A4 Paper Size Guide for Packaging Dielines & Printing Templates

Author | Date: 10/18/2025

Ask any packaging designer what sheet size they start with, and chances are they’ll say A4. It’s the sheet everyone has — quick to print, easy to fold, and ideal for testing dielines before scaling up.

But here’s the twist: most people know A4 from the office printer, not the packaging studio. In packaging, that 210 × 297 mm sheet is more than a standard — it’s a starting point. From dieline layouts to printable mockups, A4 helps designers, printers, and small brands visualise structure, check fit, and get client approval without wasting full sheets of board.

In this guide, you’ll learn what A4 actually measures, why it’s used so heavily in packaging design, how to prep A4 print templates correctly, and when to move beyond it.

What Exactly Is A4 Paper Size?

Let’s start simple.

A4 measures 210 × 297 millimetres — or roughly 8.27 × 11.69 inches — making it part of the global ISO 216 A-series paper system. That “A” isn’t random; it defines an aspect ratio of √2:1, meaning you can halve or double it and still maintain the same proportions.

🔎 PAA Answer

Is 8.5 × 11 the same as A4?

No. US Letter is slightly wider/shorter. Always confirm the intended sheet size before printing dielines.

🎉 Fun Fact

This consistent ratio is why designers love it — an A4 dieline can scale perfectly to A3 or A5 without distorting your layout.

If you’re in the UK, A4 is the default size for office printers, sample proofs, and dieline mockups. In the US, however, people often confuse it with “Letter” size (8.5 × 11 in). They’re close, but not identical — A4 is a bit taller and narrower, which can throw off margins if you print across regions.

🔎 PAA Answer

What size is A4 paper UK?

The UK follows ISO 216, so A4 is the same: 210 × 297 mm.

💡 Pro Tip

Always check whether your client is sending A4 or Letter artwork — a small mismatch can nudge your dieline out of alignment when printed.

Why A4 Is the Designer’s Friend?

Designers don’t use A4 just because it’s handy — they use it because it’s smart.

Here’s why A4 sheets are the go-to in packaging workflows:

Printer-friendly: Works on nearly every desktop or studio printer.
Great for mockups: Perfect for folding quick structural samples.
Ideal for testing: Use A4 to check glue tabs, closure depth, or flap overlap before committing to production.
Client-ready: Present realistic prototypes on A4 proofs — much better than showing digital renders alone.

Even in Adobe Illustrator, A4 is the default artboard for dieline work because it’s versatile enough to host most small box types.

🔎 PAA Answer

How big is A4 size paper?

It sits between A3 and A5: compact enough for desktop printing, large enough to prototype small cartons.

Using A4 Sheets for Dielines and Mockups

Every dieline starts as a flat shape — a blueprint for where to cut, fold, and glue. And when you’re experimenting with structure, A4 is the perfect playground.

Designers often start by fitting dielines for:

Soap or skincare cartons
Chocolate or jewellery boxes
Mini mailer boxes for samples
Sleeve wraps or belly bands

A4 templates help you see how panels fold, whether logos align at the seams, and if there’s enough space for inner supports.

🔎 PAA Answer

What does A4 stand for in paper?

It’s the fourth size in the ISO 216 A series with a √2 aspect ratio, enabling perfect scaling between A sizes.

💡 Pro Tip

Always add a 3 mm bleed to every dieline edge and print at 300 DPI in CMYK mode. Even on test sheets, consistency counts — what looks right on paper should print right at scale.

How Big Is A4 in Different Units?

You’ve probably seen A4 listed in all kinds of measurements. Here’s how it translates:

Measurement Type	A4 Dimensions
Millimetres (mm)	210 × 297 mm
Centimetres (cm)	21.0 × 29.7 cm
Inches	8.27 × 11.69 in
Pixels (300 DPI)	2480 × 3508 px

🔎 PAA Answer

What is the size A4 in cm and inches?

A4 is 210 × 297 mm — or 21.0 × 29.7 cm / 8.27 × 11.69 inches.

So if a client asks for the dimension of A4 paper in inches or in cm, you can answer confidently.

🔎 PAA Answer

What are the dimensions of A4 size paper?

Precisely 210 × 297 mm. At 300 DPI, export at 2480 × 3508 px for sharp dieline prints.

How A4 Paper Fits Into Dieline Creation?

When you build a dieline in Illustrator, A4 acts like your test canvas — a controlled environment where you can visualise size, closure, and design alignment.

Here’s the process most pros follow:

Draw your box or sleeve outline on an A4 artboard.
Add cut (solid) and fold (dashed) lines.
Print at 100% scale on 80–120 gsm paper.
Score lightly and assemble the mockup.
Adjust panel sizes or flaps before finalising the production version.

This small-scale prototype saves time and money. It’s easier to test fit on A4 than waste a full sheet of boxboard.

When to Go Beyond A4?

Of course, not every product fits neatly onto A4. Once you start designing for mailers, rigid presentation boxes, or multi-item kits, you’ll need larger sheets — A3, A2, or custom die formats.

If your prototype needs more room:

Move to A3 (297 × 420 mm) for mid-size boxes or folded cartons.
Use A2 or SRA3 for packaging with deep sides or inserts.
Ask your printer for custom dieline layouts that optimise material usage.

🔎 PAA Answer

Is A5 bigger than A4 paper size?

No. A5 is half of A4 (148 × 210 mm). For bigger prototypes move up to A3 or beyond.

A4 Paper Setup for Printing Templates

Before you print your next dieline test, check these setup details:

Add 3 mm bleed and 3–5 mm safe zone.
Use CMYK colour mode for print accuracy.
Set resolution to 300 DPI minimum.
Include registration marks and fold guides for assembly.
For mockups, print on 80 gsm to 160 gsm paper — or kraft stock if you want to test a natural look.

These A4-printed dielines aren’t just handy for testing; they make excellent client presentation pieces. Let your client hold and fold something tangible — it builds instant confidence in your design.

Real-World Uses: A4 Box Templates That Work

A4 can handle more than you’d think. Here are some packaging types that fit comfortably on an A4 dieline:

Product Type	Fits on A4?	Best Use Case
Soap Box	✅	Folding carton, easy prototype
Candle Box	✅	Test insert fit & closure style
Cosmetic Jar Box	✅	Small rigid or sleeve design
Mini Mailer Box	✅	Sample kits & subscriptions
Gift Sleeve or Insert	✅	Structural presentation wrap