What is a good compression ratio?

It depends on the file type. Text files may compress at 4:1 or more, while already compressed files like JPEGs or MP3s may only see 1.1:1 or less.

Can I use this to check download time?

Yes. The calculator estimates how long it would take to download the original and compressed files over various internet speeds—helpful for download time estimators and transfer speed calculators.

Does this tool work for image batches?

Yes. You can input the number of images, and it will calculate total and per-image storage needs after compression.

How accurate are the results?

The estimates are based on typical compression ratios. Actual results may vary depending on file content and compression software used.

Can I use it as an iMac resource checker?

Yes, it's a handy way to understand how files impact storage and performance on your Mac. It supports macOS users managing data-heavy tasks like media editing or backups.

Compression Calculator

Author: Henrick Yau

- 26 October 2025

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Calculate file sizes, compression ratios, and storage requirements for different compression formats and quality settings.

File Compression Calculator

Original File Size:

Size of the uncompressed file

Compression Ratio:

Higher ratio = smaller file size

Compression Format:

Different formats have different typical compression ratios

File Type:

Compression effectiveness varies by file type

Audio/Video Compression Calculator

Audio

Video

Duration:

minutes

Audio Format:

Bitrate:

kbps

Channels:

Image Compression Calculator

Image Width:

Image Height:

Image Format:

Quality:

80%

Lower quality = smaller file size

Color Depth:

Number of Images:

For calculating batch compression

Storage Requirements Calculator

Content Type:

Number of Documents:

Average Size Per Document:

Additional Options:

Calculate with Compression

Include Backup/Redundancy (2x)

Understanding Compression

Data compression reduces file size by eliminating redundancy and representing information more efficiently. This saves storage space and reduces transmission time.

Compression Types

Lossless Compression: No information is lost during compression. Original data can be perfectly reconstructed (ZIP, PNG, FLAC).
Lossy Compression: Some information is permanently discarded to achieve higher compression ratios (JPEG, MP3, MP4).

Compression Ratio

Compression ratio is expressed as X:Y, where X represents the original size and Y represents the compressed size. For example, a 4:1 ratio means the original file was 4 times larger than the compressed version.

Space Saving: Calculated as (1 - 1/ratio) × 100%. For example, a 4:1 ratio saves 75% of space.
Compression Factor: Another way to express compression, calculated as original size ÷ compressed size.

Typical Compression Ratios

Text Documents: 2:1 to 8:1 with lossless compression
Images: 10:1 to 20:1 with lossy compression (JPEG), 2:1 to 5:1 with lossless (PNG)
Audio: 10:1 to 12:1 with lossy compression (MP3), 2:1 to 3:1 with lossless (FLAC)
Video: 20:1 to 200:1 with lossy compression, depending on quality

Disclaimer: This calculator provides estimates based on typical compression rates. Actual compression results may vary based on data characteristics, algorithm implementation, and compression settings. For precise measurements, use dedicated compression software on your actual files.