PNG to PDF Converter
Turn PNG images into a PDF without uploading anything. It reads the real pixel dimensions of every file, keeps transparency where you want it and composites it onto a background where you do not, and warns you when an image is too small to print cleanly at the size you have chosen. The whole thing happens in this browser tab.
- Nothing uploaded
- Works with no signal
- No sign up
- Searchable output
Nothing added yet. Each image becomes one page, in the order shown.
Page preview
Showing page 1.
Nothing here is uploaded. The images are read by this page, the PDF is assembled in memory, and the download comes from your own machine. Close the tab and it is all gone.
Your files never leave this device.The images are read by your browser, the PDF is built here in the page, and the download comes from your own machine. Nothing is sent to a server, so nothing is stored on one. Open the network tab in your browser tools and convert something: there is no upload request to see.
Transparency handled properly
A PNG with transparency keeps it. One without is encoded as a photograph instead, which is far smaller, and the choice is made by sampling the actual pixels rather than trusting the file extension.
How to use this tool
Drop your PNG files onto the box at the top, or click it to browse. Each one becomes a page, in the order the thumbnails show, and you can drag a thumbnail onto another to move it.
The background setting is the one that matters most here, because PNG is the format people use precisely when they need transparency. Transparent keeps it, any colour fills it in.
The preview redraws as you change the paper, margin or fill, with a dashed line showing where the margin sits. Check the page you care about before you download rather than after.
Transparency is a decision, not a default
PNG carries an alpha channel: every pixel has an opacity as well as a colour. That is why people reach for it for logos, screenshots with rounded corners, diagrams meant to sit on a coloured page.
PDF supports transparency too, so nothing forces you to throw it away. Keep it and your logo will float over whatever is behind it, which is right for something being placed into another document. Fill it and you have decided what sits behind, which is right for something being printed or sent to someone who will print it.
The reason to think about it at all is that transparent does not mean white. It means nothing, and nothing takes on the colour of whatever it lands on. On white paper that looks like white and everyone is happy. On a coloured letterhead, or pasted into a slide with a dark theme, the same file suddenly has a hole in it. Choosing a solid background is how you stop that being a surprise.
Why the tool treats transparent and opaque PNGs differently
A PNG with an alpha channel is embedded as PNG, untouched. It is a lossless format and re-encoding it would both destroy the transparency and make it worse, so the quality slider does nothing to those images.
A PNG with no transparency gets re-encoded as JPEG at the quality you choose, because for photographic content that is dramatically smaller with no visible difference. A screenshot of a webpage is a borderline case: it is flat colour and sharp text, which JPEG handles badly, so if you are converting screenshots turn the quality up to ninety or above and the artefacts around the text disappear.
This is worth knowing because it explains the common complaint that a PNG looks fuzzy after conversion. It is not the conversion, it is JPEG compression applied to exactly the kind of content JPEG is worst at.
A worked check you can repeat
Take a 3000 by 2000 pixel PNG onto A4 portrait with a 10 mm margin, set to Whole image.
A4 is 595.28 by 841.89 points. The margin is 10 times 72 divided by 25.4, which is 28.35 points a side, leaving a printable box of 538.59 by 785.20. The image aspect ratio is 1.5 and the box is 0.686, so width is the limiting dimension and the scale is 538.59 divided by 3000, or 0.17953.
The picture lands 538.59 wide and 359.06 tall, filling the width exactly and centred vertically with 213.07 points above and below. The effective resolution is 3000 pixels across 7.48 inches, about 401 dpi, comfortably past the print threshold, which is why that image carries no warning badge.
Every figure above was checked against an independent implementation before publishing, along with the page presets against their real millimetre and inch dimensions, orientation switching, the fill and stretch modes, resolution round tripping and margins larger than the paper.
Mistakes that catch people out
Assuming transparent means white. It means nothing at all, and nothing looks like whatever is behind it. Fine on white paper, a hole in your logo on anything else.
Converting screenshots at default quality. JPEG smears sharp black on white edges, which is what text is. Push the quality above ninety for screenshots and interface captures.
Saving photographs as PNG in the first place. Nothing here can undo it, but a photograph as PNG is often many times larger than it needs to be for no visible gain. PNG earns its place on flat colour and sharp edges.
Expecting Whole page to keep the whole image. It covers the page, so anything that does not fit is cut off. Use Whole image unless you specifically want edge to edge.
Turning quality up to fix a soft image. Quality and resolution are different things. If the badge says 73 dpi, the fixes are a smaller page or a bigger original.
Common questions
Is my PNG uploaded anywhere?
No. The images are read by your browser, the PDF is assembled here on the page, and the download comes from your own machine. Nothing crosses the network, so there is nothing on a server to store or delete.
Does the transparency survive?
It does if you pick the transparent background. Choose any colour instead and the see through areas are filled with it. A PDF supports transparency, so this is a real choice rather than a limitation.
Why does my transparent logo look wrong when printed?
Because most printers cannot print nothing. Transparent areas come out as whatever the paper is, which is fine on white and unpredictable elsewhere. For anything going to print, choose a solid background so you decide what sits behind the image.
Will the image lose quality?
A PNG with transparency is kept as PNG, which is lossless, so nothing changes. A PNG without transparency is re-encoded as JPEG at the quality you set, because that produces a far smaller file for photographic content. Turn the quality up if you would rather keep every detail.
Why is my PNG file so large?
PNG compresses without losing anything, which is superb for screenshots, logos and line art with flat colour, and inefficient for photographs. A photograph saved as PNG is often five or ten times larger than the same image as JPEG with no visible difference.
Can I mix PNG with other formats?
Yes. Drop in JPG, WebP, GIF and BMP alongside them and they all become pages in the same document, in whatever order you arrange the thumbnails.
Related PDF tools and reference
Reference: ISO 216, the standard that defines the A series paper sizes used here.