Image upscaler: enlarge a photo without uploading it
Drop your image, pick a factor (2x to 8x) or a width in pixels, then run the upscale. The tool uses Lanczos resampling followed by an unsharp mask. This is classic math, not AI: it makes the image larger and crisper, but it cannot invent detail that was never captured.
- ✅ Free
- 🔒 No sign-up
- 📱 Works on mobile
- ⚡ Instant results
🔒 Everything runs in your browser. Your data and files never leave your device.
📌 Key facts
- This image upscaler enlarges a picture with Lanczos resampling, then applies an adjustable unsharp mask.
- There is no AI: the tool cannot invent detail that was never captured, it only makes the image larger, cleaner and crisper.
- Factors run from 2x to 8x, or you can set a target width from 16 to 16,384 px; a Pixel art mode keeps pixels as crisp squares.
- The output cannot exceed 40 million pixels or 16,384 px on one side.
- Export as PNG, JPG or WebP, with sharpening set to 60% by default.
- Everything runs in your browser, so the image is neither uploaded nor stored.
What upscaling really does
Enlarging an image means computing pixels that never existed. A plain stretch copies neighbors and gives blocks or blur. Lanczos resampling computes each new pixel as a weighted average of the surrounding 6 × 6 pixels, using a filter that preserves edges better.
The unsharp mask then adds local contrast by subtracting a blurred copy from the image itself.
\[ \text{sharpened pixel} = \text{original} + \text{amount} \times (\text{original} - \text{blurred copy}) \]
This tool does not use artificial intelligence. It will not rebuild a blurry face or an unreadable sign. It makes the picture larger, cleaner and crisper, and that is all.
Sizes and limits
| Starting size | 2x | 4x |
|---|---|---|
| 640 × 480 (0.3 MP) | 1,280 × 960 | 2,560 × 1,920 |
| 1,920 × 1,080 (2 MP) | 3,840 × 2,160 | 7,680 × 4,320 |
| 3,000 × 2,000 (6 MP) | 6,000 × 4,000 | refused (too large) |
Output is capped at 40 million pixels and 16,384 pixels on a side so your browser does not run out of memory. The tool tells you the maximum factor you can use.
Getting the best result
- Start from the largest, least compressed image you have.
- Enlarge once: 2x or 4x beats several small enlargements in a row.
- Keep sharpening between 40 and 80%; set it to 0% if the image is already very contrasty.
- For print or display, the real gain is mostly file size and smoothness, not new detail.
How to use the image upscaler in 4 steps
- First, drop your image in the box above.
- Next, choose a factor (2x to 8x) or a width in pixels.
- Then set the sharpening, or switch to Pixel art mode for a sprite.
- Finally, run the calculation and download the result as PNG, JPG or WebP.
To use an image upscaler with no surprises, start with 2x. If the result stays crisp, try 4x. That way you quickly find the limit of your source.
The image upscaler also lets you compare before and after. So zoom in on a sharp edge, such as text or a hairline. If you see halos, lower the sharpening and run it again. Because everything runs locally, you can repeat this as often as you like.
Which factor to pick in an image upscaler
| Need | Suggested setting | Note |
|---|---|---|
| Profile picture that is too small | 2x | Best balance of crispness and natural look |
| Poster from a clean image | 4x | Detail stays what the source had |
| Sprite or pixel art | 8x in Pixel art mode | Pixels stay crisp squares |
| Width set by a website | Width in pixels | The height works itself out |
When you need an exact width, use the Width field in this image upscaler. It keeps the proportions. So the picture does not stretch.
Common mistakes with an image upscaler
- Expecting a miracle on a blurry photo, since no tool makes a face readable again.
- Starting from a heavily compressed JPEG, because its blocks grow too.
- Pushing the sharpening to the maximum, which draws halos around edges.
- Enlarging several times in a row, when one enlargement gives a better result.
For example, to enlarge an 800 x 600 px picture, go straight to 4x instead of three rounds of 1.5x. If the tool refuses, the result would exceed 40 million pixels. Then pick a smaller factor. The tool shows the maximum factor your picture allows, so use that number as your ceiling.
After the upscale: edit and slim down
When the image upscaler finishes, the file gets heavier. So plan a finishing step.
- To hit an exact size, use resize image.
- To shrink the final file, open compress image.
- To cut unneeded edges, try crop image.
- To switch formats, go through the PNG to JPG converter.
Large files take longer to save, so give the image upscaler a moment on big pictures. Finally, to fix light or color, open the photo editor.
3 real-life examples
An 800 × 600 photo for a poster
Go from 800 × 600 to 3,200 × 2,400 at 4x. The poster looks smoother than with a plain stretch, though it will still be less detailed than a real high-resolution photo.
A pixel art icon
Your 32 × 32 px sprite becomes 256 × 256 in "Pixel art" mode: pixels stay crisp squares with no blur.
A 1,000 px image for a banner
You need a 1,920 px width. Choose "Width…", type 1920: the tool works out the height and applies 60% sharpening.