Compress PowerPoint (Reduce PPTX File Size)

Presentations get heavy because of pictures: a phone photo pasted onto a slide is often 4000 pixels wide and several megabytes, though a projector shows 1920. This tool opens the .pptx in your browser and shrinks every oversized picture to the size you choose. It recompresses JPEGs, turns opaque PNG screenshots into JPEG and can re-encode embedded MP4 videos. Everything else, including slides, text, animations, transitions, notes and layouts, is copied unchanged. The file never leaves your computer.

How to use this tool

1. Choose the .pptx file.
2. Pick the largest picture size: 1920 px suits screens and projectors, 1280 px is good for email.
3. Set the JPEG quality (75–85% looks the same on slides) and decide whether opaque PNGs may become JPEG.
4. Press Calculate and download the compressed presentation; the table shows what happened to each picture.

Formula

saving = 1 − new size ÷ original size · a picture is replaced only when its new version is at least 3% smaller

A .pptx file is a ZIP package, and its pictures live in ppt/media. Pictures larger than the limit are scaled down with high-quality smoothing and saved as JPEG at your quality. PNGs without transparency become JPEG, and the package's relationships and content types are updated to the new names. Transparent PNGs stay PNG and are only resized. JPEGs with an EXIF rotation tag are left alone, so no picture can turn sideways. EMF, WMF, SVG, GIF and TIFF pictures are not touched. Videos are re-encoded with H.264 at most 1280 px wide (CRF 28, AAC 96 kbit/s) when you tick the option.

Example

A 48 MB deck with 25 phone photos of 4032 × 3024 px each: at 1920 px and 80% quality each photo drops from about 1.8 MB to about 350 KB, so the 45 MB of photos become about 9 MB and the whole presentation shrinks to roughly 12 MB, about 75% smaller. The pictures look the same on screen, because the slide shows them at a fraction of their original width anyway.