedding table plans to tie your reception look together. You can return to your saved design and make edits right up until printing begins.

Ready to choose a size?

Explore and personalise your favourite design in minutes in our browser-based editor. Start browsing our full range of wedding thank you card templates, try a photo-forward layout from the photo collage collection, and co-ordinate the rest of your suite with matching order of service designs and personalised table plans.