Resize image online
Type the exact width and height a form, a platform, or a design demands — resized on your own device, aspect ratio protected until you say otherwise.
Drop your image here
or
JPG, PNG, WebP, HEIC, SVG — any size, no upload
🔒 Files never leave your device — everything runs in your browser.
Resizing is the most-demanded image edit there is: a portal wants exactly 600×600, a listing rejects anything over 1200 pixels, an avatar field crops whatever doesn't fit, a slide needs a picture at half its bulk. This tool takes exact pixel dimensions — type either one and the aspect lock computes the other from your image, or use the 75/50/25 percent presets — and re-renders on your device. Batches work too: every file gets the same box, its own result, and its own original name.
Two honest behaviors most resizers hide: unlocking the aspect ratio stretches the image to exactly the box you typed (the tool says so before you run it, because stretched faces are usually an accident), and enlarging past the original size cannot invent detail — you get the pixels you asked for with the softness upscaling always brings. Output stays in your image's own format by default, or switch to JPG, PNG, or WebP in the same pass.
How it works
- Drop your file
Any common format, any size. Nothing is uploaded — the tool runs in your browser.
- Choose quality or size
Pick a quality preset, set an exact KB target, or switch the output format — tuned for resize image.
- Download
Your converted file is ready on your device — nothing to wait for, nothing to delete from a server.
Frequently asked questions
How do I resize to an exact size like 600×600?
Type 600 into both fields. If your image isn't square, either leave the aspect lock on and crop to a square first in any editor (no distortion), or unlock the ratio and accept the stretch — the tool warns you which trade you're making before anything runs.
Will resizing reduce my image quality?
Downscaling keeps images crisp — it is the safest resize direction. Upscaling cannot add detail that was never captured, so enlarged images come out softer; the tool tells you when your target exceeds the original. Either way the resample happens once, at high quality, on your device.
Can I resize many images at once?
Yes — drop a batch and every image is resized to the same pixel box, each with its own download and its original filename. For mixed orientations, note the box applies as typed: portrait and landscape files get the same dimensions.
Does the image leave my device?
No. Decoding, resampling, and re-encoding all run in your browser — there is no server that could receive your photos. That matters for exactly the images people resize: IDs, applications, and family photos.
Is my file uploaded to a server?
No. ConvertUno runs entirely in your browser on your own device. Your file never leaves your computer or phone — there is no upload at all.
Is it really free, with no watermark?
Yes. Processing happens on your device, so serving you costs us almost nothing — no watermark, no account, no file-size limit, no daily quota.