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Cách Thay Đổi Kích Thước Trang PDF: Hướng Dẫn Toàn Diện Về Thay Đổi Kích Thước Trang

Học cách thay đổi kích thước trang PDF thành A4, Letter, Legal hoặc kích thước tùy chỉnh. Hiểu kích thước trang, chế độ tỷ lệ và khi nào nên thay đổi kích thước PDF.

Xuất bản 26 tháng 1, 2026

Understanding PDF Page Sizes

PDF documents can have different page sizes, which affects printing and display. Understanding common sizes helps you choose the right dimensions for your needs.

Common Page Sizes

Standard Paper Sizes

SizeDimensions (inches)PointsCommon Use
A48.27 x 11.69595 x 842International standard
Letter8.5 x 11612 x 792US standard
Legal8.5 x 14612 x 1008Legal documents
A311.69 x 16.54842 x 1191Posters, technical
A55.83 x 8.27420 x 595Booklets, flyers

Why Size Matters

  • Printing - Wrong size causes cropping or scaling
  • Compatibility - US vs international standards differ
  • Display - Affects readability on screen
  • File size - Larger pages = larger files

How to Resize PDF Pages

Use our Resize PDF tool to change page dimensions:

  1. Upload your PDF document
  2. Select a preset size (A4, Letter, etc.) or Custom
  3. Choose orientation (Portrait, Landscape, or Keep)
  4. Select scaling mode (Fit, Fill, or Stretch)
  5. Click Resize PDF
  6. Download your resized document

Understanding Scaling Modes

Fit Mode (Recommended)

Scales content to fit entirely within new dimensions:

  • Maintains aspect ratio
  • No content is cropped
  • May have white margins
  • Best for preserving all content

Fill Mode

Scales to cover the entire page:

  • Maintains aspect ratio
  • Some content may be cropped
  • No white margins
  • Best for visual impact

Stretch Mode

Stretches to exactly fill new dimensions:

  • Does NOT maintain aspect ratio
  • Content may appear distorted
  • Fills page completely
  • Use sparingly

Common Scenarios

A4 to Letter Conversion

Converting between international (A4) and US (Letter) sizes:

  • A4 is slightly narrower and taller than Letter
  • Use Fit mode to avoid cropping
  • Minor margins may appear

Preparing for Print

Ensure your PDF matches printer settings:

  • Check your printer's default paper size
  • Resize PDF to match exactly
  • Use "Actual Size" when printing

Creating Booklets

Resize to A5 for booklet printing:

  • Start with A4 content
  • Resize to A5
  • Print multiple pages per sheet

Custom Dimensions

For non-standard sizes, enter dimensions in points:

  • 72 points = 1 inch
  • 28.35 points = 1 cm
  • Calculate: inches x 72 = points

Examples

  • 5x7 inches = 360 x 504 points
  • 6x9 inches = 432 x 648 points
  • Square 8x8 = 576 x 576 points

Orientation Options

Portrait

Taller than wide - standard for documents:

  • Letters and reports
  • Books and articles
  • Most printed materials

Landscape

Wider than tall - good for:

  • Presentations
  • Certificates
  • Wide tables and charts
  • Photos

Keep Original

Maintains each page's original orientation:

  • Mixed orientation documents
  • Scanned materials
  • Varied content types

Best Practices

Before Resizing

  1. Know your target size requirements
  2. Check current page dimensions
  3. Consider content layout
  4. Keep original as backup

Quality Considerations

  • Vector content (text, shapes) scales perfectly
  • Images may lose quality if enlarged
  • Significant size increases can affect clarity
  • Test with a single page first

Related Tools

Combine resizing with other PDF adjustments:

Conclusion

Resizing PDF pages ensures your documents print correctly and display well across different devices. Use our Resize PDF tool to quickly convert between A4, Letter, and other standard sizes while preserving your content quality.

Công Cụ Được Đề Xuất

Hãy thử các công cụ này để hoàn thành các nhiệm vụ được đề cập trong hướng dẫn này:

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