Video Compression Ratio Calculator
Quantifying What a Codec Actually Saved
Compression ratio turns a before-and-after file size comparison into a single, comparable figure — useful when deciding between encoding settings, evaluating a new codec, or reporting how much space a transcoding pipeline reclaimed. A ratio of 5:1 means the original file was five times the size of the compressed one; the accompanying percentage figure states the same relationship as space saved.
The Formulas
Space Saved(%) = (1 − Compressed Size ÷ Original Size) × 100
Worked Example
| Metric | Value |
|---|---|
| Compression ratio | 5.294:1 |
| Space saved | 81.11% |
A ratio above roughly 4:1 to 6:1 is typical for modern codecs like H.265/AV1 transcoding a high-bitrate master down to a distribution-friendly file, though the exact figure depends heavily on source complexity and target quality settings.
Where This Matters
- Evaluating a new codec or encoder preset — compressing the same source with two different settings and comparing ratios shows which one saves more space for a similar visual result.
- Justifying a transcode pipeline — reporting "reduced storage by 81%" is a clearer statement to stakeholders than raw before/after megabyte figures.
- Estimating archive size before a batch job — testing compression ratio on a representative sample file lets you project the total space an entire library will occupy after transcoding.
How to Use This Calculator
- Enter the Original Size in MB.
- Enter the Compressed Size in MB.
- Select Calculate to see the compression ratio and the percentage of space saved.
Related Calculations
Estimate a file's size before you compress it with the Video File Size Calculator, or project storage needs across a full recording schedule with the Video Storage Requirement Calculator.