Every standard paper size in the A series, B series, and US group can be looked up in one reference table that shows dimensions in millimetres, centimetres, inches, and pixels, so you can match the correct sheet to every file before batching a print or export job. When you prepare multiple files at once, each one can demand a different sheet size: a poster in A1, a handout in A4, a US Letter report, and a Tabloid spread. Sorting those sizes on the fly is where errors creep in, because A4 and US Letter are close but not interchangeable (A4 is 210 by 297 mm, US Letter is 215.9 by 279.4 mm), and the pixel count for any physical sheet depends entirely on the DPI you choose. A live paper size chart puts every standard dimension side by side and converts it to pixels at the resolution you type, so you can run through a whole batch of files with consistent numbers. The conversion math is fixed: one inch equals exactly 25.4 mm, so millimetres to inches is a division by 25.4, and pixels equal the dimension in inches multiplied by the DPI, rounded to a whole pixel.
Why a Chart Matters Before You Touch Multiple Files
Most batch problems start with an assumption. A designer assumes every PDF in a folder is A4, the printer assumes Letter, and the binder assumes Legal. None of those assumptions hold when a folder mixes invoices, posters, and reports. Looking up sizes for each file takes a few seconds per file when you have a complete chart in front of you, and it prevents the much slower troubleshooting that follows a misprint or a clipped export.
A paper size chart also lets you set the pixel canvas for every file before you open the design software. That matters because the pixel count is not a property of the paper, it is a property of the resolution you choose. A4 at 300 DPI (the print standard) is 2480 by 3508 pixels; the same A4 at 72 DPI (the screen standard) is about 595 by 842 pixels. If your batch mixes print-ready and screen-only files, you need both numbers, and you need them fast.
For files that need to land on a single page together, you can also turn to Paper Sizes Chart to confirm the target sheet before you merge, lay out, or resize. Once you know the size of each input file and the size of the output sheet, the rest of the workflow stays predictable.
Standard Paper Sizes Side by Side
The table below lists the most common sizes across the three groups, with dimensions in millimetres and inches. Values come from ISO 216 for the A and B series and from ANSI and US conventions for Letter, Legal, and Tabloid.
| Series / Standard | Size | Width × Height (mm) | Width × Height (in) |
|---|---|---|---|
| A series (ISO 216) | A0 | 841 × 1189 | 33.11 × 46.81 |
| A series (ISO 216) | A1 | 594 × 841 | 23.39 × 33.11 |
| A series (ISO 216) | A2 | 420 × 594 | 16.54 × 23.39 |
| A series (ISO 216) | A3 | 297 × 420 | 11.69 × 16.54 |
| A series (ISO 216) | A4 | 210 × 297 | 8.27 × 11.69 |
| A series (ISO 216) | A5 | 148 × 210 | 5.83 × 8.27 |
| B series (ISO 216) | B0 | 1000 × 1414 | 39.37 × 55.67 |
| B series (ISO 216) | B1 | 707 × 1000 | 27.83 × 39.37 |
| B series (ISO 216) | B2 | 500 × 707 | 19.69 × 27.83 |
| ANSI / US | US Letter | 215.9 × 279.4 | 8.5 × 11 |
| ANSI / US | US Legal | 215.9 × 355.6 | 8.5 × 14 |
| ANSI / US | Tabloid / Ledger | 279.4 × 431.8 | 11 × 17 |
One detail to notice in the table: every A and B size keeps a height-to-width ratio equal to the square root of two (about 1.414). That is why folding A0 in half across its longer side gives A1, A1 folds to A2, and so on. The US sizes do not follow that rule, which is why A4 and Letter never line up perfectly even though they look similar at a glance.
How to Look Up Sizes for Several Files at Once
The fastest way to handle a folder of mixed files is to work through each one against the same reference chart and the same converter. The steps below assume you are using the Paper Sizes Chart in your browser.
- Scan the reference table on the chart to find each file's paper size in the A series, B series, or US group, and read the dimensions in millimetres, centimetres, or inches.
- In the converter, choose that paper size from the dropdown so its exact dimensions load into the converter fields.
- Type the resolution you need in the DPI field. Type 300 for print-quality artwork, 150 for draft prints, and 72 for screen previews, and watch the pixel width and height update as you change the number.
- Read off the pixel result alongside the millimetre, centimetre, and inch values, and record or copy the numbers for that file before moving to the next.
- Repeat the dropdown and DPI steps for every file in the batch so each one has its own set of dimensions written down.
- Use the recorded numbers to set up your canvas, your export settings, or your print queue so every file in the batch uses its correct size.
The whole loop for one file takes a few seconds, and the dropdown plus DPI field makes it easy to switch between sizes without losing your place. If you want a deeper walkthrough of how the converter behaves at different DPIs, the Paper Size Chart in Pixels for Any DPI and Paper Format guide covers the same mechanics in more detail.
Converting Each File's Size to Pixels
Once you have the physical dimension, the pixel conversion follows one rule: pixels equal the width or height in inches multiplied by the DPI, then rounded to the nearest whole pixel. Worked example for A4 at 300 DPI:
- Width in inches: 210 mm ÷ 25.4 = 8.2677 in
- Width in pixels: 8.2677 × 300 = 2480 pixels (rounded)
- Height in inches: 297 mm ÷ 25.4 = 11.6929 in
- Height in pixels: 11.6929 × 300 = 3508 pixels (rounded)
That gives A4 at 300 DPI as 2480 by 3508 pixels. The same A4 at 150 DPI drops to roughly 1240 by 1754 pixels, and at 72 DPI it drops again to roughly 595 by 842 pixels. For a batch of print files, run all of them at 300 DPI; for a batch of screen previews, 72 DPI is enough.
Common Size Mix-Ups in Multi-File Jobs
The errors below appear over and over in folders that hold several files at once, and each one is easy to prevent with a quick chart check.
- A4 treated as Letter. A4 is 210 by 297 mm and Letter is 215.9 by 279.4 mm, so A4 is narrower and taller. A document formatted for one shifts margins or clips when printed on the other.
- Legal mistaken for Letter. Both share an 8.5 inch width, but Legal is 14 inches tall instead of 11. A file assumed to be Letter will print with a wide bottom margin on Legal paper.
- Tabloid confused with A3. Tabloid is 11 by 17 inches and A3 is 297 by 420 mm (about 11.69 by 16.54 inches). They are close in area but not the same shape, so a Tabloid layout can run off the edge of A3 paper.
- Wrong DPI picked for the job. A poster laid out at 72 DPI looks fine on screen but turns soft when sent to a print shop that expects 300 DPI. The chart shows both numbers so the choice is explicit.
- Pixel size treated as fixed. A4 is not "2480 by 3508" in absolute terms. That is A4 at 300 DPI. The pixel size moves up and down with the resolution you choose.
Build a Workflow That Stays Consistent
A repeatable batch workflow removes the guesswork. Start by sorting your files by sheet size so every file in a group uses the same target paper. Look up each group's dimensions once, set a single DPI for the whole batch (300 for print, 72 for screen), and record the pixel dimensions next to each file's name. When the same numbers are reused for every file in a group, the export step becomes a copy-paste exercise instead of a fresh calculation.
For mixed-size jobs that have to land on a single output sheet, the same approach applies, but you also need to know the target sheet before you start. Once each input file has its own dimensions recorded and the target sheet is confirmed, the layout work is mechanical. From there, the related tools on the site can handle the actual merging, resizing, or conversion without re-entering the numbers you already collected.
Related reading: N-Up Multiple Pages From One PDF at Once.