# Compression Ratio Calculator

> Turn measured sizes before and after compression into a ratio and the space saved.

Page: https://freecalculator.tech/tools/compression-ratio-calculator
Last reviewed: 2026-09-17

## Formula

Ratio = S_uncompressed / S_compressed; Saved = S_uncompressed - S_compressed

- Ratio = S_uncompressed / S_compressed; Saved = S_uncompressed - S_compressed.
- Inputs used: Size before compression, Size after compression.
- Edge handling: Size before compression is required.; Size before compression cannot be negative.; Size before compression must be no more than 1000000000000.; Size after compression is required.; Size after compression cannot be negative..

## Inputs

- Size before compression
- Size after compression

## Worked example: 1,200 GB stored in 310 GB

Your own measured sizes before and after compression.
1. Start with Size before compression: 1200, Size after compression: 310.
2. Apply the method: Ratio = S_uncompressed / S_compressed; Saved = S_uncompressed - S_compressed.
3. Your own measured sizes before and after compression.

## Common questions

### Where does this formula come from?

DAMA-DMBOK data storage, integration and data-quality practice: volume growth is projected from measured history under a stated model; compression ratio is uncompressed size divided by stored size; throughput is volume processed divided by elapsed time; data currency (freshness) is the age of the data at the time it is used, measured against a stated requirement. See the source link on this page.

### What kind of calculation is this?

The uncompressed size as a multiple of the stored size, with the space saved and its share. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.

### What are its limits?

Arithmetic over the figures entered — it cannot tell whether the underlying metering, logs or job records are complete. A figure from one run or one period is a weak description of ongoing behaviour. A ratio measured on one sample does not transfer to other data. Compression and decompression time and cost are not considered.

### How do I use the Compression Ratio Calculator?

Enter the required values for Size before compression, Size after compression. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.

### What formula does the Compression Ratio Calculator use?

Ratio = S_uncompressed / S_compressed; Saved = S_uncompressed - S_compressed The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.

### Can the Compression Ratio Calculator be used for exact decisions?

Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.

## Limitations and assumptions

- Inputs outside the supported range are rejected rather than forced into a result.
- The result depends on the values you enter for this compression ratio calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.

## Sources

- DAMA International — https://www.dama.org/cpages/body-of-knowledge

## Cite this page

- APA: Free Calculator. (2026, September 17). Compression Ratio Calculator. https://freecalculator.tech/tools/compression-ratio-calculator
- MLA: "Compression Ratio Calculator." Free Calculator, 17 Sept. 2026, https://freecalculator.tech/tools/compression-ratio-calculator.
- Link: Compression Ratio Calculator — Free Calculator, https://freecalculator.tech/tools/compression-ratio-calculator