Free Base64 Encoder & Decoder — Text, Images & Files
Encode and decode Base64 strings, text, and image files instantly in your browser. Supports URL-safe Base64. Free, offline, 100% private.
This tool is part of PDFLocal's full productivity suite. Access it on the main dashboard:
Open Free Base64 Encoder & Decoder ToolFree Base64 Encoder & Decoder — Text, Images & Files
Encode and decode Base64 strings, text, and image files instantly in your browser. Supports URL-safe Base64. Free, offline, 100% private. This tool runs 100% in your browser — your data is never sent to any server, logged, or stored anywhere outside your own device. This makes PDFLocal the most private choice for handling sensitive text, images, or file data.
Frequently Asked Questions
What is Base64 encoding and why is it used?
Base64 is a binary-to-text encoding scheme that converts binary data (images, files, arbitrary bytes) into a string of printable ASCII characters. It is used whenever binary data needs to be transmitted or stored in systems that only handle text. Common use cases include: embedding images directly in HTML or CSS using data URLs (eliminating a separate HTTP request), encoding file attachments in email (MIME format uses Base64), transmitting binary data in JSON API payloads (which are text-based), storing binary data in text-based configuration files, and encoding authentication credentials in HTTP Basic Auth headers. Base64 is an encoding (reversible transformation), not encryption — it does not protect data, it only converts its representation.
Does Base64 encoding make data secure?
No. Base64 encoding is not a security measure and provides no confidentiality protection whatsoever. Anyone who receives a Base64-encoded string can trivially decode it using any Base64 decoder (including our tool). Do not use Base64 to "hide" sensitive information. If you need to protect data, use proper encryption (AES, RSA, or other cryptographic algorithms). Base64 is sometimes confused with encryption because encoded data looks like random characters, but this is purely cosmetic — the data is completely reversible by anyone. Base64 is useful for data representation and transmission compatibility, not security.
What is URL-safe Base64?
Standard Base64 uses the characters A-Z, a-z, 0-9, +, and / for encoding, plus = for padding. The + and / characters have special meaning in URLs (+ means space, / is a path separator), which causes problems when Base64 strings appear in URL parameters or paths. URL-safe Base64 (also called Base64url) substitutes + with - (hyphen) and / with _ (underscore), making the encoded string safe to include in URLs without percent-encoding. The padding character = is often omitted as well in URL contexts. PDFLocal's Base64 tool supports both standard and URL-safe Base64 encoding and decoding.
How large can files be for Base64 encoding?
Base64 encoding increases data size by approximately 33% (every 3 bytes become 4 Base64 characters). For text encoding/decoding, PDFLocal handles strings of any reasonable length in milliseconds. For image encoding (converting an image file to a Base64 data URL), the practical browser limit is usually around 50-100MB of source image data — above this, some browsers may struggle with the resulting string size. For very large files, Base64 is generally not the right tool — direct file transfer (using proper multipart/form-data HTTP uploads) is more efficient for large binary files than Base64 encoding.