Free batch Base64 tool: paste a list of strings (one per line) and Base64-encode or decode every line at once. Invalid lines are flagged per line, not aborted. Runs in your browser.
—
Enter a list of strings above, then press Process All.
Processed lines
#
Input
Result
How base64 batch works
This tool encodes or decodes every line in a list at once, so you can convert a whole column of strings to or from Base64 in one pass instead of processing them one by one. Each line is handled independently, and every output maps to the input line at the same position.
Pick a mode (encode or decode), paste one string per line, and the tool runs the standard Base64 transform on each line. Encoding converts text to a Base64 string; decoding reverses it. The transformation matches the single Base64 Encoder & Decoder.
If a single line cannot be decoded (for example, it is not valid Base64), that line is marked with an error but the rest of the list still processes. Empty lines are preserved and stay empty, so your line numbering never shifts.
Frequently asked questions
How is this different from the Base64 Encoder & Decoder?
The Base64 Encoder & Decoder handles a single string. This batch version takes a list of separate strings (one per line) and encodes or decodes each one independently, so a whole column of values comes out in one click.
What happens when a line is not valid Base64?
In decode mode, any line that is not valid Base64 is marked with a per-line error and produces an empty result, while the rest of the list still decodes normally. This lets you clean up a mixed list without it aborting halfway.
Can Base64 encode any text?
Base64 can encode any binary data, but the browser btoa function only accepts Latin-1 characters (code points up to 255). To Base64-encode Unicode text, first encode it to UTF-8 bytes. This tool encodes each line with the standard browser Base64 routine.
What happens to empty lines?
Empty lines are kept in place and stay empty, so your line numbering is preserved and every input line maps to exactly one output line.
