Free Online Base64 Decoder – Decode Base64 to Text Instantly
Paste a Base64 string, choose your options, and get the decoded result in one click. Also supports encoding.
What is Base64 Encoding & Decoding?
Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It was designed to safely transmit binary data over channels that only support text — such as email (MIME), JSON payloads, and URLs.
Decoding reverses the process — converting a Base64 string back into the original text or binary data. This tool supports both standard Base64 and URL-safe Base64 (which uses - and _ instead of + and /).
Common Base64 Examples
| Base64 String | Decoded Text | Try It |
|---|---|---|
| SGVsbG8gV29ybGQ= | Hello World | |
| VGhpbmtGb3JV | ThinkForU | |
| eyJuYW1lIjoiSm9obiIsImFnZSI6MzB9 | {"name":"John","age":30} | |
| aHR0cHM6Ly93d3cudGhpbmtmb3J1Lm9yZw== | https://www.thinkforu.org | |
| SGVsbG8g8J+RjQ== | Hello 👍 |
How to Use This Base64 Decoder
Paste your Base64 encoded string into the input box, or click "Load Sample" to try an example.
Enable URL-safe mode, JSON formatting, or whitespace trimming as needed.
Click "Decode" or turn on Live Mode for instant auto-conversion as you type.
Copy the decoded text to clipboard or download it as a .txt file.
Switch between Decode and Encode modes with one click — or swap input/output to re-encode.
Click any "Try" button in the examples table to instantly load and decode a sample string.
Who Uses Base64 Decoding?
Decode Base64-encoded API tokens, JWT payloads, or embedded images in HTML/CSS.
Decode obfuscated payloads, reverse-engineer encoded data in malware analysis.
Decode MIME-encoded email content and attachments that use Base64 encoding.
Decode Base64 images or encoded data from mobile API responses.
Understand how Base64 encoding works in computer science and networking courses.
Decode Kubernetes secrets, environment variables, and configuration files encoded in Base64.
Frequently Asked Questions
Is my data sent to any server?
atob() and btoa() functions combined with the TextEncoder API. Your data never leaves your device. See our Zero Data Storage Policy.What is URL-safe Base64?
+ and / characters which have special meaning in URLs. URL-safe Base64 replaces these with - and _ respectively, making the output safe to use in URLs and filenames without percent-encoding. Enable the "URL-Safe" option when decoding such strings.Why do I get an "Invalid Base64" error?
= makes this so). Common causes of errors: missing padding characters (=), non-Base64 characters in the string, or trying to decode a URL-safe string without enabling the URL-safe option. Try enabling "Trim Whitespace" to remove hidden spaces.What does "Format JSON" do?
Can I decode Base64-encoded images?
data:image/png;base64,...), the raw Base64 string (without the data URI prefix) will be decoded to binary — the output may not be readable as text but can be downloaded as a file.What is the difference between encoding and decoding?
How do I decode a JWT token?
header.payload.signature. The header and payload are Base64url encoded. Copy the middle part (payload), enable "URL-Safe Base64" and "Format JSON", then click Decode to read the token's claims.