About CompressThis

CompressThis does one thing: it makes files smaller. Drop a PDF, image, video, or Office document — get back a smaller version. No signup, no watermark, no upload limit.

It handles four types:

• PDF — pikepdf (wrapping qpdf) resamples embedded images and strips unused objects.
• Images (JPG, PNG, WebP, HEIC, GIF) — Pillow re-encodes at lower resolution and quality, same format as input.
• Video (MP4, MOV, AVI, MKV, WebM) — FFmpeg re-encodes to H.264 at a target resolution and CRF. Output is always MP4.
• Office documents (DOCX, PPTX, XLSX) — these are ZIP files internally; embedded images are resampled and re-encoded.

PDF, image, and Office files are processed entirely in memory and never written to disk. Video files are written to a temporary directory for FFmpeg processing, then deleted immediately — FFmpeg requires seekable file handles, so pure in-memory processing isn't possible.

No ML, no AI. Heuristic compression with deterministic settings.

CompressThis is a sister tool to PDFThis, which converts document photos to PDFs.