For documents
Resumes, reports, forms, manuals and business documents rely on standard sizes so they print correctly and look professional.
Paper Sizes Explained Clearly
The ultimate paper size guide for documents, notebooks, envelopes, posters and PDFs
Choosing the correct paper size is important for printing quality, layout balance, printer compatibility, mailing, publishing, notebook design, PDF export, and professional presentation. Whether you are working with A4, A5, B5, Letter, Legal, ANSI, ARCH or envelope sizes, this guide helps you understand what each size is and when to use it.
A, B and C series explained
A4 vs Letter made simple
A5 vs B5 notebook guide
DPI and print tips included
At a glance
The ISO system is built so each size is based on halving the previous one. That means A4 is half of A3, A5 is half of A4, and so on. This makes resizing predictable and practical for printing and copying.
What paper size means and why it matters
A paper size is the width and height of a sheet. That sounds simple, but the size you choose changes how content looks, how printers handle it, how it fits envelopes and folders, and how comfortable it feels to read or write on.
For planners and books
A5 and B5 are especially popular because they balance portability and writing space in different ways.
For print efficiency
Choosing the right size from the beginning reduces scaling issues, margin problems, trimming mistakes and wasted paper.
Main paper size standards you should know
Visual: ISO families
Simple rule of thumb
- A series — office documents, books, study material
- B series — notebooks, posters, extra writing space
- C series — envelopes matched to A sizes
- Letter / Legal — US office printing
- ANSI / ARCH — engineering and architecture
ISO international standard
The ISO family includes A series, B series and C series. It is the most common system worldwide and is used for office printing, publishing and stationery.
A-series sizes are based on halving the previous sheet. That is why A4, A5 and A6 are so easy to scale between.
How the families relate
A sizes are for documents, B sizes usually offer more space than A sizes, and C sizes are designed mainly for envelopes that match A sheets.
Example: A4 fits in C4 without folding, and folded A4 fits well in C5.
North American standards
Letter, Legal, Tabloid and Executive are widely used in the United States and parts of North America. Technical work also often uses ANSI and ARCH sizes.
If your audience is global, it is smart to offer both A4 and Letter export options.
A, B and C series explained clearly
A Series
This is the most familiar family for everyday work. A4 is the standard office page in most countries. A5 is popular for planners and booklets. A3 is great for menus, foldouts and larger layouts.
Best for everyday documentsB Series
B sizes sit between A sizes and are often chosen when users want more space than A sizes offer. B5 is a common notebook and workbook size because it feels roomy without becoming bulky.
Best for notebooks and postersC Series
C sizes are mainly envelope sizes. They are designed so that A-series sheets fit inside logically. For example, A4 fits in C4 without folding, and A5 fits neatly in C5.
Best for envelope matchingMost useful paper size charts
These quick-reference tables cover the paper sizes users most often need for documents, PDF export, design and printing.
