Service Worker Cache Size Estimator
Enter the URLs in your service worker precache manifest to estimate total cache storage, GZIP and Brotli sizes for each asset type, and get specific compression recommendations. Runs entirely in your browser — no network requests, no signup required.
Enter the URLs in your service worker precache manifest — the tool estimates total cache storage, GZIP and Brotli sizes for each asset type, and recommends compression strategies. Runs entirely in your browser. No network requests are made.
Leave "Known size" blank to use typical sizes for each asset type. Enter the actual file size in KB for more accurate estimates.
Why Use Our Service Worker Cache Size Estimator?
Instant Cache Size Estimation
Paste your precache URL list and instantly see total cache storage, GZIP size, and Brotli size — with per-asset breakdown and compression strategy for each file type.
Secure Service Worker Cache Estimator Online
All estimation runs entirely in your browser. No URLs are fetched and no data leaves your device — safe for analyzing internal or staging environment URLs.
Per-Asset Compression Recommendations
Each asset type gets a specific compression strategy — from enabling Brotli for JS/CSS to switching to WOFF2 for fonts and WebP for images.
100% Free Forever
Estimate as many precache manifests as you need, completely free. No account, no subscription, no limits, and no ads.
Common Use Cases for Service Worker Cache Size Estimator
PWA Precache Manifest Planning
Before deploying a new service worker, estimate the total precache download size to ensure it stays within the 50 MB storage quota recommended for mobile devices.
First Install Performance Budget
Calculate how much data users download on first PWA install — use the estimate to identify large assets that should be lazy-loaded rather than precached.
Cache Storage Quota Debugging
Diagnose why your PWA is hitting storage quota limits — identify which asset types are consuming the most cache space and which can be removed or compressed.
Compression Strategy Audit
Identify which assets in your precache list are not benefiting from HTTP compression — get specific recommendations for each file type to reduce transfer size.
Workbox Configuration Review
Review your Workbox precache configuration before deployment — estimate the impact of adding or removing assets from the manifest on total cache size.
CDN Bandwidth Cost Planning
Estimate the bandwidth cost of serving your precache assets with and without compression — calculate monthly savings from enabling Brotli on your CDN.
Understanding Service Worker Cache Size
What is a Service Worker Cache Size Estimator?
A service worker cache size estimatorcalculates the total storage consumed by a list of URLs in a service worker precache manifest — and estimates how much smaller each asset would be with GZIP or Brotli compression. Service workers cache assets locally on the user's device for offline access and faster repeat loads. Our free tool analyzes each URL's file extension to determine its asset type, applies typical compression ratios, and gives specific recommendations for reducing cache size.
How Our Service Worker Cache Size Estimator Works
- Enter Your URLs: Paste the URLs from your service worker precache manifest — one per row. Optionally enter the known file size in KB for each URL.
- Instant Browser-Based Estimation:Click "Estimate Cache Size" — the tool detects each asset type from the URL extension, applies typical compression ratios, and calculates total cache size. No network requests are made.
- Review Recommendations: Each asset gets a specific compression strategy — from enabling Brotli for text assets to switching formats for images and fonts.
What Gets Analyzed
- Asset Type Detection: URL extensions are used to classify each asset as HTML, CSS, JS, JSON, image, font, audio, video, or binary.
- Compression Ratios: Each asset type has typical GZIP and Brotli compression ratios — text assets compress 70–85%, while binary formats gain almost nothing.
- Total Cache Size: Raw, GZIP, and Brotli totals are shown so you can see the impact of enabling server-side compression on your precache download.
- Per-Asset Strategy: Each asset gets a specific recommendation — from enabling Brotli to switching to WOFF2 for fonts or WebP for images.
Service Worker Storage Quotas
Browsers impose storage quotas on service worker caches. Chrome and Edge allow up to 60% of available disk space, but the practical limit for a good user experience is 50 MB for the initial precache. Large precache manifests delay the first install and can cause quota errors on low-storage devices. Use this estimator to keep your precache lean — lazy-load large assets instead of precaching them.
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Frequently Asked Questions About Service Worker Cache Size Estimator
A service worker cache size estimator calculates the total storage consumed by a list of URLs in a service worker precache manifest and estimates GZIP and Brotli sizes for each asset. Our free online service worker cache size estimator runs entirely in your browser — no network requests are made and no data leaves your device.
No. The tool estimates sizes based on the URL file extension and typical sizes for each asset type. If you know the actual file size, enter it in the "Known size (KB)" column for a more accurate estimate. This approach works without network access and is safe for internal or staging URLs.
Yes, complete privacy is guaranteed. All estimation runs entirely client-side in your browser. No URLs are fetched and no data leaves your device — safe for analyzing internal, staging, or production URLs that may contain sensitive path information.
Yes. The service worker cache size estimator is 100% free with no signup, no subscription, no URL limits, and no ads. You can estimate as many precache manifests as you need.
The practical recommendation is to keep your initial precache under 50 MB for a good user experience on mobile devices. Chrome and Edge allow up to 60% of available disk space, but low-storage devices may have much less. Large precache manifests also delay the service worker install event, which can hurt first-load performance.
Raster images (JPEG, PNG, WebP, AVIF) and audio/video files are already compressed using their own codecs — applying HTTP compression on top adds almost nothing and wastes CPU. WOFF2 fonts are already Brotli-compressed internally. For these asset types, the tool recommends format-level optimizations instead (e.g. WebP for images, WOFF2 for fonts).
If you use Workbox, the precache manifest is generated during your build process — look for the workbox-precache-manifest.*.js file or the injected manifest in your service worker. For manual service workers, list the URLs you pass to cache.addAll() in your install event handler.
Precaching downloads and stores assets during the service worker install event — before the user navigates to any page. Runtime caching stores assets on demand as the user navigates. Precaching guarantees offline availability but increases install size; runtime caching is more flexible but does not guarantee offline access.