A paper sizes offline chart is a browser-based reference that loads every standard sheet dimension and a DPI-to-pixels converter directly into your browser, so once the page is open you can look up sizes, convert units, and compute pixel dimensions without any internet connection. Because the reference table and converter both run locally using JavaScript, nothing is uploaded to a server, no account is required, and the page continues to work in airplane mode or on a metered connection as long as your browser tab stays alive. That setup makes it practical for designers working from a café with patchy Wi-Fi, students preparing a poster in a classroom without network access, and developers who want a reliable size lookup while testing offline-first apps. The chart stores the ISO 216 dimensions for the A and B series and the ANSI/US sizes for Letter, Legal, and Tabloid locally, so every value you see was already on the page before you went offline. For anyone who keeps reaching for a paper size ruler or a memorised cheat sheet, an offline tool turns the browser tab itself into that cheat sheet. The Paper Sizes Chart follows this model, keeping every calculation on your device.
What "Paper Sizes Offline" Actually Means
An offline paper size chart is not a downloadable PDF or a printed poster — it is a web page whose logic, data, and converter all execute inside your browser. Once the page has fully loaded the first time you visit it, your browser keeps the HTML, CSS, and JavaScript in memory. As long as you do not close the tab, you can disconnect from the internet, refresh nothing, and still look up dimensions, switch units, and run DPI conversions. The math itself is simple enough to ship in a few lines of code: 1 inch equals exactly 25.4 mm, so the converter computes width and height in inches (mm ÷ 25.4), multiplies by the DPI you type in, and rounds to the nearest whole pixel.
For people who work on planes, trains, or in studios with strict no-internet rules, that local-first behaviour matters. There is no upload step, so a confidential layout for an unreleased product never leaves the device. There is no sign-in, so opening the chart on a borrowed laptop takes a single click. There is also no third-party tracker, which is why security-conscious teams sometimes prefer browser-resident tools over cloud apps for routine lookups. Because the tool runs locally, you can also use it on a desktop or a tablet that is connected only to a guest network, or in a workshop where the Wi-Fi is reserved for the cutting plotter.
The Reference Table: Every Standard Sheet in One Place
The offline chart pairs a complete reference table with a live converter. The table covers the international A series (A0 through A10), the B series (B0 through B10), and the North American US group (Letter, Legal, and Tabloid, also called Ledger). Every row shows three unit columns: millimetres, centimetres, and inches, so you can copy whichever your workflow expects without opening a calculator. A selection of the most common sizes is shown below.
| Paper size | Millimetres (mm) | Centimetres (cm) | Inches (in) |
|---|---|---|---|
| A4 | 210 × 297 | 21.0 × 29.7 | 8.27 × 11.69 |
| A3 | 297 × 420 | 29.7 × 42.0 | 11.69 × 16.54 |
| A5 | 148 × 210 | 14.8 × 21.0 | 5.83 × 8.27 |
| US Letter | 215.9 × 279.4 | 21.59 × 27.94 | 8.5 × 11 |
| US Legal | 215.9 × 355.6 | 21.59 × 35.56 | 8.5 × 14 |
| Tabloid (Ledger) | 279.4 × 431.8 | 27.94 × 43.18 | 11 × 17 |
The international standard behind these rows is ISO 216. Its defining trick is the aspect ratio: every sheet has a height-to-width ratio of the square root of two, roughly 1.414. Because of that ratio, folding a sheet in half across its longer side produces two sheets of the next size down, each keeping the same proportions. The series is anchored by A0, which has an area of almost exactly one square metre and measures 841 × 1189 mm. Halving A0 gives A1 (594 × 841 mm), then A2, A3, and the everyday A4 at 210 × 297 mm, continuing all the way down to A10 at 26 × 37 mm. The B series sits between the A sizes and is used for posters, books, and envelopes when an in-between dimension is needed.
North America uses ANSI and US conventions instead, which is why the millimetre values for Letter, Legal, and Tabloid are not round numbers. US Letter is 8.5 × 11 inches (215.9 × 279.4 mm), US Legal is 8.5 × 14 inches (215.9 × 355.6 mm), and Tabloid is 11 × 17 inches (279.4 × 431.8 mm). Because the inch is the anchor unit, the millimetre values are exact conversions rather than rounded ones, which is also why Letter and A4 are close in size but never identical: A4 is a little narrower and a little taller.
