How to reduce file size

Images are the most impactful category for file size reduction, especially on websites. The three main levers are format, quality, and dimensions.

Switch to WebP. WebP achieves 25–35% smaller file sizes than JPG and 30–50% smaller than PNG at the same visual quality. All modern browsers support it. Converting your JPG and PNG images to WebP is the single highest-impact image optimization you can make.

Use JPG for photographs, PNG for graphics. JPG compresses photographs efficiently (60–80% smaller than PNG). PNG is better for logos, icons, and screenshots with flat colors or transparency. Using JPG for a photograph that was saved as PNG often reduces file size by 70–80% instantly.

Convert BMP immediately. BMP files are completely uncompressed — a single screenshot can be 10 MB. The equivalent JPG is under 200 KB. If you have BMP files, converting them to JPG or PNG is the fastest size reduction possible.

Convert WAV to MP3 or OGG. WAV is uncompressed — a 3-minute song takes 30–40 MB. At 192 kbps MP3, the same track is 4–5 MB. For most listening purposes, the difference is inaudible. Reserve WAV for audio editing workflows where you need lossless quality.

Bitrate matters more than format. A 320 kbps MP3 is larger than a 128 kbps MP3. For podcast voice audio, 128 kbps mono is indistinguishable from higher bitrates and is half the size of 256 kbps stereo.

Convert GIF to MP4. GIF is the most inefficient video format ever created. Converting an animated GIF to MP4 typically reduces file size by 90%. A 15 MB GIF becomes under 1 MB as MP4.

Use WebM for web video. WebM with VP9 codec achieves 30–40% better compression than H.264 MP4 at equivalent quality. For self-hosted web video, serving WebM to modern browsers (Chrome, Firefox) and MP4 as fallback gives you the best of both worlds.

Convert AVI to MP4. AVI files using older codecs (DivX, Xvid, MJPEG) are often 20–50% larger than the equivalent H.264 MP4. Converting legacy AVI archives to MP4 saves space and improves compatibility.

Use PDF for sharing, DOCX for editing. PDFs are typically smaller than DOCX for the same content because they don't carry the metadata and styles Word stores. For final documents that don't need editing, PDF is the right choice.

Convert EPUB to MOBI/AZW3 instead of PDF for e-readers. EPUB and MOBI/AZW3 files are typically 40–70% smaller than equivalent PDFs, and they offer better reading experiences on e-readers.