Base64 Normalizer

Clean up and standardize your Base64 strings. Remove whitespace, fix padding, convert between standard and URL-safe formats, and format with MIME-style line breaks.

Last Updated: August 2026

Strip Whitespace

Remove all spaces, tabs, and newlines from your Base64 strings in one click.

Fix Padding

Automatically add or remove padding (= signs) to create valid, correctly padded Base64 strings.

URL-Safe Conversion

Convert between standard Base64 and URL-safe Base64 (for JWT, URLs, and API parameters).

MIME Formatting

Format Base64 with 76-character line breaks for email and MIME compatibility.

100% Client-Side — Your data never leaves your device

Paste a Base64 string above and click Normalize

Why this tool is safe

Your data never leaves your device — everything runs in your browser.

No server uploads. Other tools send your files to their servers. Ours don't.
Zero tracking of content. We never see, store, or log anything you convert.
Works offline. Once loaded, the tool works without an internet connection.

Fix Padding

Automatically adds or removes Base64 padding (= signs) to create valid strings.

Convert Formats

Switch between standard Base64 and URL-safe Base64 (for JWT, URLs, and APIs).

MIME Formatting

Format Base64 with 76-character line breaks for email and MIME compatibility.

Frequently Asked Questions

Search below or browse through our most commonly asked questions.

The normalizer takes a poorly formatted Base64 string (with spaces, newlines, tabs, or missing padding) and cleans it into a single, continuous, properly-padded standard Base64 string.
Use it when copying Base64 from emails, PDFs, or formatted JSON logs where line breaks or spaces might have corrupted the string.