Base64 Encoder / Decoder
Base64 is a way of representing text or binary data using only 64 safe ASCII characters, so it can travel through systems designed for plain text. FreeToolsKit's encoder converts text and files to Base64 and decodes Base64 back, handling non-English characters correctly via UTF-8. All conversion happens in your browser — files and text are never uploaded.
Last updated: October 20, 2026
Key takeaways
- Text encoding is UTF-8 safe, so accents, emoji and non-Latin scripts survive the round trip.
- Files can be turned into a full data URI or raw Base64, with an image preview when the file is a picture.
- Decoding validates the input and explains errors instead of producing garbage.
- Base64 grows data by about a third — it is an encoding for transport, not compression or encryption.
How do you encode or decode Base64?
- Choose a tab: Text → Base64, Base64 → Text, or File → Base64.
- Type or paste your text, or pick a file from your device.
- Read the converted result, which appears instantly.
- Press Copy to take the output, or Download to save it as a text file.
- For an image file, check the preview to confirm the data URI renders correctly.
What is the Base64 Encoder / Decoder used for?
- Embedding a small image directly into HTML or CSS as a data URI.
- Encoding credentials or tokens into the format an API's Basic auth header expects.
- Decoding a Base64 string found in a log, email source or JWT payload segment.
- Moving binary data through a JSON field that only accepts text.
- Testing how an application handles encoded input during development.
Frequently asked questions
Is Base64 encryption?
No. Base64 is a reversible encoding that anyone can decode instantly — it protects nothing. Never use it to hide passwords or secrets; use real encryption for anything sensitive.
Why does the output contain “=” signs at the end?
They are padding. Base64 works in fixed-size blocks, and “=” characters fill the final block when the input length is not an exact multiple of three bytes. One or two padding characters are normal and required.
Why does Base64 make files bigger?
Base64 represents every 3 bytes of data with 4 characters, so the output is about 33% larger than the input. That overhead is the price of making binary data safe for text-only systems.
Why did decoding fail?
Decoding fails when the input contains characters outside the Base64 alphabet, has missing padding, or includes stray whitespace from a copy-paste. The tool reports an error rather than guessing — trim the input and try again.
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