Summary Compression Ratio Calculator
Enter the original and summary word counts to see the compression ratio, the reduction, the words removed, and how many times shorter the summary is.
Compression
A very low ratio (a heavy cut) is efficient, but check that the summary still carries the source’s main claim, method, and caveats — compression should not mean losing the argument.
Measuring a summary — and sanity-checking it
Compression ratio puts a number on how hard a summary squeezes its source. It is handy for comparing summaries, setting a length target, or judging whether an AI-generated abstract is a genuine condensation or has simply thrown text away. A lower ratio means a heavier cut.
The number is only half the story. A short summary is efficient only if it preserves the source’s main claim, method, and caveats. When the ratio is very low, read the summary back against the original and check that the argument — not just the word count — survived.
Frequently Asked Questions
What is a compression ratio?
It is the summary's length divided by the original's length, shown as a percentage. A 1,000-word source cut to a 200-word summary has a 20% compression ratio — the summary keeps a fifth of the words. The reduction (80%) is how much was removed.
What compression ratio should I aim for?
There is no single right number — it depends on the source and your purpose. An abstract might be 5% of a paper, a study summary 20–30%. The useful question is not just how short the summary is, but whether it still carries the main claim, method, and key caveats.
Can a summary be too compressed?
Yes. Very aggressive compression risks dropping the argument's nuance, conditions, and limitations — exactly the parts an AI summary tends to smooth over. If the ratio is very low, re-read the summary against the source to confirm nothing essential was lost.
Educational tool only. A ratio measures length, not whether the summary is accurate — always verify against the source.