Pixel Conversion at Any DPI, Computed Locally
A physical sheet of paper has no fixed pixel count until you choose a resolution. DPI, dots per inch, bridges the physical and digital worlds: the pixel width equals the width in inches multiplied by the DPI, rounded to a whole pixel. The offline converter runs that arithmetic on every keystroke, so the result updates as soon as you finish typing. That makes the same chart useful whether your project is heading to a print queue, a slide deck, or a website thumbnail.
Print and screen use very different DPI values, which is why a live converter beats a static chart. At 300 DPI, the standard for high-quality print, A4 becomes 2480 × 3508 pixels. At 72 DPI, a classic screen value tied to early Mac displays, the same A4 is only about 595 × 842 pixels. At 150 DPI, a middle ground often used for office documents and slide decks, A4 works out to roughly 1240 × 1754 pixels. Designers set canvas sizes in pixels but think in paper sizes, and a print shop asks for 300 DPI artwork because the dots need to be small enough to look smooth on paper.
The single worked example for A4 at 300 DPI uses the formula millimetres ÷ 25.4 × DPI, rounded to the nearest whole pixel:
- Width: 210 mm ÷ 25.4 × 300 = 8.2677 × 300 ≈ 2480 px
- Height: 297 mm ÷ 25.4 × 300 = 11.6929 × 300 ≈ 3508 px
That matches the 2480 × 3508 figure widely accepted as A4 at print resolution. Other sizes follow the same path — the converter handles B series, US Letter, Legal, and Tabloid with the same arithmetic, and the live result means you do not have to redo the math by hand when you change the DPI. For any other value, type a different DPI into the field and the pixel dimensions recompute on the spot.
How to Use the Chart Without an Internet Connection
- Open the Paper Sizes Chart in your browser tab so the page loads fully — the reference table and converter need to be in memory before you go offline.
- Scan the reference table to find your paper size in the A series, B series, or US group, with dimensions shown in millimetres, centimetres, and inches.
- In the converter, choose a paper size from the dropdown to load its exact dimensions.
- Type the resolution you need in the DPI field — 300 is standard for print, 72 for screen — to see the pixel width and height update instantly.
- Read off the pixel result alongside the millimetre, centimetre, and inch values to set up your canvas or export.
- Keep the tab open so the chart stays available even after your device drops the network. For one-tap access, add the page to your bookmarks bar or use your browser's "install as app" option on supported platforms.
Standard Sizes Worth Saving to Your Bookmarks
A few sizes come up so often that they are worth committing to muscle memory, or at least bookmarking for fast lookup. A4 (210 × 297 mm) is the everyday sheet for letters, reports, and résumés across most of the world, and it is the page size most printers default to outside North America. A3 (297 × 420 mm) is twice the area of A4 and the standard for mid-size posters, folded brochures, and architectural plans. A5 (148 × 210 mm) is a popular size for flyers, greeting cards, and small booklets.
US Letter (8.5 × 11 in) is the North American default for the same jobs A4 handles elsewhere. US Legal (8.5 × 14 in) adds three inches of height and is the standard for legal pads and some contracts. Tabloid (11 × 17 in), also called Ledger, is the smallest of the engineering and newspaper sizes and is often used for spreadsheets and small diagrams. B4 (250 × 353 mm) and B5 (176 × 250 mm) fill the gaps when a size between A and US would be ideal, which is why B5 is a favourite for paperback novels in Europe and Japan.
For an offline workflow, the most useful habit is to set the DPI once per project and reuse it. A poster heading to a professional printer almost always wants 300 DPI; a slide deck for screen sharing can stay at 96 or 150 DPI; web images are usually 72 DPI unless the design specifies otherwise. Keeping those three numbers in mind, alongside the three or four sizes you reach for most, turns the chart from a lookup you visit into a reference you barely need. Because everything is local, you can also script the workflow around it — for instance, building a printable layout, exporting an image at the right pixel dimensions, and confirming the result against the same offline chart once the file is finished.
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