How to resize pdf pages to a custom width and height
- Step 1Convert your spec into points — The fields take points, not mm or inches. Convert once: from millimetres, mm ÷ 25.4 × 72; from inches, inches × 72. Example: a 120 × 120 mm sleeve = 120 ÷ 25.4 × 72 ≈ 340 × 340 pt.
- Step 2Open the resize tool and drop the PDF — Drag the file into PDF Resize. Free tier: up to 2 MB / 50 pages. Pro: 50 MB / 500 pages. The file is read in-browser; nothing uploads.
- Step 3Ignore the presets, type your size — Skip the A4/Letter/Legal buttons. In Width (pt) and Height (pt) type your custom point values. Each field enforces a minimum of 72 pt.
- Step 4Run the resize — Process. The tool creates a page at your exact size for every page, scales the content proportionally to fit, and centres it. If your target ratio differs from the source, a white border appears on one pair of edges.
- Step 5Verify the output dimensions — Open the result in a viewer that shows page size and confirm it reads your target points. The page count matches the input — resize never adds or removes pages.
- Step 6Download for your specific application — Save the custom-sized PDF for print, e-reader sideloading, or wherever the odd size is required.
Common custom sizes converted to points
The tool takes points only. Convert your spec once and type the point values. Rounded to the nearest point.
| Use case | Dimensions | Points to type (W × H) |
|---|---|---|
| CD/DVD booklet sleeve | 120 × 120 mm | 340 × 340 |
| DL envelope insert | 99 × 210 mm | 281 × 595 |
| Square social (Instagram-style) | 1080 × 1080 px @ 72 DPI | 1080 × 1080 |
| Kindle / 6-inch e-reader | 90 × 120 mm (approx) | 255 × 340 |
| Business card | 85 × 55 mm | 241 × 156 |
| US Half-Letter | 5.5 × 8.5 in | 396 × 612 |
Unit conversions to points
There is no unit picker — these are the formulas to get to points (the only unit the fields accept).
| From | Formula | Worked example |
|---|---|---|
| Millimetres | mm ÷ 25.4 × 72 | 210 mm ÷ 25.4 × 72 = 595 pt |
| Centimetres | cm ÷ 2.54 × 72 | 29.7 cm ÷ 2.54 × 72 = 842 pt |
| Inches | in × 72 | 8.5 in × 72 = 612 pt |
| Pixels @ 72 DPI | px × 1 (1:1) | 1080 px = 1080 pt |
| Pixels @ 300 DPI | px ÷ 300 × 72 | 2480 px ÷ 300 × 72 = 595 pt |
Cookbook
Bespoke custom-size jobs and exactly what to type.
Square page for a social-media PDF
A square target from a portrait source. The portrait content is scaled to fit the square and centred, with white bands left and right.
Spec: square 1080 x 1080 (px @ 72 DPI = pt)
Input: artwork.pdf, 595 x 842 pt (A4 portrait)
Action: Width 1080, Height 1080
scale = min(1080/595, 1080/842) = min(1.815, 1.283) = 1.283
Output: 1080 x 1080 pt, content centred,
white band left + rightCD sleeve from a mm spec
A 120 × 120 mm sleeve. Convert mm to points first, then type.
Spec: 120 x 120 mm
Convert: 120 / 25.4 * 72 = 340.16 -> 340 pt
Action: Width 340, Height 340
Output: 340 x 340 pt page per source page,
content scaled to fit and centredHalf-Letter handout from a Letter source
Shrinking Letter content onto a Half-Letter (5.5 × 8.5 in) page. Same ratio, clean fit.
Spec: 5.5 x 8.5 in -> 396 x 612 pt Input: handout.pdf, 612 x 792 pt (Letter) Action: Width 396, Height 612 scale = min(396/612, 612/792) = min(0.647, 0.773) = 0.647 Output: 396 x 612 pt, content at 64.7%, centred
Below-minimum size gets clamped
A spec smaller than one inch can't be entered — the fields enforce a 72 pt minimum.
Spec wanted: 50 x 50 mm = 142 x 142 pt (OK, above 72) Spec wanted: 20 x 20 mm = 57 x 57 pt (below 72 -> clamped) The field won't accept below 72 pt. For tiny stamps/labels, design at a larger size and let the printer scale down, or keep above 72 pt (1 inch) here.
Custom size with a form you must keep
Resizing flattens interactive fields. Fill and flatten first.
Input: order_form.pdf (with fillable fields) Wrong: resize to custom size -> fields disappear Right: 1. fill the form 2. PDF Flatten 3. resize to your custom points -> answers preserved
Edge cases and what actually happens
Trying to enter the size in mm or inches
Not supportedThere is no unit selector — the Width and Height fields are PostScript points only. Convert your mm/inch spec to points before typing (mm ÷ 25.4 × 72, or inches × 72). The conversion tables above cover the common cases.
