Print Guide
Paper Sizes Calculator Guide: A4, Letter, Legal, Tabloid, Photo
Paper sizes shouldn’t feel like a mystery, but they often do. A4 looks close to US Letter, Legal is taller, Tabloid is wider, and photo sizes add another layer of “wait, how big is that?” If you’ve ever opened a printable and wondered why it doesn’t fit, this guide is for you. We’ll keep it simple, show the sizes that actually matter, and give you an easy way to convert between inches and millimetres.
If you want the quick answer, the Paper Sizes Calculator gives you exact dimensions in seconds. But if you want to understand the “why,” keep reading.
Quick answer: which paper size should I use?
If you’re printing regular documents, planners, or worksheets, there are two sizes you’ll see over and over: A4 and US Letter. A4 is the standard in most countries. US Letter is the standard in the United States and Canada. If you’re not sure which to pick, check your printer settings or the paper you already have at home. The right choice is usually whatever your printer expects by default.
Need something bigger? Legal is the same width as Letter but taller. Tabloid is wider and used for posters, charts, and bigger layouts. Photo sizes are their own world, usually listed in inches like 4×6 or 8×10.
A4 vs Letter: the classic mix‑up
A4 is 210 × 297 mm (8.27 × 11.69 in). US Letter is 8.5 × 11 in (216 × 279 mm). A4 is a little narrower but taller. That difference is small, but it matters. If you design a printable for A4 and print it on Letter, the top and bottom might get clipped. If you design for Letter and print on A4, you’ll get extra white space.
The best fix is to offer both sizes or build in safe margins so your design still fits. It saves you support emails and saves your users from wasted paper.
Common paper sizes (and what they’re for)
A4 (210 × 297 mm)
Standard for documents worldwide. Great for planners, worksheets, and printable tools.
US Letter (8.5 × 11 in)
Standard in the US and Canada. Most home printers default to this size.
Legal (8.5 × 14 in)
Taller than Letter. Good for contracts, long lists, or extra‑long worksheets.
Tabloid (11 × 17 in)
Wider format for posters, classroom charts, and big layouts.
Inches vs millimetres: why conversions matter
A‑series sizes are defined in millimetres. US sizes are defined in inches. If you mix them up or round too aggressively, you can accidentally shift margins or crop a design. That’s why a simple conversion tool is so useful.
Here’s the only number you need to remember: 1 inch = 25.4 mm. Divide mm by 25.4 to get inches, or multiply inches by 25.4 to get mm. The Paper Sizes Calculator does this instantly.
Use the calculator (fastest path)
If you’re in a hurry, open the Paper Sizes Calculator and pick the size you need. You’ll see mm and inches side by side, plus a DPI section to calculate the pixel dimensions for print‑ready files.
How DPI connects to paper size
Paper size tells you how large the print will be. DPI tells you how many pixels you need to fill that size with detail. If you already have an image, you can calculate its DPI at a target size. If you’re creating a new file, you can calculate the pixel dimensions you need to hit a target DPI.
Example: A4 is 8.27 × 11.69 inches. At 300 DPI, you need about 2481 × 3508 pixels. That’s why many A4 print files are exported at 2480 × 3508 pixels for crisp results.
Photo print sizes (the short guide)
Photo sizes are usually listed in inches: 4×6, 5×7, 8×10, and 11×14 are the most common. They don’t match A‑series ratios, so you might need to crop if your photo is a different shape. The calculator helps you check the size before you print.
- 4×6: classic photo print size (2:3 ratio)
- 5×7: popular for frames and gifts
- 8×10: common for portraits and display prints
- 11×14 and 12×18: larger wall prints
Legal and Tabloid: when they make sense
Legal paper (8.5 × 14 in) is useful for longer worksheets, contracts, or lists that feel cramped on Letter. Tabloid (11 × 17 in) is a wider format and works well for posters, classroom charts, and bigger layouts.
One quick tip: not all home printers support Tabloid, and some need a special tray for Legal. It’s worth checking your printer specs before you design a full set.
A‑series sizes in plain terms
A‑series sizes follow a simple rule: each size is half of the previous one. A0 is huge, A1 is half, A2 is half of that, and so on. A4 lands in the sweet spot for everyday printing, which is why it became the default in most places.
This makes scaling easy. A5 is half of A4. A3 is double A4. If you build templates around A‑sizes, you can scale up or down without re‑designing everything.
Practical checklist before you print
- Confirm the paper size your printer is set to.
- Match your file size to the paper size (A4 vs Letter).
- Check DPI if you care about sharp text or clean lines.
- Print a single test page before doing a full run.
Related tools for print‑ready work
Summary
Paper sizes don’t have to be confusing. Use the calculator to convert between mm and inches, confirm the right format, and check pixels for print‑ready quality. If you’re unsure, start with A4 or Letter, print a quick test page, and adjust from there.