Why does my Base64 string end in one or two equals signs?

Padding. Base64 works in blocks of three bytes, and the equals signs mark how many bytes the last block was short. It is normal and expected.

Can I decode a data URI with this?

Yes, but strip the prefix first. Everything after the comma in data:image/png;base64, is the Base64 payload.

Base64 Encoder / Decoder

Convert text to Base64 and back. Unicode is handled correctly, so emoji and accented characters survive the round trip.

Plain text

Base64

About this tool

Encodes text to Base64 and decodes it back. Base64 exists to move arbitrary bytes through channels that only reliably carry text, which is why it turns up in data URIs, email attachments, JSON payloads and HTTP basic auth.

How to use it

1Paste your text or your Base64 string.
2Pick the direction, encode or decode.
3Copy the result.

Good to know

Unicode is handled properly

Text is encoded as UTF-8 before Base64 is applied, so accented letters, Cyrillic, Greek and emoji all survive the round trip. The naive approach using btoa alone throws on anything above Latin-1.

It is encoding, not encryption

Base64 is trivially reversible and offers no secrecy whatsoever. Anyone holding the string can read it. Never use it to hide a password or a key.