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PNG to Base64 Converter: Encode PNG as a Data URI

Encode a PNG into a Base64 data URI in your browser. Paste it into HTML, CSS, or JS to inline small icons. No upload, one-click copy, lossless.

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How It Works

Inlining a small PNG as a Base64 data URI removes one HTTP request: the image bytes ride inside your HTML, CSS, or JS instead of sitting in a separate file the browser has to go fetch. This tool reads your PNG locally, encodes it into a `data:image/png;base64,...` string, and drops it next to a one-click Copy button. The file never leaves your machine. The encoding step itself is lossless. Every pixel and the full alpha channel survive, so transparent icons stay transparent. Base64 represents 3 bytes of binary as 4 ASCII characters, which is why the string runs roughly a third larger than the source file. That overhead is a fair trade for a 2 KB icon and a poor one for a 200 KB image, where you also forfeit browser caching and bloat the stylesheet that ships it. One thing worth knowing: the output is a freshly re-encoded PNG, not a byte-for-byte copy. Your PNG is decoded, redrawn on a canvas, and re-encoded, so ancillary chunks like embedded ICC profiles and text metadata are dropped, and 16-bit images are flattened to 8-bit per channel. The pixels you see are identical, but the resulting string can differ in length from the original. Paste the copied URI into an `<img src>`, a CSS `background-image: url(...)`, or a JS string and it renders with no separate request.

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Key Features

  • No file uploads required - works offline
  • 100% privacy focused - client-side processing
  • Browser powered - no software installation
  • Fast processing - WebAssembly technology
  • Free forever - no premium accounts

Supported File Formats

.png

Output Format: Base64

Technical Specifications

input Format PNG (Portable Network Graphics, with or without alpha; 16-bit input is downsampled to 8-bit)
output Format Base64 data URI string (data:image/png;base64,...)
compression Type Lossless text encoding of a re-encoded PNG; no quality loss in the encoding step
quality Retention Pixels and alpha channel preserved; metadata chunks stripped, 16-bit flattened to 8-bit
color Space Support RGB and RGBA (8-bit per channel); embedded ICC color profiles are not carried over
max Resolution Limited only by your device's memory
processing Time Instant, runs in your browser

Key Benefits

  • Drops a separate HTTP request for small images
  • Lossless encoding: pixels and full transparency preserved
  • One-click Copy gives a ready-to-paste data:image/png;base64 URI
  • Runs 100% in your browser, no file ever uploaded
  • Works as-is in HTML, CSS url(), and JavaScript strings
  • No sign-up, no watermark, no per-file limit beyond your memory

Common Use Cases

  • Inlining UI icons and small logos into a CSS stylesheet
  • Embedding a placeholder or sprite directly in HTML markup
  • Bundling assets into a single-file HTML page or web component
  • Hardcoding a small graphic into a JavaScript or framework component
  • Storing a tiny image as a text field in JSON or a database
  • Cutting an extra request for above-the-fold icons that block render

Pro Tips

  • Keep it to small assets; the ~33% overhead and lost caching hurt large images
  • Copy the full string including the data:image/png;base64, prefix or it won't render
  • For a repeating CSS background, an inlined icon avoids a flash before it loads
  • Don't inline images reused site-wide; you forfeit the shared browser cache
  • For a flat-color shape that just needs transparency, an inline SVG is usually far smaller than a PNG data URI
  • Test data URIs in email carefully; Outlook and Gmail web often block them

Frequently Asked Questions

Paste the whole string, including the data:image/png;base64, prefix, into a url(): background-image: url(data:image/png;base64,iVBORw0KGgo...). The same string works unchanged in an HTML <img src="..."> attribute or as a JS string. CSS needs no special quoting, though wrapping the value in quotes is harmless and some linters prefer it.
The Base64 step is lossless: it is a text encoding of the binary, so pixels and the alpha channel are preserved exactly. The one nuance is that this tool re-encodes the PNG through a canvas, which strips metadata like ICC profiles and flattens 16-bit images to 8-bit. For ordinary 8-bit web graphics that makes no visible difference.
Base64 maps every 3 bytes to 4 ASCII characters, an inherent ~33% increase, plus a little padding. For a small icon that is a good trade to save an HTTP request. For larger images the overhead, combined with losing browser caching, usually makes a normal linked file load faster.
Inline small, static assets: UI icons, sprites, a tiny logo, or a placeholder that would otherwise be an extra render-blocking request. Don't inline anything large or anything reused across many pages. A linked file is cached once and shared everywhere, while an inlined one is re-downloaded with every page that contains it.
No. The encoding runs entirely in your browser in JavaScript. The PNG never leaves your device, so it's safe for internal assets, screenshots, or anything you wouldn't want to send to a third-party service.
Support is inconsistent. Apple Mail and many mobile clients render data URIs, but several Outlook versions and Gmail's web client strip or block them. For HTML email, host the image and link it with an absolute URL instead of inlining.
Any Base64 decoder reverses it cleanly, since the encoding loses no information. On this site the base64-to-image and base64-to-jpg tools take a data URI or raw string and hand back a downloadable file.
You're limited by your device's memory, with a 100 MB cap in the uploader. In practice anything past a few dozen KB is a weak candidate for inlining, so keep this for small graphics and link the rest as normal files.