Does Base64 Byte Length upload my file or text to Tool-You servers?

No. Base64 Byte Length runs in this browser tab. Files stay on the device. Limit note: Base64 text.

Should I use File to Base64 instead of Base64 Byte Length?

Use Base64 Byte Length when you need Decoded byte length of Base64. Use File to Base64 when you need Encode any file as a data URL. They share a category (Convert) but not the same job.

Base64 Byte Length

Decoded byte length of Base64.

Estimates byte length from Base64/Base64URL text. Unlike File to Base64 this measures. Bad alphabet fails.

What Base64 Byte Length does

Estimates byte length from Base64/Base64URL text. Unlike File to Base64 this measures. Bad alphabet fails.

The interactive controls for Base64 Byte Length load after this article so crawlers still read the instructions. Path /convert/base64-byte-length is the canonical address. Work happens on this device; Tool-You does not take a copy of the file or pasted text for Base64 Byte Length.

How to use Base64 Byte Length

Keep this tab on Base64 Byte Length (/convert/base64-byte-length). Pasting into the wrong Convert tool (for example File to Base64) changes the job.
Paste or type the input Base64 Byte Length expects. Path hint: convert · base64 byte length. Decoded byte length of Base64.
Apply the Base64 Byte Length action only. Base64 Encode / Decode is a different transform (Encode or decode UTF-8 text as Base64 or Base64URL.). Estimates byte length from Base64/Base64URL text. Unlike File to Base64 this measures. Bad alphabet fails.
Copy the output of Base64 Byte Length if you need it elsewhere. Size/complexity still follows: Base64 text.
If the text job is actually Encode any file as a data URL., leave Base64 Byte Length and open File to Base64.

When not to use Base64 Byte Length

Skip Base64 Byte Length when a neighbor tool matches better — start with File to Base64 or Base64 Encode / Decode — or when the description already warns the job will fail. In the tool’s own words: Estimates byte length from Base64/Base64URL text. Unlike File to Base64 this measures. Bad alphabet fails.

Questions about Base64 Byte Length

What does Base64 Byte Length do that other Convert pages on this site do not?: Estimates byte length from Base64/Base64URL text. Unlike File to Base64 this measures. Bad alphabet fails. Short version: Decoded byte length of Base64.
Does Base64 Byte Length upload my file or text to Tool-You servers?: No. Base64 Byte Length runs in this browser tab. Files stay on the device. Limit note: Base64 text.
Should I use File to Base64 instead of Base64 Byte Length?: Use Base64 Byte Length when you need Decoded byte length of Base64. Use File to Base64 when you need Encode any file as a data URL. They share a category (Convert) but not the same job.
What are the limits of Base64 Byte Length?: Base64 text. Also: Estimates byte length from Base64/Base64URL text. Unlike File to Base64 this measures. Bad alphabet fails.