The Base64 image converter for Mac

Drop in a picture and get clean Base64 in the exact format you need. Paste Base64 in and watch the picture reappear. One file or ten thousand — and every byte of it stays on your Mac.

See what's inside

Decoding is free, forever.

Get to know B64.

Three workspaces, one job each. Encode turns pictures into Base64. Decode turns Base64 back into pictures. Batch does either one to a whole folder. All of it native, all of it offline.

Encode

Drop it in.
Get it out.

Drag a photo, a screenshot, an icon or a PDF onto B64 and the Base64 is there before you have let go of the mouse. Then pick the shape you actually need it in — a raw string, a data URI, an <img> tag, a CSS rule or a Markdown reference — and copy it in one click.

How to convert an image to Base64 on Mac

Instant, whatever the size.

A thumbnail and a forty-megapixel photograph both land the moment you drop them. Big files are encoded straight to disk rather than held in memory, so nothing stalls.

Five formats, one menu.

Raw Base64, a data URI, a complete <img> tag, a background-image rule, or a Markdown image reference. Choose above the result and it is rewritten instantly.

Wrapped, if you want it wrapped.

Turn on 64- or 76-column wrapping for tidy, standards-friendly output — 76 is the MIME line length. Wrapping is offered only where line breaks are legal, so you can't produce a broken tag.

Paste to convert.

Copy an image anywhere on your Mac and press ⇧⌘V. There is no intermediate file to save first, and no folder to go hunting through afterwards.

PDFs too, not just pictures.

A signed contract, an invoice or a press kit encodes exactly like an image does, and comes back out of Decode as the same document it went in as.

Huge results stay readable.

A result too long to show comfortably is paged rather than dumped, so scrolling stays smooth — while Copy and Export always take the complete string.

The shape you need it in.

Plain Base64. The raw string and nothing else — for a config file, a JSON field, an API payload or anywhere the wrapper is your job.

Data URI. Prefixed with its real MIME type, ready to paste straight into a browser address bar, an href or a stylesheet.

HTML. A complete <img> tag with the data URI already in src — an image in an email template or a one-file page, with no second request to make.

CSS. A finished background-image rule. Drop it into a stylesheet and the asset travels with it.

Markdown. An inline image reference, so a README or a spec carries its own screenshots instead of linking to somewhere they might not stay.

Decode · Free forever

Paste it.
See it.

Someone sends you a wall of characters and says it's an image. Paste it into B64 and it is one — with its real format, its dimensions and its size shown next to it. Decoding is free, with no purchase and no account, and it stays that way.

How to convert Base64 to an image on Mac

Smart about what you paste.

A raw string, a data URI, or Base64 sitting inside an HTML tag, a CSS rule or a Markdown reference. B64 finds the payload and decodes it — you don't have to trim it out first.

It trusts the bytes.

When a data URI claims one type but the bytes are another, B64 says so and believes the bytes. You find out about a mislabelled payload here rather than three systems downstream.

It decodes as you type.

Not on a button press. Paste a payload and the picture is simply there; paste something that isn't valid Base64 and an inline note tells you so instead of a dialog.

Quick Look it full size.

One keystroke and the decoded image fills the screen at full resolution, exactly as Quick Look does everywhere else on your Mac.

Copy it or keep it.

Put the decoded picture straight on the clipboard for the next app, or save it to disk exactly as it was — the same bytes, the right extension, no re-encoding in between.

Enormous payloads, handled.

A multi-megabyte string is held whole and decoded whole, while the text itself is shown in pages so the window never has to render millions of characters at once.

Batch

A folder in.
A folder out.

Drop in a folder of images and B64 sets up an encode. Drop in a folder of Base64 text files and it sets up a decode. Mix files and folders and it still works it out. Thousands of conversions in a single pass, with your Mac staying responsive throughout.

How to convert a folder of images to Base64 on Mac

It works out the direction.

You never tell it which way to go. Images and PDFs set up an encode, Base64 text files set up a decode, and a folder holding both is sorted out for you.

Nothing is silently dropped.

Anything that isn't a supported image, PDF or Base64 text is reported as skipped, with the reason. A run that quietly loses files is worse than one that refuses them.

Thousands, in one pass.

Scanning and converting stream in as they go, with a progress indicator and a Cancel button that actually stops it. The rest of your Mac carries on as if nothing were happening.

Save it all in one step.

Give the results a folder and B64 creates it and writes everything inside — optionally with a checksum manifest for the whole run. Or save any single result on its own.

