Does this tool work entirely in my browser?

Yes. Encoding and decoding both use built-in browser APIs (btoa/atob plus a small UTF-8 wrapper). Nothing is uploaded — your input, including sensitive content like JWTs, API keys, or Basic Auth credentials, never leaves your device. No logging, no analytics on the content.

What's the difference between Standard Base64 and URL-safe Base64?

Standard Base64 (RFC 4648 §4) uses A-Z, a-z, 0-9, +, /, and = for padding. URL-safe Base64url (RFC 4648 §5) substitutes - for + and _ for / so the result is safe inside URLs without further encoding, and typically omits the = padding. JWTs, OAuth tokens, and many web standards use the URL-safe variant.

Can this tool encode files or images?

No. This tool is text-only. To convert an image or binary file to a Base64 data URI, paste a small script into your browser's DevTools console — for example: `const b = await file.arrayBuffer(); const s = btoa(String.fromCharCode(...new Uint8Array(b))); console.log('data:image/png;base64,' + s);` — or use a command-line tool like `base64 < file.png`. The text input here accepts UTF-8 text up to several MB but will not parse binary file content.

Why does my decoded Base64 look like garbled characters?

If the original encoded content was binary (an image, PDF, executable, or other non-text data), the decoded output cannot be displayed as readable text — you're seeing UTF-8 attempting to interpret raw bytes. This usually means the source isn't text to begin with, not that decoding failed. To recover the actual binary file, you'd need a binary-aware tool.

Why is my JWT failing to decode?

Two common reasons: (1) you pasted only part of the JWT — make sure you're decoding ONE segment at a time (split the token on the dots), not the whole thing. (2) JWTs use URL-safe Base64 — switch the mode toggle to URL-safe and try again. For full JWT inspection with signature verification, use our dedicated JWT Decoder.

Is Base64 a form of encryption or compression?

Neither. Base64 is an encoding — a deterministic, reversible mapping that lets binary data travel safely through text-only channels (JSON, XML, HTTP headers, email). It does not protect content from being read (encoding ≠ encryption) and it actually makes data larger, not smaller (encoding ≠ compression).

Why is the Base64 output longer than the input?

Base64 uses 6 bits per character to represent 8-bit binary, so every 3 input bytes produce 4 output characters — about a 33% increase. There's no way to avoid this overhead with Base64; if size matters and the channel allows binary, send the raw bytes instead.

What's a Base64 data URI?

A data URI embeds content directly in a URL using the syntax data:[mime-type];base64, . Example: data:image/png;base64,iVBORw0KGgo... You can use this in CSS (background-image), HTML (img src), or anywhere a URL is expected. Best for tiny assets — larger ones bloat HTML/CSS files and hurt cache efficiency.

Can I decode a Base64 string that was copied with extra newlines?

Yes. The tool ignores whitespace inside the input — line breaks, spaces, and tabs are stripped before decoding. PEM-style content (which wraps at 64-76 chars per line) and shell-copied output paste cleanly.

Why does the "likely Base64" indicator say No on valid text?

The detector checks both the character set (only Base64 alphabet allowed, plus padding) and the length (a multiple of 4 for standard Base64). Plain English text usually contains characters outside the Base64 alphabet (spaces, punctuation, etc.) and so is correctly flagged as not-Base64. This is a feature — it prevents the decoder from trying to interpret arbitrary text as Base64 and producing nonsense.

ConversoresParte de Conversores →

Codificador / Decodificador Base64

Q: Why does my decoded Base64 look like garbled characters?

If the original encoded content was binary (an image, PDF, executable, or other non-text data), the decoded output cannot be displayed as readable text — you're seeing UTF-8 attempting to interpret raw bytes. This usually means the source isn't text to begin with, not that decoding failed. To recover the actual binary file, you'd need a binary-aware tool.

Q: Why is my JWT failing to decode?

Two common reasons: (1) you pasted only part of the JWT — make sure you're decoding ONE segment at a time (split the token on the dots), not the whole thing. (2) JWTs use URL-safe Base64 — switch the mode toggle to URL-safe and try again. For full JWT inspection with signature verification, use our dedicated JWT Decoder.

Q: Is Base64 a form of encryption or compression?

Neither. Base64 is an encoding — a deterministic, reversible mapping that lets binary data travel safely through text-only channels (JSON, XML, HTTP headers, email). It does not protect content from being read (encoding ≠ encryption) and it actually makes data larger, not smaller (encoding ≠ compression).

Q: Why is the Base64 output longer than the input?

