Base64 writes binary data with 64 printable characters: A to Z, a to z, 0 to 9, + and /, with = as padding. It dates from the PEM mail standard of 1987, was fixed in MIME in 1993 and is specified in RFC 4648. It exists so that bytes can travel through systems built for text, such as email and JSON.

How does Base64 encoding work?

Three bytes are 24 bits, split into four groups of six bits, each written as one of the 64 characters. The output is a third larger than the input. When the input isn't a multiple of three bytes, the last group is padded with one or two = characters so the length is a multiple of four.

What is Base64 used for?

Email attachments (MIME), data URLs in HTML and CSS, JSON Web Tokens, HTTP Basic authentication headers, images inlined in stylesheets, binary fields in JSON and XML, and the SSH and PEM key files on every developer's machine.

Not the standard alphabet: + and / have meanings in a URL and = is reserved, so they have to be percent-encoded. The URL-safe variant from RFC 4648 §5 swaps them for - and _ and usually drops the padding; JWTs and most web APIs use it. The encoder here offers both.

How does Base64 compare to the other encodings?

It is the default for a reason: a third larger than the bytes, where hex doubles them and Base85 adds a quarter; built into every language and browser (btoa, atob, Buffer); and understood by every protocol. Pick Base32 when case can't be trusted, Base58 for things people copy by hand, Base85 only where PDF or PostScript asks for it.

Can Base64 be used for encryption?

No. Base64 is an encoding, not encryption: it changes how bytes are written, not who can read them, and anyone can decode it with no key. Encrypt first (AES, age, a library's sealed box) when the content needs protecting, then encode the ciphertext if it has to travel as text.

How do I turn Base64 back into a file?

Paste the Base64 into the input, or drop a text file that holds it. The tool decodes the bytes, says what they look like and how many there are, and shows the image when they are one. Check the file name, which is guessed from the bytes, and press Download.

How does the tool know the file type?

From the first bytes. Most formats start with a signature, 89 50 4E 47 for PNG, %PDF for PDF, PK for ZIP, and the tool knows the common images, documents, archives, fonts and media, and tells text from the rest. It is a guess for the file name only; if you know what the bytes are, rename the file and it downloads under that name.

Why doesn't the downloaded file open?

Usually the Base64 was cut short or carries something extra. Copy the whole value, including its end; leave out quotes and commas from the surrounding code; a data URL's data:…;base64, prefix is fine, the tool drops it. If the status line says the bytes look like text when you expected an image, the value wasn't the file's Base64 to begin with.

Is my text uploaded anywhere?

Nothing leaves your browser. The text is read into memory on your machine and the encoding is computed there, in plain JavaScript; the page makes no request with it. Load the page, go offline and it keeps working.

Base64 to file.

Paste Base64 and get the file back. The tool decodes the bytes in your browser, tells you what they look like, shows an image when it is one, and downloads under the name you choose.64 characters+33% size4:3 characters to bytes0 bytes uploaded

Get Pro Get the file

Add shadcn.io to your AI agent. · Pro It installs blocks, icons and templates in your design system from a prompt, with Pro.

Set up MCP

Loading the tool…

Need the UI around it? With Pro, your AI agent builds the form, the result card and the rest of the page from a prompt.

Get Pro

How it works

3 steps, no account. It runs in your browser and nothing is uploaded.

Paste the Base64
Paste the Base64, or drop a text file that holds it; the bytes are decoded as you type.
See what the bytes are
The result says how many bytes there are and what format they start like, with a preview when it's an image.
Name the file and download it
The name is guessed from the bytes; change it if you know better, then press Download.

Nearby in the encoders and decoders. Every one free, in the browser.

Pricing

Build it with Pro

The tool is free. Pro adds 6,000+ blocks, premium templates and the MCP server, so your AI editor builds the product around it.

See full pricing

4.9/5 out of 5 · 150+ reviewsfrom 150+ founders and developers.

Billing

Billed once a year in USD. Cancel anytime.

Yearly-33%MonthlyLifetimePay once

How many people can use the license.
Client work, SaaS products and anything you charge for.
Production-ready React sections: hero, pricing, features, dashboards and more.
Complete multi-page sites you can ship as they are.
React icons from every major library, installable with one command.
Presets that restyle every block, in light and dark.
Lets your AI editor search, preview and install blocks for you.
Priority requests are answered first.

Individual

For personal projects & open source

$32instead of $49/mo

$389 billed yearly

Seats: 1 seat
Commercial use: Personal & open source only
Pro blocks: 6,000+ blocks
Templates: All 14 templates
React icons: 294k+ icons
Themes: All 59 themes
MCP server: Basic usage
Support: Standard

Team

Organization

For companies with larger teams

$132instead of $199/mo

$1,589 billed yearly

Seats: Unlimited seats
Commercial use: Included
Pro blocks: 6,000+ blocks
Templates: All 14 templates
React icons: 294k+ icons
Themes: All 59 themes
MCP server: Unlimited usage
Support: Priority

Billed once a year in USD. Cancel anytime.

Individual

For personal projects & open source

$32instead of $49/mo

$389 billed yearly

How many people can use the license.Seats: 1 seat
Client work, SaaS products and anything you charge for.Commercial use: Personal & open source only
Production-ready React sections: hero, pricing, features, dashboards and more.Pro blocks: 6,000+ blocks
Complete multi-page sites you can ship as they are.Templates: All 14 templates
React icons from every major library, installable with one command.React icons: 294k+ icons
Presets that restyle every block, in light and dark.Themes: All 59 themes
Lets your AI editor search, preview and install blocks for you.MCP server: Basic usage
Priority requests are answered first.Support: Standard

Team

Organization

For companies with larger teams

$132instead of $199/mo

$1,589 billed yearly

Everything in Team, plus

How many people can use the license.Seats: Unlimited seats
Lets your AI editor search, preview and install blocks for you.MCP server: Unlimited usage

Secure checkout via Stripe
Code lives in your repo
Keep what you've shipped if you cancel
License terms

Questions and answers

Before you trust the result: what to know about the format, the limits and your data.

Build the product around it

Every block, template and icon, installed by your AI agent in your theme. The tools stay free.

Get Pro

Cancel anytimeKeep what you've shipped if you cancel

Explore UI

Popular

Frameworks

Built On

Explore Blocks

Marketing

Application

Explore Charts

Popular

Frameworks

Explore Examples

More Galleries

Explore Icons

More Libraries

Browse

Explore Templates

Categories

Community

Explore Design Systems

Categories

More

Explore Tools

Categories

Explore MCP

Set Up In

Help

Explore Pro

Resources

Legal

Base64 to file.

Base64 to file.

How it works

Paste the Base64

See what the bytes are

Name the file and download it

Related tools

Build it with Pro

Individual

Team

Organization

Individual

Team

Organization

Questions and answers

What is Base64?

How does Base64 encoding work?

What is Base64 used for?

Is Base64 URL-safe?

How does Base64 compare to the other encodings?

Can Base64 be used for encryption?

How do I turn Base64 back into a file?

How does the tool know the file type?

Why doesn't the downloaded file open?

Is my text uploaded anywhere?

Build the product around it