Any row, opened up.

Double-click a result to work on it directly in Encode or Decode; right-click to save just that one or reveal it in the Finder. A batch isn't a black box.

Both directions, same window.

The folder of PNGs you encoded this morning and the folder of Base64 a colleague sent you this afternoon go through the same workspace.

The Inspector

The details, when you want them.

Press ⌥⌘I and a panel opens beside your work with the details of whatever is in front of you: name, size, type, MIME, dimensions, character count, size overhead — and a SHA-256 checksum, so you can confirm a file is exactly what it should be. Every value is selectable and copyable.

How to get the SHA-256 checksum of an image on Mac

A checksum in one click.

Of the file you encoded, or of the bytes you decoded. Check a decoded image against the original it came from, or against a checksum somebody sent you.

See what Base64 costs.

Base64 is always about a third larger than the file it encodes. The Inspector shows the character count and the exact overhead, so you know before you paste it into something with a size limit.

Declared versus actual.

For a decoded payload the Inspector shows both the type the data URI claimed and the type the bytes really are. When they disagree, you find out here.

Dimensions and type, always.

Whether you are encoding or decoding, the essentials sit beside the work rather than behind a Get Info window in another app.

Pricing

Free to decode.
Unlock the rest once.

No subscription. One purchase, tied to your Apple Account, on every Mac you own.

Free forever

Decode

No purchase. No account. No time limit.

  • Paste any Base64 — raw, data URI, or wrapped in HTML, CSS or Markdown
  • See the format, dimensions and size straight away
  • Quick Look, Copy Image and Save…
  • The Inspector, including SHA-256 checksums
One-time purchase

Pro

Unlocks encoding and batch conversion, for good.

  • Encode images and PDFs to Base64, in all five output formats
  • Batch — whole folders, either direction, thousands at a time
  • Line wrapping, export to file, and checksum manifests
  • Yours across reinstalls and on every Mac on your Apple Account. Bought the original B64? You're unlocked automatically.

Requires macOS 14.0 or later. Pricing is shown in the Mac App Store in your local currency.

Fair questions.

Decoding is free forever — paste Base64, see the image, copy it or save it, with no purchase and no account. Encoding images to Base64 and converting whole folders in Batch are unlocked with a single one-time purchase. There is no subscription, and the unlock is tied to your Apple Account, so it follows you across reinstalls and onto every Mac you own. Anyone who bought the original paid version of B64 is unlocked automatically.

No. Every conversion happens on your Mac, in the app. Nothing is uploaded, nothing is collected, there are no accounts and no analytics. A screenshot with customer data in it, a signed PDF or an unreleased asset can be converted with exactly the same confidence as a holiday photo, because there is nowhere for it to go.

PNG, JPEG, HEIC, HEIF, GIF, TIFF, BMP, WebP, SVG and PDF — anything macOS itself can read as an image or a document. Encoding is byte-for-byte, so the Base64 you get back is the exact file you put in, and decoding it anywhere else reproduces the original bytes precisely.

Five. Plain Base64 is the raw string. Data URI wraps it as data:image/png;base64,… ready for a browser or a stylesheet. HTML gives you a complete <img> tag. CSS gives you a background-image rule. Markdown gives you an inline image reference for a README or a doc. You pick from a menu above the result, and the output changes the moment you do.

Yes. Paste a raw string, a data URI, an <img src="data:…"> tag, a CSS url("data:…") rule or a Markdown image reference, and B64 finds the Base64 inside it and decodes it. You do not have to trim the payload out by hand first.

Thousands, in a single pass, in either direction — and the window stays responsive while it works. Drop in images to encode them, drop in Base64 text files to decode them, or drop in a folder and let B64 work out which way you are going. Anything that is not a supported image, PDF or Base64 text is listed as skipped rather than silently dropped, so you always know exactly what happened to every file.

Confirming that a file is exactly what it should be. The Inspector computes a SHA-256 of the source you encoded and of the bytes you decoded, so you can check a decoded image against the original it came from, or against a checksum someone sent you. Batch exports can carry a checksum manifest for the whole run.

macOS 14 (Sonoma) or later, on any Mac. It is a native app from the Mac App Store — not a web page in a wrapper — so it launches instantly, works offline, and behaves the way a Mac app should: drag and drop everywhere, Quick Look, keyboard shortcuts, and light and dark mode.

Every image. Both directions.
On your Mac.

B64 — Base64 Image Studio. Free to decode, one purchase to encode, private by design.

Requires macOS 14.0 or later.