Base64 Decode Online — Free, Instant, No Signup

Paste a Base64 string, get readable text back instantly. No signup, no file upload, no server processing. The decoding happens right in your browser.

Decode Base64 in 3 Steps

1. Open the Base64 Encoder/Decoder
2. Paste your Base64 string into the input box
3. Click Decode and copy the result

Supports full UTF-8, so accented characters, CJK text, and emoji decode correctly.

What Base64 Looks Like

Base64 encoded text is always a string of letters, numbers, plus signs, slashes, and optional trailing equals signs. Examples:

Base64	Decoded Text
SGVsbG8gV29ybGQ=	Hello World
dGVzdEBleGFtcGxlLmNvbQ==	[email protected]
eyJhbGciOiJIUzI1NiJ9	{"alg":"HS256"} (JWT header)
cGFzc3dvcmQxMjM=	password123

If you see a string that looks like random characters but only contains A-Z, a-z, 0-9, +, /, and = padding, it is almost certainly Base64.

When You Need to Decode Base64

Reading API Responses

Many APIs return data in Base64. OAuth tokens, webhook payloads, email attachments in MIME format. You receive a wall of characters and need to see what is inside. Paste it into the decoder, get the original content.

Debugging JWT Tokens

JSON Web Tokens (JWTs) are three Base64-encoded segments separated by dots. The first segment is the header, the second is the payload (claims). Decode the middle segment to see the user ID, expiration time, and permissions without needing a dedicated JWT tool. For a full JWT breakdown, the JWT Decoder parses all three segments automatically.

Reading Kubernetes Secrets

Kubernetes stores secret values as Base64 strings. When you run kubectl get secret my-secret -o yaml, the values are encoded. Decode them to verify the actual password, connection string, or API key that your pods are using.

Inspecting Email Source

Email bodies and attachments are often Base64-encoded in MIME format. When debugging email delivery issues, you may need to decode the raw content to see what was actually sent.

Base64 Decode in the Terminal

If you prefer the command line:

• Linux/Mac: echo "SGVsbG8=" | base64 -d
• Windows PowerShell: [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String("SGVsbG8="))
• Python: import base64; print(base64.b64decode("SGVsbG8=").decode())

These work but are verbose. For a quick check during debugging, pasting into the browser tool is faster than remembering the syntax.

Common Decoding Errors

• Output is gibberish: The original content was binary (image, PDF, ZIP), not text. You cannot view binary as readable text.
• Invalid Base64 error: The string contains characters outside the Base64 alphabet, or has incorrect padding. Check for stray whitespace or line breaks.
• Partial decode: The string may be URL-safe Base64 (using - and _ instead of + and /). Some tools handle this automatically, others do not.

Privacy Matters for Decoding

When you decode Base64 strings containing passwords, tokens, or personal data, you want certainty that the data stays on your device. Our tool runs entirely in the browser. The decode function uses built-in browser APIs. No network requests are made during the decode operation. Your sensitive data never touches a server.

Related tools: URL Encoder/Decoder for percent-encoding, HTML Entity Encoder for special characters, Hash Generator for creating checksums.