SEERSeerKits

Base64 Encode and Decode Online

Convert files or text to Base64 and back for APIs, data URIs, and debugging. Purely local FileReader processing — free with no upload.

Local Processing

Drag and drop your file here

or click to browse from your device

*txt

Maximum file size: 100 MB

Import fromOneDrive URLs supported

Supported Formats

File types you can use with Base64 Encoder.

Supported Input Formats

*txt

Available Output Formats

txt*

Usage Limits

Free tier limits for Base64 Encoder on the web.

  • Max file size

    100 MB per file

  • Daily free uses

    30 conversions per day

  • Batch limit

    Up to 1 file at once

Need more? Try the Seer app for expanded limits.

Privacy & Processing

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使用方法

How to encode or decode Base64 with SeerKits

  1. 1

    Choose encode or decode

    Select whether to convert a file to Base64 text or restore Base64 back to a file.

  2. 2

    Provide input

    Upload the source file or paste Base64 text depending on the mode.

  3. 3

    Copy or download result

    Copy the Base64 string or download the decoded binary output.

Need more power?

Take Base64 Encoder further with Seer File

The web tool is perfect for quick jobs. When you need bigger files, batch workflows, or pro-grade controls, continue in the Seer app ecosystem — same privacy-first approach, more headroom.

  • Larger file limits beyond the web free tier
  • Batch processing for multiple files at once
  • Advanced codec and quality options
  • Offline processing when you need it on the go
Download Seer File

よくある質問

When should I use Base64 encoding?
Base64 embeds binary data in text — common for JSON APIs, email attachments, and data URIs in HTML or CSS.
Does encoding increase file size?
Yes — Base64 expands data by roughly 33%. Use it when text transport is required, not for general compression.
Is my file uploaded during encoding?
Never — SeerKits reads files through the browser File API and encodes entirely on your device.