ISO A Series
| Size | Millimeters | Inches | 72 DPI | 96 DPI | 150 DPI | 300 DPI |
|---|---|---|---|---|---|---|
| A0 | 841 × 1189 mm | 33.1102 × 46.811 in | 2384 × 3370 px | 3179 × 4494 px | 4967 × 7022 px | 9933 × 14043 px |
| A1 | 594 × 841 mm | 23.3858 × 33.1102 in | 1684 × 2384 px | 2245 × 3179 px | 3508 × 4967 px | 7016 × 9933 px |
| A2 | 420 × 594 mm | 16.5354 × 23.3858 in | 1191 × 1684 px | 1587 × 2245 px | 2480 × 3508 px | 4961 × 7016 px |
| A3 | 297 × 420 mm | 11.6929 × 16.5354 in | 842 × 1191 px | 1123 × 1587 px | 1754 × 2480 px | 3508 × 4961 px |
| A4 | 210 × 297 mm | 8.2677 × 11.6929 in | 595 × 842 px | 794 × 1123 px | 1240 × 1754 px | 2480 × 3508 px |
| A5 | 148 × 210 mm | 5.8268 × 8.2677 in | 420 × 595 px | 559 × 794 px | 874 × 1240 px | 1748 × 2480 px |
| A6 | 105 × 148 mm | 4.1339 × 5.8268 in | 298 × 420 px | 397 × 559 px | 620 × 874 px | 1240 × 1748 px |
ISO B Series
| Size | Millimeters | Inches | 300 DPI |
|---|---|---|---|
| B0 | 1000 × 1414 mm | 39.3701 × 55.6693 in | 11811 × 16701 px |
| B1 | 707 × 1000 mm | 27.8346 × 39.3701 in | 8350 × 11811 px |
| B2 | 500 × 707 mm | 19.685 × 27.8346 in | 5906 × 8350 px |
| B3 | 353 × 500 mm | 13.8976 × 19.685 in | 4169 × 5906 px |
| B4 | 250 × 353 mm | 9.8425 × 13.8976 in | 2953 × 4169 px |
| B5 | 176 × 250 mm | 6.9291 × 9.8425 in | 2079 × 2953 px |
| B6 | 125 × 176 mm | 4.9213 × 6.9291 in | 1476 × 2079 px |
ISO C Series envelope sizes
| Size | Millimeters | Inches | Common fit |
|---|---|---|---|
| C4 | 229 × 324 mm | 9.0157 × 12.7559 in | A4 without folding |
| C5 | 162 × 229 mm | 6.378 × 9.0157 in | A5 or folded A4 |
| C6 | 114 × 162 mm | 4.4882 × 6.378 in | A6 cards and notes |
| C7 | 81 × 114 mm | 3.189 × 4.4882 in | Small inserts and cards |
US office sizes
| Size | Inches | Millimeters | 300 DPI |
|---|---|---|---|
| Letter | 8.5 × 11 | 215.9 × 279.4 mm | 2550 × 3300 px |
| Legal | 8.5 × 14 | 215.9 × 355.6 mm | 2550 × 4200 px |
| Tabloid | 11 × 17 | 279.4 × 431.8 mm | 3300 × 5100 px |
| Executive | 7.25 × 10.5 | 184.15 × 266.7 mm | 2175 × 3150 px |
ANSI and ARCH quick view
| Size | Inches | Typical use |
|---|---|---|
| ANSI A | 8.5 × 11 | General technical documents |
| ANSI B | 11 × 17 | Larger layouts and drawings |
| ANSI C | 17 × 22 | Engineering drawings |
| ARCH A | 9 × 12 | Small architectural sheets |
| ARCH D | 24 × 36 | Construction plans |
| ARCH E | 36 × 48 | Large presentation boards |
Full expandable paper size database
This section includes all 53 paper sizes from the database. Search by name, series, or region, then expand any size to view full measurements, aspect ratio, default orientation, and all DPI pixel values.
Showing 53 sizes
No paper sizes match your search.
The comparisons people ask about most
A4 vs Letter
These two sizes look close, but they are not the same. Letter is slightly wider. A4 is taller.
| Feature | A4 | Letter |
|---|---|---|
| Millimeters | 210 × 297 mm | 215.9 × 279.4 mm |
| Inches | 8.2677 × 11.6929 in | 8.5 × 11 in |
| Main region | International / ISO | US / Canada |
| Practical note | Taller page | Slightly wider page |
A5 vs B5
A5 is more portable and compact. B5 gives noticeably more writing space and often feels better for study notes and workbooks.
| Feature | A5 | B5 |
|---|---|---|
| Millimeters | 148 × 210 mm | 176 × 250 mm |
| Inches | 5.8268 × 8.2677 in | 6.9291 × 9.8425 in |
| Portability | Higher | Moderate |
| Writing space | Compact | More spacious |
Legal vs Letter
This is a very common office question in North America. Legal keeps the same width as Letter but adds more height.
| Feature | Letter | Legal |
|---|---|---|
| Inches | 8.5 × 11 in | 8.5 × 14 in |
| Millimeters | 215.9 × 279.4 mm | 215.9 × 355.6 mm |
| Use | General office documents | Contracts, legal forms, long forms |
| Main difference | Standard length | Much taller page |
A3 vs Tabloid
These are often compared for posters, booklets, menus, and folded print work. They are close in size, but not identical.
