01
Convert the target to bytes
The KB value is converted to bytes (KB × 1,024), and every candidate result is compared with that limit.
WebP Compression
Compress WebP precisely for modern web delivery
A helpful option for creators and teams who need smaller WebP images without spending time on repeated exports.
Free
No signup
Private
Use the compressor at no cost.
Open the tool and start compressing immediately.
Compression stays in your browser and files are not stored on our servers.
Common use cases
Optimizing product images for ecommerce pages
Compressing featured images for WordPress and blogs
Preparing lightweight blog and landing page assets
Meeting strict CMS media limits without guesswork
Reducing marketplace and storefront image weight
Start compressing
Set your target size, let the tool do the work, and download the result when it is ready.
What this tool does
This tool compresses WebP files toward a target KB or MB size directly in your browser. Choose the limit from your form, run compression, then review the result before your final upload.
Practical tips
- Use WebP for web images, CMS uploads, ecommerce, and pages that accept modern image formats.
- For older portals, keep JPG or PNG if the upload form specifically asks for them.
- Reduce dimensions if quality changes alone cannot reach the target.
Verifiable method
How ExactSizer targets a file-size limit
The target is treated as a maximum limit, not a promise that every source file can finish at exactly the same byte count.
02
Search for the highest usable image quality
For JPG, PNG, and WebP, the engine tests quality between 0.1 and 1.0 using 12 binary-search steps. If that is not enough, dimensions decrease in 5% increments down to a minimum of 10% of the starting dimensions. To bridge encoder size plateaus, it also tests higher-quality candidates and refines dimensions in 6 passes, always retaining the closest result under the limit.
03
Process locally and report the result honestly
The file is processed in browser memory. The result reports whether the target was met and shows a warning if minimum settings are reached before the requested size.
Popular target sizes
Many people land on pages like this because they need a specific number, not just a smaller file. These are some of the most common targets in this niche.
Common search
WebP to 30KB
Use this page when you need to compress WebP to around 30KB for upload rules, forms, or sharing limits.
Common search
WebP to 50KB
Use this page when you need to compress WebP to around 50KB for upload rules, forms, or sharing limits.
Common search
WebP to 100KB
Use this page when you need to compress WebP to around 100KB for upload rules, forms, or sharing limits.
Common search
WebP to 150KB
Use this page when you need to compress WebP to around 150KB for upload rules, forms, or sharing limits.
Common search
WebP to 1024KB
Use this page when you need to compress WebP to around 1024KB for upload rules, forms, or sharing limits.
Frequently asked questions
These answers cover the questions people usually have before compressing a file.
Why use WebP for exact-size compression?
WebP often reaches smaller file sizes than older formats, so it can be a good choice for modern websites and lighter media libraries.
Can I use this for marketplace images?
Yes. WebP is useful when you need lighter images for faster pages or to stay within platform media limits.
Is WebP supported everywhere?
Most modern browsers support WebP well, but if you need broad compatibility for older systems, JPG or PNG may still be the safer choice.
Related resources
Useful next pages for common targets, format changes, and upload problems.
Also useful
Image to 200KB
For photos, forms, and images that need more clarity.
Also useful
Image to 500KB
For CMS images, product photos, and less aggressive limits.
Also useful
Image upload failed
Fix image size, format, and dimension upload errors.
Also useful
Compress JPG or HEIC to an Exact KB Size
Reduce JPG, JPEG, and iPhone HEIC files to the size you need for forms, portals, and everyday uploads.
Also useful
Compress PNG to an Exact KB Size
Shrink PNG images to the size you need while keeping screenshots, artwork, and graphics clear.
Also useful
Image Upload Failed? Fix Size, Format, and Dimensions
A clear image upload failed solution for photos, signatures, screenshots, and portal images rejected by size, format, or dimension rules.