PDF 調整尺寸

直接在瀏覽器中將 PDF 頁面尺寸更改為 A4、Letter、Legal 或任意自訂大小。

將 PDF 拖曳至此處，或點擊選擇檔案

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PDF 調整為 A4 — 免費統一頁面大小

Convert any PDF to A4 page size (210×297 mm) for European/international submission, consistent printing, or matching paper standards. Our browser-side tool adjusts page dimensions while preserving content — text, images, layout stay exactly where they were. No upload, no sign-up, batch-mode supported.

100% FreeNo UploadNo Sign-upLossless Resize

使用步驟

Drop Your PDF: Drag PDFs in (Letter, Legal, A3, custom — any size). The tool detects current page dimensions automatically and shows them in a preview.
Select A4: Pick 'A4 (210×297 mm)' as the target size. Other sizes available: Letter, Legal, A3, A5, A6, and custom dimensions. Choose scale mode: 'Fit' (proportional, no cropping) or 'Stretch' (non-proportional, may distort).
Resize: Click 'Resize to A4'. pdf-lib processes every page in your browser. Aspect ratio is preserved by default — text and images stay in the same positions. A 50-page PDF typically resizes in 5-10 seconds.
Save: Download the resized PDF. All pages now have A4 dimensions. Open in any reader and print on A4 paper without scaling. Form fields, annotations, and metadata are preserved.

為何選擇此工具

100% Local Processing: Files are processed entirely in your browser using JavaScript — never uploaded to any server.
No Limits: No file count or file size restrictions. Process as many files as your device can handle.
No Sign-up: Free forever, no account needed, no email required. Open the page and start.
Private by Design: Nothing is sent to any server. Close the tab and your files are gone forever.

常見問題

How do I resize a PDF to A4?

Drop your PDF into our PDF Resize tool, pick 'A4' as the target size, and click 'Resize'. The PDF is processed locally and downloads with every page resized to A4 (210×297 mm). Text, images, and layout positions are preserved by default.

Will resize distort my content?

By default, no. We preserve aspect ratio and scale proportionally — content stays the same shape, just positioned within the new page size. For PDFs smaller than A4, content scales up to fit (or stays small with margins). For PDFs larger than A4, content scales down (or you can choose 'Fit to Page' which scales with white margins). For non-proportional stretching, enable 'Stretch' mode — this may distort circular elements or square images.

What about PDFs with mixed page sizes?

Each page is resized individually to A4. A PDF containing some Letter and some Legal pages will become fully A4 after resize. We preserve any page-specific properties (rotation, form fields) page by page.

Will my PDF be uploaded?

No. pdf-lib processes everything in your browser. For confidential documents (contracts, exam papers, financial reports), the file stays on your device the entire time.

Can I resize to sizes other than A4?

Yes — we support A3, A4, A5, A6, Letter, Legal, Tabloid, and any custom size (width/height in mm, cm, inches, or points). Pick from the preset list or enter your own dimensions. Useful for poster printing, business card PDFs, or matching specific paper requirements.

Is form field data preserved?

Yes — form fields, annotations, bookmarks, and metadata stay intact. The only change is the page box dimensions. AcroForm values render the same way they did before resize.