| Feature | A3 | Tabloid |
|---|---|---|
| Millimeters | 297 × 420 mm | 279.4 × 431.8 mm |
| Inches | 11.6929 × 16.5354 in | 11 × 17 in |
| Main region | International / ISO | North America |
| Typical use | Posters, brochures, layouts | Large office prints, newsletters |
C4 vs C5 envelope
Many users search this when mailing documents. The choice depends on whether the A4 page stays flat or gets folded.
| Feature | C4 | C5 |
|---|---|---|
| Millimeters | 229 × 324 mm | 162 × 229 mm |
| Best for | A4 without folding | A5 or folded A4 |
| Use case | Formal mailing, flat documents | Regular office mail |
| Space | Larger | More compact |
ANSI A vs Letter
This one confuses many users. ANSI A and Letter are effectively the same physical size in common usage.
| Feature | ANSI A | Letter |
|---|---|---|
| Inches | 8.5 × 11 in | 8.5 × 11 in |
| Millimeters | 215.9 × 279.4 mm | 215.9 × 279.4 mm |
| Main use | Engineering / technical naming | Office / general naming |
| Difference | Naming convention | Naming convention |
Visual: A4 vs Letter
Visual: A4 inside C4 envelope
Printing and design advice
For office documents
Use A4 for international audiences and Letter for US-focused workflows. Always keep safe margins because home and office printers often cannot print edge to edge.
For planners and journals
Choose A5 when portability matters. Choose B5 when users need more space to write or when the notebook should feel less cramped.
For posters and drawings
A3, B3, ANSI B, ANSI C, ARCH D and ARCH E are common stepping stones for visual layouts, technical sheets and large-format planning.
Recommended DPI guide
| DPI | Best for | Result |
|---|---|---|
| 72 DPI | Basic screen preview | Lightweight, not ideal for print |
| 96 DPI | Web display and browsers | Common digital reference size |
| 150 DPI | Draft printouts | Decent for low-detail printing |
| 300 DPI | Standard print-ready work | Best general print choice |
| 600 DPI | Fine detail and premium output | Sharper but larger file size |
Quick print checklist
- Confirm whether the job is ISO or North American
- Use millimeters or inches when approving custom jobs
- Export the PDF in the final target size from the start
- Use 300 DPI for most print-ready content
- Check bleed, trim and safe area for design work
- Do not treat A4 and Letter as identical
When to use which paper size
| Use case | Recommended size | Reason |
|---|---|---|
| Resume, formal letter, report | A4 or Letter | Standard office compatibility |
| Notebook or workbook | B5 | Better writing space |
| Journal or planner | A5 | Portable and compact |
| Brochure or foldout sheet | A3 | Larger layout area |
| A4 document envelope | C4 | Fits without folding |
| Long legal forms | Legal | More vertical space |
| Architecture and plans | ARCH D / ARCH E | Common industry format |
Frequently asked questions
Is A4 the same as Letter size?
No. A4 is 210 × 297 mm, while Letter is 215.9 × 279.4 mm. Letter is slightly wider, but A4 is taller.
Which is bigger: A5 or B5?
B5 is bigger than A5. It gives more room for writing and layout, while A5 is easier to carry and store.
Which envelope should I use for A4 paper?
Use C4 if you want the A4 sheet to remain flat. Use C5 if you are folding the A4 sheet in half.
What DPI should I use for print-ready PDF files?
300 DPI is the standard safe choice for most high-quality printing. Use 600 DPI for finer detail when file size is not a concern.
Which paper size is best for a planner or journal?
A5 is excellent for portability. B5 is better when the user wants more writing space and a roomier page feel.
Conclusion
Once you understand A4, A5, B5, Letter, Legal, C4 and C5, you can handle most paper, PDF and printing decisions with confidence. The right size improves readability, print quality, portability and professional presentation.