How to convert a us letter pdf to a4 paper size
- Step 1Drop the US Letter PDF onto the tool — Open PDF Resize and drag the file in. Free tier handles up to 2 MB / 50 pages; Pro up to 50 MB / 500 pages. The file is read in-browser; nothing uploads.
- Step 2Click the A4 preset — Three preset buttons sit above the size fields: A4, Letter, Legal. Click A4 — it sets Width 595, Height 842. (To go the other direction, A4→Letter, click Letter for 612 × 792 instead.)
- Step 3Verify the target reads 595 × 842 — The Width (pt) and Height (pt) fields update to the A4 values. There is no inch/mm selector — these are PostScript points. 595 × 842 pt is exactly A4.
- Step 4Run the conversion — Process the file. Each Letter page is scaled to fit A4's width and centred. Expect a thin white band above and below the content because A4 is proportionally taller than Letter.
- Step 5Compare a page against the original — Open the output beside the source. The content should look ~3% smaller, perfectly centred, with no clipped edges. The page count is unchanged.
- Step 6Download and print on A4 — Save the A4 PDF. In the print dialog choose 'Actual size' / 100% so the driver doesn't re-scale your already-correct A4 page.
Letter vs A4 — the numbers that matter
The two formats differ on both axes. The tool fields are in points; mm/inch shown for reference only.
| Format | Points (tool input) | Millimetres | Inches | Aspect ratio |
|---|---|---|---|---|
| US Letter | 612 × 792 | 215.9 × 279.4 | 8.5 × 11 | 0.773 : 1 |
| A4 | 595 × 842 | 210 × 297 | 8.27 × 11.69 | 0.707 : 1 |
| Difference | −17 wide, +50 tall | −5.9 mm / +17.6 mm | −0.23 in / +0.69 in | A4 is narrower & taller |
What the Letter→A4 conversion produces
Because A4 is narrower than Letter, width is the binding constraint, so content scales down slightly and gains a top/bottom border.
| Step | What happens to a Letter page |
|---|---|
| 1. New A4 page created | A blank 595 × 842 pt page is added to a fresh document |
| 2. Scale computed | scaleX = 595/612 = 0.972, scaleY = 842/792 = 1.063; the tool uses min → 0.972 |
| 3. Content scaled | Letter content drawn at 97.2% of original size — proportional, no distortion |
| 4. Centred | Horizontally edge-to-edge (width fills); vertically centred with a white band top and bottom |
| 5. Repeat for every page | All pages converted to A4; page count unchanged |
Cookbook
Real Letter↔A4 conversions and exactly what comes out.
Standard Letter contract to A4
A signed contract drafted in a US word processor, needed on A4 for a European filing. One preset click does it.
Input: contract.pdf, 8 pages, all 612 x 792 pt (Letter)
Action: click 'A4' preset -> Width 595, Height 842
Output: 8 pages, all 595 x 842 pt (A4)
content at 97.2% size, full width,
~25 pt white band top + bottomA4 back to Letter for a US recipient
The reverse trip. A European A4 document a US office wants on Letter. Here A4 is taller, so height is the limit and a left/right border appears.
Input: invoice.pdf, 3 pages, 595 x 842 pt (A4)
Action: click 'Letter' preset -> Width 612, Height 792
scaleX = 612/595 = 1.029, scaleY = 792/842 = 0.941
min -> 0.941, content drawn at 94.1%
Output: 3 pages, 612 x 792 pt (Letter)
full height, thin white band left + rightWhy footers stop getting clipped
The whole reason to convert rather than rely on the printer. A driver's shrink-to-fit re-scales the page non-uniformly relative to A4's printable area; an explicit conversion makes the page genuinely A4.
Before (Letter PDF on A4 printer, driver 'fit'): page rescaled to A4 printable area, footer 'Page 1 of 8' clipped by 2 mm After (converted to A4, print at 100%): page already A4 -> driver does nothing, footer prints in full
Letter deck where margins must stay generous
If the 3% shrink loses too much, you can keep content at 100% by NOT converting and instead just verifying the printer uses A4 stock — but if A4 page boxes are mandatory, conversion is the trade-off.
Letter content scaled to A4 width = 97.2% of original => 0.5 in (36 pt) margin becomes ~0.486 in (35 pt) If that margin loss is unacceptable, the source must be re-laid-out for A4 in the authoring app. Resize cannot reflow text; it only scales the page as a whole.
Letter PDF with a fillable form
Conversion flattens interactive content. Fill the form, flatten, then convert.
Input: w9_letter.pdf (Letter, AcroForm fields) Wrong: convert to A4 first -> fields vanish Right: 1. fill the fields in a PDF reader 2. PDF Flatten 3. convert to A4 -> answers preserved as page content
Edge cases and what actually happens
Converted text looks slightly smaller
ExpectedLetter→A4 scales content to ~97.2% because A4 is narrower. The shrink is under 3% and imperceptible in normal body text. If your layout has no margin to spare, that's a layout problem the resize tool can't solve — it scales the page, it doesn't reflow text.
