How to use Base64 Encoder / Decoder
To encode text to Base64: paste or type your plain text into the Input field on the left, make sure the Encode mode is selected (the blue pill button at the top), then click the Encode button. The Base64-encoded string appears instantly in the Output field on the right. Click Copy to send the result to your clipboard — ready to paste into an API request, email header, data URI, or configuration file.
To decode Base64 back to plain text: click the Decode button to switch modes, paste your Base64 string into the Input field, then click Decode. The original text appears in the Output field. If the input is not valid Base64 — for example it contains invalid characters or incorrect padding — the tool will display an error message below the output. Click Clear at any time to reset both fields and start over.
Why use our Base64 Encoder / Decoder?
- 100% browser-based — your text and data never leave your device or touch any server
- Handles full UTF-8 and Unicode input correctly, including emoji, CJK characters, and accented letters
- Encode and decode in the same tool — no need to switch between separate sites
- Instant results with no page reload — output appears as soon as you click the button
- Completely free with no rate limits, no account, and no installation required
- Safe for sensitive payloads — API tokens, credentials, and private strings stay local
Frequently Asked Questions
What is Base64 encoding and what is it used for?
Base64 is a binary-to-text encoding scheme that represents binary data using only 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It is widely used to safely embed binary content — such as images, files, or binary API payloads — inside text-only formats like JSON, XML, HTML, CSS data URIs, and email (MIME). Because Base64 uses only printable characters, it avoids issues with special characters, null bytes, or control characters that would break text-based protocols.
Source: RFC 4648 — The Base16, Base32, and Base64 Data Encodings
Does Base64 encoding encrypt my data?
No. Base64 is an encoding scheme, not an encryption algorithm. It simply converts binary data into a text-safe format. Anyone who has your Base64 string can decode it back to the original content instantly — no key or password is needed. Never use Base64 as a security measure. If you need to protect sensitive data, use proper encryption algorithms such as AES before encoding the ciphertext with Base64.
Why does my Base64 output sometimes end with '=' or '=='?
Base64 encodes every 3 bytes of input into 4 characters. When the input length is not a multiple of 3, the encoder adds padding characters ('=') at the end to make the total output length a multiple of 4. One '=' means the last group had 2 bytes; two '==' means it had 1 byte. The padding is required by the Base64 specification and is automatically handled by decoders — you should include it when decoding.
Is it safe to paste sensitive data into this tool?
Yes. This encoder runs entirely inside your browser using JavaScript's native btoa() and atob() APIs — no network request is made at any point. Your input is never transmitted to any server, never stored, and never logged. You can safely encode or decode API keys, authentication tokens, private configuration values, or any other sensitive strings. Closing or refreshing the page clears all input and output immediately.
What is the difference between standard Base64 and Base64url?
Standard Base64 uses '+' and '/' as the 62nd and 63rd characters, which are not safe to use directly in URLs or filenames because browsers and servers interpret them as special characters. Base64url is a URL-safe variant that replaces '+' with '-' and '/' with '_', and often omits the trailing '=' padding. Base64url is used in JWT tokens, OAuth codes, and file names. If you need to include a Base64 string in a URL query parameter, either switch to Base64url or URL-encode the standard Base64 output.