What Is Base64 Encode & Decode?
Base64 is a binary-to-text encoding defined in RFC 4648. It packs every three bytes into four ASCII characters using 6-bit groups, with = padding when needed. A Base64 decode tool reverses that mapping; encode builds it. MIME email, JSON APIs, and data URIs rely on it heavily.
Encoding is not encryption. Anyone can decode the string. Expect about 33% size overhead versus the original bytes.
base64url and Data URIs
The base64url variant swaps +// for -/_ and often drops padding so values survive in URLs. Data URIs embed Base64 after data:<mime>;base64,—useful for image Base64 decode previews and small assets.
data:image/png;base64,iVBORw0KGgoAAAANSUhEUg...Files, Images, and PDFs
Upload a file to encode it, or paste Base64 (including a data URI) to decode and download. Image and PDF signatures are sniffed when possible so Base64 decode to PDF / image workflows restore the right extension.
Python, Linux, macOS, PowerShell, and Node
Developers often use Python base64.b64decode, Linux/macOS base64 -d, bash pipelines, PowerShell FromBase64String, Windows certutil -decode, browser btoa/atob, and Node Buffer.from. This online Base64 decode tool is for quick UTF-8–safe checks without opening a terminal.
Base64 Encode & Decode FAQs
- What is a Base64 decode / encode tool?
- Base64 is a binary-to-text encoding from RFC 4648. A Base64 decode tool turns encoded text back into bytes or UTF-8 strings; encode does the reverse. This Base64 decode encode page also handles files, images, base64url, and data URIs in your browser.
- Is Base64 encryption?
- No. Encoding is not encryption. Anyone can Base64 decode a string. It only makes binary safe for text channels (email MIME, JSON, URLs) and adds about 33% size overhead.
- What is base64url?
- The base64url variant replaces + and / with - and _ and often omits = padding so values are safer in URLs and filenames. Use Base64 decode URL mode when your token uses that alphabet.
- Can I Base64 decode a file, image, or PDF?
- Yes. Paste a Base64 decode string, data URI, or upload a file. Image Base64 decode and Base64 decode to PDF workflows run locally—download the restored file without uploading it to a server.
- How do Python, Linux, macOS, and PowerShell decode Base64?
- Common commands include Python base64.b64decode, Linux/macOS base64 -d, bash Base64 decode pipelines, PowerShell FromBase64String, and Windows certutil -decode. This online Base64 decode tool is for quick checks without the command line.
- How do browsers encode UTF-8 text?
- Browser btoa()/atob() work on binary strings. This tool UTF-8–encodes text first (similar to TextEncoder / Buffer.from) so non-ASCII characters encode and decode correctly.
