How to Reduce HTML5 Banner File Size Below 150 KB

Hitting the strict 150 KB initial zip file size limit enforced by Google Ads, CM360, and major DSPs can be difficult for image-heavy creatives. Follow these proven compression strategies.

5 Actionable Compression Techniques

1. Convert PNGs to WebP / Lossy JPEGs: WebP files are up to 35% smaller than transparent PNGs while preserving image quality.
2. Use Google-Hosted CDN Libraries: Replace bundled GSAP or jQuery scripts with Google's allowlisted CDN URLs.
3. Inline SVGs for Logos & Icons: Vector graphics take up fractions of a kilobyte when inserted directly into the HTML document.
4. Minify CSS & JavaScript: Remove whitespace, console logs, and comments using Terser or CSSNano.
5. Strip Image Metadata (EXIF): Remove camera metadata from exported assets.

Check your final ZIP package size and file counts instantly with HTML5 Banner Validator.