How to compress a PDF and choose the right quality
A smaller PDF is easier to send, but smaller is not automatically better. Start by deciding whether you need selectable text, clear small lettering or simply a smaller scanned document.
Understand the task first
This tool offers Safe optimize, Balanced and Strong. Safe optimize rewrites the PDF while keeping text objects. Balanced and Strong render pages into images. That trade-off can reduce size, but can also remove text selection and search, and flatten interactive elements.
A small worked example
A hypothetical 8 MB file becomes 6 MB: saved size = 2 MB; reduction = 2 ÷ 8 × 100 = 25%. The new size is 75% of the original. This arithmetic example is not a compression promise.
Follow these steps
Keep a readable original
Save an untouched copy. For signed, fillable or accessibility-sensitive documents, think carefully before any rewrite or image conversion. A smaller file is not worth losing a required document feature.
Start with Safe optimize
Select the file and leave the mode on Safe optimize when searchable text matters. Wait for the local check, then run compression. An already optimized PDF may not get smaller.
Compare actual sizes
Read the before and after sizes. Reduction = (old size − new size) ÷ old size × 100. For 8 MB to 6 MB, the reduction is 25%, not 75%. Use the same units for both sizes.
Trade quality only when appropriate
If more reduction is needed and losing selectable text is acceptable, try Balanced on the original. Try Strong only after checking Balanced. The names describe intended trade-offs, not a guaranteed output size.
Check the downloaded copy
Open the output, zoom into small text, inspect diagrams and check every page. Try selecting or searching text when needed. Share only the version that remains fit for your purpose.
Try the actual tool
The tool below is the same one used on the standalone tool page. Your document is processed locally.
or click to choose
PDF uploads are checked by the Content Guard workflow before file processing.
Balanced and Strong flatten pages into images, so text may no longer be selectable or searchable. Use Safe optimize when that matters.
Check your understanding
Read the explanation
Start with Safe optimize, then check the downloaded result. Balanced and Strong turn pages into images, which is a different trade-off.
Avoid the common trap
Do not promise a fixed percentage reduction. Do not repeatedly recompress an already rasterized output to chase size; compare alternatives made from the original. A smaller PDF can be harder to read or less accessible.
When this method applies — and when it does not
Processing happens locally in the browser; the compression result depends on the document and selected mode. This is not a way to remove passwords, repair every damaged PDF or guarantee preservation of digital signatures, forms or accessibility tags.
One idea understood. Keep going.
This optional checkmark is saved only in this browser. It is your own progress note, not a certificate.
Sources & further reading
References open in a new tab and explain the underlying principles. The teaching text and examples here are SimpleFlick’s own; the source organisations have not endorsed this calculator.
Lesson updated: · Instructions checked against this release’s interface. Review the downloaded document before using it.