A4→Letter direction borders the sides, not top/bottom
By designGoing A4→Letter, A4 is the taller shape, so height binds and content scales to ~94%, full height, with white bands left and right. This is the mirror of the Letter→A4 case and is correct proportional behaviour.
Form fields gone after conversion
FlattenedEach page is rebuilt by embedding the original as a graphic (embedPages), which drops AcroForm fields, buttons, and JavaScript. Fill and flatten the form before converting.
Hyperlinks and bookmarks lost
Not preservedLink annotations and the outline tree are not reproduced onto the new pages. After conversion, clickable links and bookmarks are gone. If links matter more than the page box, leave the file as Letter and set the printer to A4 stock instead.
Mixed Letter and A4 pages in one file
HandledThe tool resizes every page to the chosen target regardless of its starting size. Already-A4 pages get scale 1.0; Letter pages get scaled. The result is uniformly the target size — which is exactly what you want for a clean cross-region document.
Free tier file over 2 MB / 50 pages
Tier limitFree PDF processing caps at 2 MB and 50 pages. A scanned Letter document can exceed 2 MB. Compress with PDF Compress (Aggressive) or upgrade to Pro (50 MB / 500 pages).
Landscape Letter page
By designA landscape Letter page (792 × 612 pt) converted to A4 portrait scales to the narrow width and leaves big top/bottom borders. Rotate it with PDF Rotate first, or convert to A4 landscape by typing 842 × 595 manually.
Encrypted Letter PDF
HandledThe engine loads with ignoreEncryption: true, so owner-password restrictions don't block conversion. A PDF needing a password to open must first go through PDF Unlock.
You expected the page to fill A4 edge-to-edge
ExpectedLetter and A4 have different aspect ratios (0.773 vs 0.707), so a converted page can never fill A4 on both axes without distortion. The unavoidable white band on one pair of edges is the cost of keeping proportions correct. There is no crop-to-fill mode.
Page count changed
Cannot happenConversion is one page in, one page out. The output page count always equals the input. To add or remove pages, use PDF Merge or PDF Delete Pages separately.
Frequently asked questions
Will the text look smaller after converting Letter to A4?
Marginally. A4 is narrower than Letter, so content scales to about 97% of original size — under a 3% reduction that's imperceptible in body text. Going the other way (A4→Letter) scales to about 94%.
Can I convert A4 to Letter instead?
Yes. Click the Letter preset (612 × 792 pt) instead of A4 and the same engine scales your A4 content proportionally onto Letter pages. The white border appears on the left and right edges in that direction.
Does converting affect embedded fonts?
No. Fonts stay embedded and text stays vector, so it renders crisply at the new scale and remains selectable (if it was real text in the source). Page-size scaling doesn't touch font data.
Why is there a white border after conversion?
Letter and A4 have different proportions, so fitting one inside the other without stretching always leaves spare space on one pair of edges. The tool fills that space with white and centres your content. It's the correct, distortion-free result.
Can I enter the size in inches?
No — the fields are points only, and the presets fill them in for you. A4 is 595 × 842 pt, Letter is 612 × 792 pt. If you ever need a custom size, convert your inches to points by multiplying by 72.
Can I convert only certain pages from Letter to A4?
No. The conversion applies to all pages. If you need only some pages at A4, extract them with PDF Extract Pages, convert, and recombine with PDF Merge.
Will it reflow my text to A4's taller page?
No. Resize scales the page as a single unit — it does not re-wrap paragraphs or move content to fill A4's extra height. To genuinely re-flow for A4 you must re-export from the authoring app (Word, InDesign, etc.) with A4 set as the page size.
My form fields disappeared after converting — why?
The conversion embeds each page as a flattened graphic, which removes interactive form fields, links, and annotations. Fill and flatten the form first, then convert.
How large a Letter PDF can I convert?
Free: 2 MB and 50 pages. Pro: 50 MB and 500 pages. pro_media: 500 MB. Compress oversized scans first with PDF Compress (Aggressive).
Is anything uploaded to a server?
No. The conversion runs in-browser via pdf-lib; the file never leaves your device. Only an anonymous file-processed counter is recorded for dashboard stats, with no content.
After converting to A4 it still prints with margins off — what now?
Set the print dialog to 'Actual size' / 100%. A correctly-converted A4 PDF prints true only if the driver isn't re-scaling it via a 'fit to page' setting, which is the most common remaining cause.
Is converting better than just changing the printer to A4 paper?
It depends. If the recipient prints, telling them to load A4 and print at 100% avoids the ~3% shrink and keeps links/forms intact. But if the file itself must be A4 (archival systems, fixed-size submission portals), convert — that's the only way to change the actual page box.
Privacy first
All PDF processing runs locally in your browser using PDF-lib and pdf.js. No file is ever uploaded — only metadata counters are saved for signed-in dashboard stats.