Base64 Repair Tool

Got a broken Base64 string? Paste it in and let the tool automatically fix common issues like invalid characters, missing padding, whitespace, and more.

Last Updated: August 2026

Remove Invalid Characters

Strip out characters that don't belong in Base64 — spaces, symbols, and other junk.

Fix Padding Issues

Correct missing or excessive padding (= signs) to create valid, decodable Base64 strings.

URL-Safe → Standard

Automatically convert URL-safe characters (-, _) back to standard Base64 (+, /).

Strip Data URI Prefix

Remove data:image/png;base64, style prefixes to get clean Base64 strings ready for decoding.

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

Paste a malformed Base64 string above to repair it

Invalid Characters

Removes characters that don't belong in Base64, like spaces, newlines, or special symbols.

Padding Fixes

Corrects missing or excessive padding (= signs) to create valid Base64 strings.

URL-safe Conversion

Automatically converts URL-safe characters (-, _) back to standard Base64 (+, /).

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.

Frequently Asked Questions

Search below or browse through our most commonly asked questions.

It automatically calculates and appends missing '=' padding, strips completely invalid characters, and attempts to recover the closest valid Base64 string.
If the string only lacked padding, no data is lost. If illegal characters were stripped, the resulting binary might differ from the original intended data.