About SizeItDown
Most "resize my image" tools give you a quality slider and hope. SizeItDown works backwards from a byte budget instead — tell it the file size you need, and it finds the highest quality that still fits, trading resolution away only when quality alone can't get there. It exists because that specific problem — "I need this file under a specific size, not just smaller" — comes up constantly (an upload cap, an email attachment limit, a page-speed budget) and most tools answer a different question than the one being asked.
What it does
- Compresses JPEG, PNG, WebP, GIF, AVIF, BMP, and HEIC/HEIF images to a target file size.
- Compresses MP4, MOV, WebM, and AVI video to a target file size (best-effort).
- Batch processing — drop a whole folder of images (or videos, on the video page) and compress them all in one go.
- A pre-compression editor for crop, rotate, flip, aspect ratio, and focus point, so you don't need a separate image editor first.
- No account required, no cloud storage — files are processed and then discarded.
How the target-size search works
JPEG and WebP: binary search encoder quality between a perceptual floor and the format's maximum, at the image's current width, checking the result against your target at each step. Nothing fits above that floor? The width steps down (roughly 15% at a time) and the quality search runs again at the smaller size. Resolution only gets traded away once quality genuinely can't reach the target on its own — never before. PNG doesn't have a quality dial to begin with, being lossless; its lever is palette size, so a PNG search trims distinct colors instead. The mechanics in full, including why re-compressing an already-compressed file backfires, live in the quality guide; which format to reach for and why is in the format guide.
One thing it won't do: quietly pick a winner when a minimum-resolution floor and a target size can't both be satisfied. You get shown the smallest file that respects your resolution floor and the smallest resolution that actually hits your target, side by side, and you choose.
Why you can trust it with your files
- No signup, no account, no login wall — open the page and use it.
- Uploaded files are processed in memory or a short-lived temp location only for as long as compression takes, then discarded. Nothing is stored, viewed, or shared. See the Privacy Policy for the exact retention details, including the 90-day metadata-only audit log kept for abuse prevention.
- Free because it's ad-supported, not because your files are the product — see the Privacy Policy's Advertising section for what that involves.
- The compression logic isn't a black box — the quality guide above walks through exactly what quality it picks and when it reaches for resolution instead.
Who's behind this
One person, not a company. Every choice on this page — an accurate error message over a silent guess, showing a conflict instead of resolving it for you quietly — is a decision made and stood behind directly, not filtered through a product team. Found something wrong, broken, or missing? The email below reaches the person who can actually fix it, not a ticket queue.
Contact
Questions or feedback: [email protected]