Custom size below 72 pt
ClampedEach field enforces a minimum of 72 pt (one inch). A spec under one inch on either axis can't be entered as-is. Design tiny labels at a larger multiple and let the printer scale down, or pick the smallest size at or above 72 pt that preserves your ratio.
Wanting only some pages at the custom size
Not supportedThe custom size applies to every page — there is no page-range field on this tool. Split the pages you want with PDF Extract Pages, resize them to the custom size, then recombine with PDF Merge.
Odd aspect ratio leaves a big white border
ExpectedIf your custom ratio differs a lot from the source (e.g. a square target from a tall portrait), proportional fitting leaves a wide border on one pair of edges. That's correct — there's no stretch-to-fill or crop-to-fill mode. To trim margins instead of padding, use PDF Crop.
Form fields shift or vanish
FlattenedResizing rebuilds each page by embedding the original as a graphic, which drops AcroForm fields entirely (they don't just shift — they're gone). Fill and flatten the form before resizing to a custom size.
Hyperlinks and bookmarks dropped
Not preservedLink annotations and the outline tree aren't reproduced on the new custom pages. After resizing, clickable links and bookmarks are gone. If those matter more than the exact page box, keep the original.
Raster content soft at a larger custom size
ExpectedEnlarging to a bigger custom size interpolates raster images; vector stays crisp. Match your source DPI to the target physical size (px = inches × DPI) so images stay sharp. Resize can't add detail that isn't there.
Free tier limit hit
Tier limitFree PDF processing caps at 2 MB / 50 pages. Compress first with PDF Compress (Lossless) or upgrade to Pro (50 MB / 500 pages).
Encrypted source
HandledThe engine loads with ignoreEncryption: true, so owner-password restrictions don't block resizing. A document that needs a password to open should first go through PDF Unlock.
Output size doesn't match the spec exactly
RoundingPoints are stored as numbers, but a mm→pt conversion rarely lands on a whole point. If you typed 340 for a 120 mm sleeve (true value 340.16 pt), the page is 340 pt — about 0.06 mm short. For tight print specs, round to the nearest point your supplier accepts or supply the spec already in points.
Frequently asked questions
What's the smallest custom page size I can set?
Each field has a 72 pt minimum (one inch), so the smallest is 72 × 72 pt. Anything below is clamped. For sub-inch labels, design at a larger size and let the printer scale down.
Can I enter dimensions in millimetres or inches?
No — the fields are PostScript points only and there's no unit picker. Convert first: mm ÷ 25.4 × 72, or inches × 72. For example, 210 mm = 595 pt and 8.5 in = 612 pt.
Can I resize only some pages to a custom size?
No. The custom size applies to every page in the document — there's no page-range option here. To resize a subset, extract those pages with PDF Extract Pages, resize them, then recombine with PDF Merge.
Will the custom resize affect interactive form fields?
Yes — and more than 'shift'. Resizing embeds each page as a flattened graphic, so AcroForm fields, checkboxes, and buttons are removed entirely. Fill and flatten the form before resizing.
What's the largest custom size?
There's no explicit upper bound on the point value, but practical limits come from the tier file-size cap (free 2 MB, Pro 50 MB) and viewer/printer handling of very large pages. Most large-format work stays well within A2/A1 point dimensions.
Why is there a white border after a custom resize?
When your target ratio differs from the source, proportional fitting (no stretching) leaves spare space on one pair of edges, which the tool fills white and centres content within. To trim margins instead, use PDF Crop.
How do I get the exact points for a pixel design?
At 72 DPI, 1 pixel = 1 point, so a 1080 × 1080 px design is 1080 × 1080 pt. At 300 DPI, divide pixels by 300 and multiply by 72 (px ÷ 300 × 72). The conversion table above lists the formulas.
Does the custom size change my embedded fonts?
No. Fonts stay embedded and text stays vector and selectable. Only the page box and the proportional scale of the content change; font data is untouched.
My output is slightly off my mm spec — why?
mm-to-point conversions rarely land on whole points (120 mm = 340.16 pt, not 340), and you type whole points. The result is sub-0.1 mm off. For exact print specs, ask whether your supplier accepts fractional points or round to their nearest acceptable value.
Can I crop to a custom size instead of scaling?
Yes, if you want to keep content at original scale and just trim the visible area — that's PDF Crop, which sets a crop box without shrinking content. Use resize to fit everything onto the new size; use crop to chop a smaller window out of each page.
How big a file can I resize?
Free: 2 MB / 50 pages. Pro: 50 MB / 500 pages. pro_media: 500 MB. Compress oversized files first with PDF Compress (Lossless).
Is anything uploaded?
No. The custom resize runs in-browser via pdf-lib; your bespoke artwork stays on your device. Only an anonymous file-processed counter is recorded for dashboard stats, with no content.
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.