Base64 Encoder Decoder Online — No Login Required
Text · Image · File — URL-safe mode · auto-detect · live image preview — 100% browser-side
Paste text → get Base64
Real-time · No button click · 200ms debounce
The fastest Base64 tool online — no login, no ads, no data upload. Encode and decode Base64 in real-time directly in your browser. Supports text, images (JPG, PNG, GIF, WebP), and any file type up to 5 MB. Shareable URL, URL-safe mode, usage history.
What is Base64 Encoding?
Base64 encoding converts binary data into a string of 64 safe ASCII characters — A–Z, a–z, 0–9, +, and /. It is the standard way to embed binary content (images, files, certificates) inside JSON, XML, HTML, and email without breaking the format. The encoded output is ~33% larger than the original.
Standard vs URL-Safe Base64
Standard Base64 uses + and / which have special meaning in URLs. URL-safe Base64 (Base64URL) replaces +→- and /→_ and removes = padding. Use URL-safe mode for JWT tokens, OAuth tokens, and URL query parameters.
Frequently Asked Questions
Is this Base64 tool really free with no limits?
Yes — completely free, no signup, no rate limits. The tool runs 100% in your browser using the native btoa() / atob() Web APIs. There is no server involved, so there are no API calls to limit or pay for.
Does this tool work offline?
Yes — once the page is loaded, all encoding and decoding happens locally in your browser. No internet connection is needed for the actual conversion. You only need internet to load the page initially.
Is my data private when using this online Base64 tool?
Completely private. Your text, images, and files are processed entirely in your browser and never sent to any server. Not even CalcNation's server sees your data. You can verify this by opening DevTools → Network tab while encoding.
Which browsers support this Base64 tool?
All modern browsers — Chrome, Firefox, Safari, Edge (2020+). The tool uses the standard btoa(), atob(), and FileReader APIs which are available in all major browsers. No extensions or plugins required.
Can I use this for API testing and JWT debugging?
Yes — this is a common use case. Enable URL-safe mode for JWT token Base64URL payload decoding. Switch to Decode, paste the payload section of your JWT (between the first and second dots), and read the decoded claims.