Increase File Size Online — Free, Exact, Nothing Uploaded
This free tool increases a JPG, PNG or PDF to an exact file size — 20KB, 100KB, 2MB or any figure you type — by padding it with data that decoders ignore, so the file looks exactly the same. Everything happens in your browser, and your file is never uploaded to a server.
Increase any file to an exact size
Runs entirely in this browser tab. Your file is never uploaded.
Drag a JPG, PNG or PDF file here, or
Nothing is uploaded when you pick a file.
How it works
- 1
Choose your file
Drag a file onto the tool above or click to browse. It accepts JPG, PNG and PDF files, and the file is read directly by your browser rather than sent anywhere.
- 2
Set your target size
Pick a preset from the dropdown or type an exact figure in KB or MB. The output will match that number byte for byte.
- 3
Choose how the size is added
The default pads the file with metadata areas that the file format reserves for data decoders ignore, so the image is untouched. Switch to "increase resolution" if you want more pixels as well as more bytes.
- 4
Download the result
Press the button and your browser saves the new file at exactly the size you asked for. Nothing was uploaded, so there is nothing stored anywhere for you to delete afterwards.
What the tool actually does to your file
A JPG is padded with COM comment segments, a PNG with ancillary tEXt chunks, and a PDF with an inert stream object. Each of those is a part of the format that its own specification tells readers to skip, which is why the output opens normally everywhere and looks identical to the original — the compressed image data is never decoded or rewritten.
If you want a genuinely larger image rather than a larger file, switch the tool to “increase resolution”. That redraws the image at more pixels using the Canvas API and then pads the result to your exact target, so you get both a real resolution increase and the byte count the form is asking for.
Pick your exact size
Each of these pages loads the tool pre-set to that target, with the details specific to it.
Any file type
JPG
PNG
Frequently asked questions
Will this reduce my image’s quality?
No. The padding goes into metadata areas that the file format reserves for data decoders ignore, so the image data is never decoded or re-compressed. What comes out is pixel-for-pixel identical, just larger on disk.
Is my file uploaded to a server?
No, and you do not have to take that on trust. Load this page, disconnect from the internet, and use the tool — it still works, which it could not do if your file had to reach a server. Nothing is transmitted, so there is nothing stored and nothing to delete afterwards.
What file formats are supported?
JPG (including .jpeg), PNG and PDF. Each one is padded using the structure its own specification reserves for data readers can ignore, so the output is always a valid file of that type.
Why would I need to increase file size instead of decrease it?
Because some upload forms enforce a minimum as well as a maximum. The minimum is meant to reject scans too low-quality to read, but it catches efficiently compressed files too. When your file is legible and simply small, making it bigger is the only thing standing between you and a successful submission.
Is this free to use?
Yes — free, with no account, no watermark, no email address and no limit on how many files you run through it. Because the work happens on your own device rather than on a server, there are no processing costs to pass on.
From the blog
- KB vs MB: What's the Difference and Why It Matters for UploadsOne megabyte is 1,024 kilobytes. That single conversion is behind most rejected uploads — here is how to read a form’s size limit correctly.
- Why Do Some Upload Forms Require a Minimum File Size?Minimum size rules are a crude proxy for image quality. Here is what the people who wrote those rules were actually trying to prevent.
- Does Increasing File Size Reduce Image Quality? (Explained)Padding a file cannot reduce its quality, because it never touches the image data. Re-encoding can. The difference matters.
- File Size vs Resolution: They're Not the Same ThingResolution is how many pixels an image has. File size is how many bytes it takes to store them. Either can change without the other.