Base64 uses 6 bits per character to represent 8-bit binary, so every 3 input bytes produce 4 output characters — about a 33% increase. There's no way to avoid this overhead with Base64; if size matters and the channel allows binary, send the raw bytes instead.

Q: What's a Base64 data URI?

A data URI embeds content directly in a URL using the syntax data:[mime-type];base64, . Example: data:image/png;base64,iVBORw0KGgo... You can use this in CSS (background-image), HTML (img src), or anywhere a URL is expected. Best for tiny assets — larger ones bloat HTML/CSS files and hurt cache efficiency.

Q: Can I decode a Base64 string that was copied with extra newlines?

Yes. The tool ignores whitespace inside the input — line breaks, spaces, and tabs are stripped before decoding. PEM-style content (which wraps at 64-76 chars per line) and shell-copied output paste cleanly.

Q: Why does the "likely Base64" indicator say No on valid text?

The detector checks both the character set (only Base64 alphabet allowed, plus padding) and the length (a multiple of 4 for standard Base64). Plain English text usually contains characters outside the Base64 alphabet (spaces, punctuation, etc.) and so is correctly flagged as not-Base64. This is a feature — it prevents the decoder from trying to interpret arbitrary text as Base64 and producing nonsense.

Convierte texto plano a Base64 y viceversa.

Tus datos se quedan en tu dispositivoSin subida, sin servidorFunciona sin conexión

Modo

Entrada

Salida codificada

aGVsbG8=

Salida decodificada

—

Bytes de entrada

Parece Base64

Estado

La entrada parece texto plano; decodificación omitida.

Por qué usar esta herramienta

Codifica o decodifica valores Base64 directamente en el navegador para depuración y transformación rápida.

Útil al trabajar con APIs, tokens y recursos embebidos.

Los datos no salen de tu navegador.

Cómo usarla

01Introduce texto plano o una cadena Base64.

02Consulta los resultados codificados y decodificados en paralelo.

Revisiones rápidas antes de copiar

Confirma que el formato de entrada es el que esperabas.

Revisa el resultado antes de usarlo en un documento, URL, configuración o mensaje.

Copia solo el resultado que necesitas.

Preguntas frecuentes

¿Se envían mis datos a un servidor?

No. Toda la codificación y decodificación Base64 ocurre localmente en tu navegador.

¿Base64 es un tipo de cifrado?

No. Base64 es codificación, no cifrado. Cualquiera puede decodificarlo en segundos. Nunca lo uses para proteger información sensible.

¿Por qué el texto decodificado muestra caracteres extraños?

Si los datos originales eran binarios (imagen, PDF, ejecutable), la salida decodificada es binaria y no puede mostrarse como texto legible.

Herramientas relacionadas

Image to Data URL Generator

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Decodifica, firma y verifica tokens JWT de forma local.

Codificador / Decodificador de URL

Codifica y decodifica valores de texto seguros para URL.

ConversoresParte de Conversores →

Codificador / Decodificador Base64

Convierte texto plano a Base64 y viceversa.

Tus datos se quedan en tu dispositivoSin subida, sin servidorFunciona sin conexión

Modo

Entrada

Salida codificada

aGVsbG8=

Salida decodificada

—

Bytes de entrada

Parece Base64

Estado

La entrada parece texto plano; decodificación omitida.

Por qué usar esta herramienta

Codifica o decodifica valores Base64 directamente en el navegador para depuración y transformación rápida.

Útil al trabajar con APIs, tokens y recursos embebidos.

Los datos no salen de tu navegador.

Cómo usarla

01Introduce texto plano o una cadena Base64.

02Consulta los resultados codificados y decodificados en paralelo.

Revisiones rápidas antes de copiar

Confirma que el formato de entrada es el que esperabas.

Revisa el resultado antes de usarlo en un documento, URL, configuración o mensaje.

Copia solo el resultado que necesitas.

Preguntas frecuentes

¿Se envían mis datos a un servidor?

No. Toda la codificación y decodificación Base64 ocurre localmente en tu navegador.

¿Base64 es un tipo de cifrado?

No. Base64 es codificación, no cifrado. Cualquiera puede decodificarlo en segundos. Nunca lo uses para proteger información sensible.

¿Por qué el texto decodificado muestra caracteres extraños?

Si los datos originales eran binarios (imagen, PDF, ejecutable), la salida decodificada es binaria y no puede mostrarse como texto legible.

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Herramienta JWT→

Codificador / Decodificador de URL→

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Codificador / Decodificador de URL

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Codificador / Decodificador de URL