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Base64 Decoder

Decode standard Base64 online to UTF-8 text or inspect decoded binary bytes as hexadecimal.

Strict standard Base64 validation Accept wrapped input and omitted trailing padding Decode to UTF-8 text Inspect binary output as hexadecimal bytes
Whitespace and omitted trailing padding are accepted. Invalid alphabet, misplaced padding, or non-UTF-8 bytes are reported clearly in text mode.
INPUT Base64 value to decode *
0 chars0 words0 lines
Paste standard Base64 that should decode to readable UTF-8 text. Example: SGVsbG8sIFRvb2xIdWIh

Tool settings

Ctrl / ⌘ + Enter
Decoded Base64 Strictly decoded standard Base64 with missing trailing padding accepted.
About the tool

What Base64 Decoder does

Base64 Decoder converts standard Base64 back into its original bytes. Choose UTF-8 text for readable content or Hex bytes when the payload is binary.

The decoder accepts whitespace from wrapped Base64 and can restore omitted trailing padding. It rejects invalid alphabet characters, misplaced padding and malformed lengths rather than silently producing questionable output.

Base64 is not encryption. Decoded data can contain secrets, tokens or private information, so treat the output according to its real sensitivity.

How to use

  1. Paste Base64. Wrapped values are accepted.
  2. Select output. Use UTF-8 text for readable content or Hex bytes for binary data.
  3. Decode. The input is validated before output is returned.
  4. Inspect errors. Invalid alphabet, length or padding is reported clearly.
  5. Verify. Re-encode the result when exact round-trip behavior matters.
Built for the task

Why use Base64 Decoder?

Focused controls, predictable output, and a workflow designed around this exact transformation.

01

Strict validation

Malformed alphabet and padding are rejected instead of being silently ignored.

02

Text or hex output

Readable UTF-8 and binary byte inspection are both supported.

03

Wrapped input support

Whitespace and common omitted trailing padding are handled.

04

Clear binary warning

Non-UTF-8 output is reported and can be inspected as hex bytes.

Useful answers

Questions about Base64 Decoder

Practical details about input, output, privacy, limits, and the best way to use this tool.

01 Can this decode Base64 without = padding?

Yes. Missing trailing padding is restored when the remaining Base64 length is valid.

02 Does it ignore spaces and line breaks?

Yes. Whitespace is removed before validation so wrapped Base64 can be decoded.

03 Why does UTF-8 mode reject my Base64?

The Base64 may be valid but decode to binary bytes that are not valid UTF-8. Choose Hex bytes to inspect that payload.

04 Does this decode Base64URL?

Use the Base64URL Decoder for values that use - and _ instead of + and /.

05 Is decoded Base64 trustworthy?

No. Decoding only reveals bytes; it does not verify origin, authenticity or safety.

Learn Base64

Read the complete Base64 Guide

Understand Base64 encoding, decoding, Base64URL, UTF-8 input, padding, data URLs, and frequent integration mistakes.

  • Encoding and decoding
  • Base64URL and padding
  • APIs, files, and data URLs
Read guide Practical explanations and examples
Continue this workflow

Related tools for Base64 Decoder

Open the next relevant utility without returning to the main directory.

Related toolBase64 Encoder Related toolURL Encoder Related toolURL Decoder Related toolURL Parser Related toolQuery String Parser Related toolCertificate Decoder Related toolJWT Decoder Related toolChecksum Calculator

Examples

Decode readable text

UTF-8 text mode returns the original readable value.

Base64 input 
SGVsbG8sIFRyZXhtaSE=
Decoded text 
Hello, Trexmi!

Decode unpadded JSON

Valid omitted trailing padding is restored before decoding.

Base64 input 
eyJhY3RpdmUiOnRydWV9
Decoded text 
{"active":true}

Inspect binary bytes

Hex mode displays bytes that are not valid UTF-8 text.

Base64 input 
AP+AQQ==
Decoded text 
00 FF 80 41

Base64 decoding examples

Decode plain English text

Input: SGVsbG8sIFRyZXhtaSE=
Mode: UTF-8 text
Output: Hello, Trexmi!

Decode Ukrainian UTF-8 text

Input: 0J/RgNC40LLRltGCLCBUcmV4bWkh
Mode: UTF-8 text
Output: Привіт, Trexmi!

Decode a JSON payload

Input: eyJhY3RpdmUiOnRydWV9
Mode: UTF-8 text
Output: {"active":true}

Inspect binary bytes

Input: AP+AQQ==
Mode: Hex bytes
Output: 00 FF 80 41

Readable text versus binary output

Base64 represents bytes, not characters. UTF-8 mode succeeds only when those bytes form valid UTF-8 text. Images, archives, compressed data, and encrypted payloads should be inspected in Hex bytes mode rather than forced into unreadable text.

Whitespace from wrapped Base64 is ignored. One or two omitted trailing padding characters can be restored when the remaining length is valid. These conveniences do not make Base64URL input valid standard Base64: URL-safe data uses a different alphabet.

Invalid alphabet, length, and padding

The decoder rejects characters outside the standard alphabet, padding in the middle of a value, more than two padding characters, impossible lengths, and noncanonical encodings. A failure in UTF-8 mode may mean the decoded data is binary; retry with Hex bytes before concluding that the input is malformed.

Related Trexmi tools

Use Base64 Encoder for the reverse operation, URL Decoder when the Base64 value is percent-encoded inside a URL, or JSON Formatter after decoding JSON text.

Reference

Standard Base64 is defined in RFC 4648.