Base64 takes three 8-bit bytes (24 bits) and re-slices them into four 6-bit groups, each mapped to one of 64 printable characters — which is why encoded output is about 33% larger. Trailing = signs pad the final group. Everything here runs in your browser; nothing is uploaded.
How to use the Base64 converter
Pick Encode to turn readable text into Base64, or Decode to turn Base64 back into text. The result updates as you type, and the Copy button puts it on your clipboard. Use Swap to feed the output straight back as the next input. Turn on URL-safe when the value goes into a URL, filename or JWT, so +// become -/_ and padding is dropped.
When you would reach for Base64
Inlining a small image or font as a data: URI, attaching files to email (MIME), embedding binary blobs in JSON or YAML config, Basic-auth HTTP headers, and the header/payload of a JWT are all Base64. It keeps binary data intact across channels that expect plain text — but remember it offers no privacy, so it is never a substitute for encryption.
🔐 Private by design: this tool runs 100% in your browser — nothing you paste is uploaded. For network, server and security projects, talk to Servnet, a UK IT partner since 2001.
Base64 — common questions
What is Base64 encoding used for?
Base64 represents binary data using 64 printable ASCII characters, so it can travel safely through systems built for text — embedding images in HTML/CSS (data URIs), encoding email attachments (MIME), storing binary in JSON or XML, and carrying credentials in HTTP headers. It is an encoding, not encryption: anyone can decode it.
Is Base64 secure or encrypted?
No. Base64 is reversible by design and provides no confidentiality whatsoever — it only changes the representation of data, not its secrecy. Never use Base64 to "hide" passwords or secrets; use proper encryption or hashing for that.
What is the difference between Base64 and Base64URL?
Standard Base64 uses + and / and pads with =. Those characters are unsafe in URLs and filenames, so Base64URL replaces + with -, / with _ and usually drops the padding. Toggle "URL-safe" above to switch. JWTs, for example, use Base64URL.
Why is my encoded text about a third larger?
Base64 turns every 3 bytes (24 bits) into 4 characters (each carrying 6 bits), so output grows by roughly 33%. That overhead is the trade-off for making binary data text-safe.
Does this tool handle emoji and accented characters?
Yes. Text is encoded as UTF-8 first, so emoji, accents and any Unicode character round-trip correctly — unlike naïve encoders that only handle ASCII.
Is my data uploaded anywhere?
No. All encoding and decoding runs locally in your browser using JavaScript. Nothing you type is sent to a server, which makes it safe for sensitive strings.