PDF File Size Calculator
Estimate how large your PDF will be before you create it. Adjust page count, images, and resolution to see the estimated file size.
1.34 MB
Based on A4 pages with JPEG-compressed images. Actual size may vary based on content.
Already have a large PDF? Reduce its size instantly.
Compress PDF — FreeHow PDF file size is calculated
PDF file size depends on three main factors: text content, embedded images, and font data. Text-only PDFs are small — typically 3-5 KB per page plus a one-time font embedding cost of 30-80 KB. Images are the main driver of file size. A single full-page photo at 300 DPI adds roughly 500 KB to 2 MB depending on compression.
Why DPI matters for PDF size
DPI (dots per inch) determines image resolution. At 72 DPI (screen quality), a full-page image is about 600×850 pixels — small and fast to load. At 300 DPI (print quality), the same image is 2480×3508 pixels — 17× more data. Unless you're printing professionally, 150 DPI is the best balance of quality and file size.
Tips to keep PDFs small
- Use 150 DPI instead of 300 DPI for documents that won't be professionally printed
- Compress images before embedding them in your PDF
- Avoid embedding full fonts — use font subsetting to include only the characters you need
- Remove metadata, bookmarks, and annotations you don't need
- Use a PDF compressor like WhiskFile Compress PDF to optimize after creation