What is Base64 encoding?

Base64 is a method of encoding binary data into printable ASCII text using 64 characters (A-Z, a-z, 0-9, +, /). It's used when you need to transmit binary data through text-only channels like email, URLs, JSON, or HTML. The encoded output is always ~33% larger than the original.

How do I decode Base64 to text?

Paste your Base64-encoded string into our decoder and it instantly converts it back to readable text. Our tool auto-detects whether your input is Base64 or plain text. It handles standard Base64, URL-safe Base64, and Base64 with or without padding.

What is URL-safe Base64?

URL-safe Base64 replaces the + and / characters (which have special meaning in URLs) with - and _. It also typically omits the = padding. This variant is used in JWTs, URL parameters, and filenames. Our tool supports both standard and URL-safe Base64.

Is Base64 the same as encryption?

No! Base64 is encoding, not encryption. Anyone can decode Base64 — there's no secret key involved. Never use Base64 to protect sensitive data. It's designed for data transport (embedding binary in text), not security. For security, use proper encryption (AES, RSA) or hashing (SHA-256).

Why does Base64 make data larger?

Base64 encodes 3 bytes of input as 4 characters of output (24 bits → 4 × 6-bit groups). This means the output is always 4/3 (~133%) the size of the input, plus padding. For a 1 MB file, the Base64 version is about 1.37 MB. This size increase is the tradeoff for ASCII compatibility.

Does Base64 support Unicode and UTF-8?

Yes — our Base64 encoder first converts text to UTF-8 bytes, then encodes those bytes to Base64. This correctly handles all Unicode characters including emojis, CJK characters, and accented letters. When decoding, the Base64 is decoded to bytes then interpreted as UTF-8.

Base64 Encoder/Decoder

Our Base64 encoder decoder converts text to Base64 encoding and back in real-time. Paste any text and get the Base64-encoded version, or paste Base64 to decode it back to readable text. Supports standard Base64 (RFC 4648) and URL-safe Base64. Handles UTF-8 characters, JSON strings, and large text. All processing is client-side — your data never leaves your browser.

star 4.9 (1,600 ratings)

calendar_today Updated: April 2026

auto_awesome AI Insights AI

New

URL-safe

Text to Encode

0 characters

Base64 Output

0 characters

auto_awesome AI Analysis

Base64 Analysis:

Mode: Encode text → Base64
Output size: ~33% larger than input

Tip: Base64 is encoding, not encryption. Never use it for security.

lightbulb Tips

•Base64 output is always ~33% larger than input
•URL-safe Base64 uses - and _ instead of + and /
•Base64 is encoding, NOT encryption
•3 input bytes = 4 Base64 characters

How to Use This Calculator

swap_horiz

Choose Mode

Select Encode to convert text to Base64, or Decode to convert Base64 back to text.

text_fields

Enter Input

Type or paste your text (for encoding) or Base64 string (for decoding).

content_copy

Get Result

The result appears instantly. Click Copy to copy to clipboard.

link

URL-Safe Option

Toggle URL-safe mode to use - and _ instead of + and / for URL-compatible output.

The Formula

Base64 encoding converts binary data to printable ASCII text by splitting input bytes into 6-bit groups and mapping each group to one of 64 characters (A-Z, a-z, 0-9, +, /). Since 3 bytes (24 bits) map to 4 Base64 characters, the output is ~33% larger than the input. Padding (=) is added if the input length isn't a multiple of 3.

Base64 = encode(input bytes) → 6-bit groups → A-Za-z0-9+/ alphabet

lightbulb Variables Explained

input bytes UTF-8 encoded bytes of the input text
6-bit groups Input split into 6-bit chunks (vs 8-bit bytes)
A-Za-z0-9+/ 64 printable ASCII characters used in the encoding alphabet
= (padding) Padding character added to make output length a multiple of 4

tips_and_updates Pro Tips

Base64 output is always ~33% larger than the input

URL-safe Base64 replaces + with - and / with _ (useful for URLs and filenames)

Base64 is encoding, NOT encryption — anyone can decode it, so never use it for security

Use Base64 to embed small images in HTML/CSS via data URIs

JSON Web Tokens (JWT) use URL-safe Base64 encoding for header and payload

The = padding at the end can be safely removed for URL-safe Base64

Base64 handles binary data — it's how email attachments are transmitted

Encode & Decode Base64 Online

Our free Base64 encoder decoder converts text to Base64 and back instantly. Supports standard and URL-safe Base64, UTF-8 characters, and large text. All processing happens in your browser — your data stays private.

Base64 Encoder - Text to Base64

Convert any text to Base64 encoding instantly. Our encoder handles UTF-8 characters, JSON strings, HTML, and any text input. Copy the Base64 output for use in APIs, data URIs, email encoding, or configuration files.

Base64 Decoder - Base64 to Text

Decode any Base64 string back to readable text. Paste Base64-encoded content and see the original text instantly. Handles standard Base64, URL-safe Base64, and Base64 with or without padding characters.

Frequently Asked Questions

Related Tools

View all General View all arrow_forward

widgets